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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 855abed3cbf1a6c732fab5ae85bad7bbadc35789 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 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 Lattnerfa730212004-12-09 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 Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 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 Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 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 Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]46 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]47 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]48 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]49 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]50 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]51 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]52 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]53 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]54 </ol>
55 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]56 <li><a href="#typesystem">Type System</a>
57 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]58 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]59 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]60 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]61 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 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 Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]65 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]66 </ol>
67 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]68 <li><a href="#t_derived">Derived Types</a>
69 <ol>
Chris Lattnerfdfeb692010-02-12 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 Brukman9d0919f2003-11-08 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 Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]81 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]82 </ol>
83 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]84 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]87 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]88 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]89 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]90 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 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 Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]93 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]94 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]95 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]96 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]97 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]98 <li><a href="#othervalues">Other Values</a>
99 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]100 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]101 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]102 </ol>
103 </li>
Chris Lattner857755c2009-07-20 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 Lattner401e10c2009-07-20 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 Lattner857755c2009-07-20 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 Lattner00950542001-06-06 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 Lattner261efe92003-11-25 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]121 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]122 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]125 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 </ol>
127 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]128 <li><a href="#binaryops">Binary Operations</a>
129 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]130 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]131 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 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 Spencer0a783f72006-11-02 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 </ol>
143 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]144 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
145 <ol>
Reid Spencer8e11bf82007-02-02 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]149 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]150 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]152 </ol>
153 </li>
Chris Lattner3df241e2006-04-08 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]159 </ol>
160 </li>
Dan Gohmana334d5f2008-05-12 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 Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]167 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]168 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]169 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]173 </ol>
174 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]175 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 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 Spencerd4448792006-11-09 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 Spencer72679252006-11-11 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 Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]188 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]189 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]190 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]191 <li><a href="#otherops">Other Operations</a>
192 <ol>
Reid Spencerf3a70a62006-11-18 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]195 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]196 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]198 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]199 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]200 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]203 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]204 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]205 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
206 <ol>
Reid Spencera3e435f2007-04-04 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]210 </ol>
211 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]212 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
213 <ol>
Reid Spencera3e435f2007-04-04 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]219 <li><a href="#int_codegen">Code Generator Intrinsics</a>
220 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]221 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
222 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
224 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
225 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
226 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
227 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]228 </ol>
229 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]230 <li><a href="#int_libc">Standard C Library Intrinsics</a>
231 <ol>
Reid Spencera3e435f2007-04-04 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 Gohman91c284c2007-10-15 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 Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]240 </ol>
241 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]242 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]243 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]244 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 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 Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]248 </ol>
249 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]250 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
251 <ol>
Bill Wendlingda01af72009-02-08 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 Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]257 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]258 </ol>
259 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]260 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
261 <ol>
Chris Lattner82c3dc62010-03-14 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 Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]264 </ol>
265 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]266 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]267 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]268 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]269 <ol>
270 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]271 </ol>
272 </li>
Bill Wendling3c44f5b2008-11-18 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 Lewyckycc271862009-10-13 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 Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]298 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]299 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]301 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]302 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]304 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 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 Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]308 <li><a href="#int_objectsize">
309 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]310 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]311 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]312 </ol>
313 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]314</ol>
Chris Lattnerd7923912004-05-23 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]319</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]320
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]321<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]322<div class="doc_section"> <a name="abstract">Abstract </a></div>
323<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]324
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]325<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]333</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]334
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]335<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]336<div class="doc_section"> <a name="introduction">Introduction</a> </div>
337<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]339<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]340
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]349
Bill Wendlinge910b4c2009-07-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]357 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]358 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]359
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]360</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]362<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]363<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]364
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]365<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]366
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]371
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]372<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]373<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]375</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]376</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]377
Bill Wendlingf82d40a2009-11-02 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]439<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]441%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]443</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]445<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]447<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]449%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]451</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]452
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]453<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]454
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]455<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456<pre>
Gabor Greifec58f752009-10-28 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 Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]459%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]461</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]465
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]466<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]468 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]469
470 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]471 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]473 <li>Unnamed temporaries are numbered sequentially</li>
474</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]475
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]476<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]480
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]481</div>
Chris Lattnerfa730212004-12-09 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 Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]499
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]500<div class="doc_code">
Bill Wendlingf82d40a2009-11-02 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]504
505<i>; External declaration of the puts function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]506<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]507
508<i>; Definition of main function</i>
Bill Wendlingf82d40a2009-11-02 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]512
Bill Wendlingf82d40a2009-11-02 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 Patelcd1fd252010-01-11 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 Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]520</pre>
521</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]522
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]523<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]524 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]525 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]526 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
527 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]528
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]534
Chris Lattnere5d947b2004-12-09 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]544<p>All Global Variables and Functions have one of the following types of
545 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]546
547<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]555
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]557 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere1eaf912009-08-24 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 Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]563
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]568
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]570 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 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 Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]577
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]578 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]579 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]591
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]592 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 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 Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]604 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]605 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]606 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
607 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]608
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]609
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]611 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]616
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]617 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]621
Bill Wendlingf82d40a2009-11-02 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 Wendlinge910b4c2009-07-20 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 Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]631
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]632 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]633 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 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 Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]636</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]637
Bill Wendlinge910b4c2009-07-20 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 Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]641
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]642<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]643 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]644 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 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 Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]649
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]650 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]651 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]656</dl>
657
Bill Wendlinge910b4c2009-07-20 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 Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]668<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]669 or <tt>weak_odr</tt> linkages.</p>
670
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]671</div>
672
673<!-- ======================================================================= -->
674<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 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 Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]686
687<dl>
688 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]689 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694
695 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]696 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 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 Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]700 (Application Binary Interface).
701 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]705
706 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713
Chris Lattner29689432010-03-11 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 Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]734 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]735 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]736 target-specific calling conventions to be used. Target specific calling
737 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]738</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]739
740<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]741 support Pascal conventions or any other well-known target-independent
742 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]743
744</div>
745
746<!-- ======================================================================= -->
747<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]748 <a name="visibility">Visibility Styles</a>
749</div>
750
751<div class="doc_text">
752
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]753<p>All Global Variables and Functions have one of the following visibility
754 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]755
756<dl>
757 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]758 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]763
764 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]765 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]770
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]771 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]772 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776</dl>
777
778</div>
779
780<!-- ======================================================================= -->
781<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 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 Wendlinge910b4c2009-07-20 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 Lattnere7886e42009-01-11 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 Wendlinge910b4c2009-07-20 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 Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800
801<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 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 Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]810
811</div>
812
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]813<!-- ======================================================================= -->
814<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]815 <a name="globalvars">Global Variables</a>
816</div>
817
818<div class="doc_text">
819
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]820<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 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 Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]831
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]838
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]844
Bill Wendlinge910b4c2009-07-20 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 Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]850
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]851<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]852 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]853
Chris Lattnerce99fa92010-04-28 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 Lattner2d4b8ee2010-04-28 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 Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]863
Bill Wendlinge910b4c2009-07-20 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 Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]866
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]867<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]868<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]869@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]870</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]871</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]872
Chris Lattnerfa730212004-12-09 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 Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]883<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]893
Bill Wendlinge910b4c2009-07-20 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]896 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]901
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]902<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]907
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]908<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]913
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]914<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]915 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]916
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]917<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 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 Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]922
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]923<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]924<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]925<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]926define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 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 Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]932</div>
933
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]949<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]950<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]951@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]952</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]953</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]954
955</div>
956
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]957<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 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 Lattnere6a5ddd2010-01-15 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 Patelcd1fd252010-01-11 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 Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlinge910b4c2009-07-20 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 Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]993
994<div class="doc_code">
995<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]996declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]997declare i32 @atoi(i8 zeroext)
998declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]999</pre>
1000</div>
1001
Bill Wendlinge910b4c2009-07-20 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 Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1007<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1008 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1012
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1017
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1024
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1025 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1040 <dt><tt><b>sret</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1048 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1058 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1063 <dt><tt><b>nest</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1068
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1069</div>
1070
1071<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1072<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1073 <a name="gc">Garbage Collector Names</a>
1074</div>
1075
1076<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1077
Bill Wendlinge910b4c2009-07-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1083define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1084</pre>
1085</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1086
1087<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 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 Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1091</div>
1092
1093<!-- ======================================================================= -->
1094<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1095 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1096</div>
1097
1098<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1099
Bill Wendlinge910b4c2009-07-20 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 Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1104
Bill Wendlinge910b4c2009-07-20 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 Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1107
1108<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1109<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1110define void @f() noinline { ... }
1111define void @f() alwaysinline { ... }
1112define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1113define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1114</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1115</div>
1116
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1117<dl>
Charles Davis1e063d12010-02-12 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1123 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1127
Jakob Stoklund Olesen570a4a52010-02-06 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1133 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1137
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1138 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1142
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1147
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1148 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1152
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1153 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1163
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1164 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1174
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1175 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1186 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlingc39e3e02009-07-20 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1195
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This attributes disables implicit floating point instructions.</dd>
1202
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b>naked</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1206</dl>
1207
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1208</div>
1209
1210<!-- ======================================================================= -->
1211<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1212 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1213</div>
1214
1215<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 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 Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1221
Bill Wendling2f7a8b02007-05-29 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 Lattner4e9aba72006-01-23 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1231 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1232
Bill Wendlinge910b4c2009-07-20 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 Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1236</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1237
Reid Spencerde151942007-02-19 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1244
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1245<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1263 bits with the most significance have the lowest address location.</dd>
1264
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1265 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1266 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1267 the bits with the least significance have the lowest address
1268 location.</dd>
1269
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1270 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1271 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 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 Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1280 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1281 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282 <i>size</i>.</dd>
1283
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1284 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1285 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1291 <i>size</i>.</dd>
1292
Daniel Dunbar87bde0b2009-06-08 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1295 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1301 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1302 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1303</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1304
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1305<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1306 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1310<ul>
1311 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1312 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencerde151942007-02-19 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 Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1317 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencerde151942007-02-19 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 Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1324 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1325</ul>
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1332 specification is used.</li>
1333
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1334 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1342 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1346</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1347
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1348</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1349
Dan Gohman556ca272009-07-27 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 Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1357<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1358with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 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 Bolka55e459a2009-07-29 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 Gohman556ca272009-07-27 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 Bolka55e459a2009-07-29 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 Gohman556ca272009-07-27 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 Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1383 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 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 Bolka55e459a2009-07-29 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 Gohman556ca272009-07-27 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 Yasskin93e066d2010-04-26 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1420<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1421<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1422<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1423
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1424<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1425
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1426<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1433
1434</div>
1435
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1436<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1437<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1438Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1439
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1440<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1441
1442<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1443
1444<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1445 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1446 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1447 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1448 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1449 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1450 </tr>
1451 <tr>
Chris Lattner4f69f462008-01-04 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1454 </tr>
1455 <tr>
1456 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 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 Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1460 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1461 <a href="#t_struct">structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1462 <a href="#t_union">union</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1463 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1464 <a href="#t_label">label</a>,
1465 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1466 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1467 </tr>
Chris Lattner4f69f462008-01-04 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 Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1472 <a href="#t_floating">floating point</a>,
1473 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1474 </tr>
1475 <tr>
1476 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1477 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 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 Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1482 <a href="#t_union">union</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1483 <a href="#t_vector">vector</a>,
1484 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1485 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1486 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1487 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1488</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1489
Bill Wendlinge910b4c2009-07-20 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 Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1492 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1493
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1494</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1495
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1496<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1497<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1498
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1499<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1500
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1501<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1502 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1503
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1504</div>
1505
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1506<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 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 Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1540</div>
1541
1542<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 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 Wendlinge910b4c2009-07-20 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 Lattner4f69f462008-01-04 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 Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1564
Chris Lattner4f69f462008-01-04 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 Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1569<pre>
1570 void
1571</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1572
Chris Lattner4f69f462008-01-04 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 Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1579
Chris Lattner4f69f462008-01-04 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 Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1584<pre>
1585 label
1586</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1587
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1588</div>
1589
Nick Lewycky7a0370f2009-05-30 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 Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1594
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1595<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 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 Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1599
1600<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1601<pre>
1602 metadata
1603</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1604
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1605</div>
1606
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1607
1608<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1609<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1610
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1611<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1612
Bill Wendlinge910b4c2009-07-20 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 Lewyckyec38da42009-09-27 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 Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1619
Chris Lattnerfdfeb692010-02-12 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 Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1635</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1636
1637<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1638<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1639
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1640<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1641
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1642<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1643<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1646
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1647<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1648<pre>
1649 [&lt;# elements&gt; x &lt;elementtype&gt;]
1650</pre>
1651
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1654
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1655<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1656<table class="layout">
1657 <tr class="layout">
Chris Lattner23ff1f92007-12-19 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1668 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1669</table>
Reid Spencerd3f876c2004-11-01 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 Lattner23ff1f92007-12-19 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1683 </tr>
1684</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1685
Dan Gohman7657f6b2009-11-09 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 Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1692
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1693</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1694
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1695<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1696<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1697
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1698<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1699
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1700<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnerfdfeb692010-02-12 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 Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1706
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1707<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1708<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1709 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1710</pre>
1711
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1712<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlinge910b4c2009-07-20 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 Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1717 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1718 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1719
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1720<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1721<table class="layout">
1722 <tr class="layout">
Reid Spencer92f82302006-12-31 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1725 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1726 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1727 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1728 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1729 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 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 Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1732 </td>
1733 </tr><tr class="layout">
1734 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 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 Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1738 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1739 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1740 </tr><tr class="layout">
1741 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 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 Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1744 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1745 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1746</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1747
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1748</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1751<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1752
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1754
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1755<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Yasskin7a088cf2010-01-11 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1767<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1768<pre>
1769 { &lt;type list&gt; }
1770</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1771
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1772<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1773<table class="layout">
1774 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1783 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1784</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1785
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1786</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1787
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1788<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1789<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1790</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1791
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1792<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1793
Andrew Lenharth75e10682006-12-08 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 Wendlinge910b4c2009-07-20 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 Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1804<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1805<pre>
1806 &lt; { &lt;type list&gt; } &gt;
1807</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1808
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1809<h5>Examples:</h5>
1810<table class="layout">
1811 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 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 Wendlinge36dccc2008-09-07 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 Cohen6f1cc772007-04-22 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 Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1821 </tr>
1822</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1823
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1824</div>
1825
1826<!-- _______________________________________________________________________ -->
Chris Lattnerfdfeb692010-02-12 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 Gohman2eddfef2010-02-25 16:51:31 +0000[diff] [blame]1844<p>Union members are accessed using '<tt><a href="#i_load">load</a></tt> and
Chris Lattnerfdfeb692010-02-12 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1874<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1875
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1876<div class="doc_text">
1877
1878<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 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 Wendlinge910b4c2009-07-20 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 Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1889
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1890<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1891<pre>
1892 &lt;type&gt; *
1893</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1894
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1895<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1896<table class="layout">
1897 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1898 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 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 Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1905 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1912 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1913</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1914
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1915</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1916
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1917<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1918<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1919
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1920<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1921
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1922<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1926 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1927 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1928
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1929<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1930<pre>
1931 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1932</pre>
1933
Bill Wendlinge910b4c2009-07-20 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 Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1936
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1937<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1938<table class="layout">
1939 <tr class="layout">
Chris Lattner23ff1f92007-12-19 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1950 </tr>
1951</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1952
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1953</div>
1954
Chris Lattner69c11bb2005-04-25 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 Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1960<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 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 Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1964
1965<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1966<pre>
1967 opaque
1968</pre>
1969
1970<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1971<table class="layout">
1972 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1973 <td class="left"><tt>opaque</tt></td>
1974 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1975 </tr>
1976</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1977
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1978</div>
1979
Chris Lattner242d61d2009-02-02 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1986
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1987<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1993
1994<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1995 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1996 { \2 }* %y = type { %y }*
1997 \1* %z = type %z*
1998</pre>
1999
Bill Wendlinge910b4c2009-07-20 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 Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2005
2006<h5>Syntax:</h5>
2007<pre>
2008 \&lt;level&gt;
2009</pre>
2010
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2011<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2012
2013<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 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 Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2025
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2026</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2027
Chris Lattnerc3f59762004-12-09 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2035 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2036
2037</div>
2038
2039<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2040<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2041
2042<div class="doc_text">
2043
2044<dl>
2045 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2046 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2047 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2048
2049 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2053
2054 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2055 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2061
2062 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2063 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2064 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2065</dl>
2066
Bill Wendlinge910b4c2009-07-20 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 Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2078<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2091</div>
2092
2093<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2094<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2095<a name="aggregateconstants"></a> <!-- old anchor -->
2096<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2097</div>
2098
2099<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2100
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2101<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2102 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2103
2104<dl>
2105 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2106 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2113
Chris Lattnerfdfeb692010-02-12 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2122 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2123 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2129
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2130 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2131 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2137
2138 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2139 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 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 Wendlinge910b4c2009-07-20 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 Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2145
2146 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2147 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 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 Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2169
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2170<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2171<pre>
Chris Lattnera18a4242007-06-06 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2175</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2176</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2177
2178</div>
2179
2180<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2181<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2182<div class="doc_text">
2183
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2184<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2185 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2188
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2189<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2193
Chris Lattner48a109c2009-09-07 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 Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2226such, it is unsafe to optimize or assume that the result of the and is undef.
Eric Christopher6c7e8a02009-12-05 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 Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2230-1.</p>
Chris Lattner48a109c2009-09-07 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2259
Chris Lattner48a109c2009-09-07 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 Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2284so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2285to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2286would not hold.</p>
Chris Lattner6e9057b2009-09-07 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 Lattner8e371aa2009-09-08 19:45:34 +0000[diff] [blame]2305has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2310
Chris Lattner6e9057b2009-09-07 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2322can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2327</div>
2328
2329<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 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 Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2333<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 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 Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2337 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2338
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2339<p>There is currently no way of representing a trap value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame^]2340 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2341 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2342
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2343<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2344
Dan Gohman34b3d992010-04-28 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
2360<li>Non-volatile loads and stores depend on the most recent stores to all of the
2361 referenced memory addresses, following the order in the IR
2362 (including loads and stores implied by intrinsics such as
2363 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2364
2365<!-- FIXME: padding in the middle of a struct -->
2366
2367<!-- TODO: In the case of multiple threads, this only applies to loads and
2368 stores from the same thread as the store, or which are sequenced after the
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2369 store by synchronization. -->
2370
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2371<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2372
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2373<li>An instruction with externally visible side effects depends on the most
2374 recent preceding instruction with externally visible side effects, following
2375 the order in the IR. (This includes volatile loads and stores.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2376
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2377<li>An instruction <i>control-depends</i> on a <a href="#i_br"><tt>br</tt></a>,
2378 <a href="#i_switch"><tt>switch</tt></a>, or
2379 <a href="#i_indirectbr"><tt>indirectbr</tt></a> if the <tt>br</tt>,
2380 <tt>switch</tt>, or <tt>indirectbr</tt> has multiple successors and the
2381 instruction is always executed when control transfers to one of the
2382 successors, and may not be executed when control is transfered to
2383 another.</li>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2384
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2385<!-- FIXME: invoke, unwind, exceptions -->
2386
2387<li>Dependence is transitive.</li>
2388
2389</ul>
2390</p>
2391
2392<p>Whenever a trap value is generated, all values which depend on it evaluate
2393 to trap. If they have side effects, the evoke their side effects as if each
2394 operand with a trap value were undef. If they have externally-visible side
2395 effects, the behavior is undefined.</p>
2396
2397<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2398
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2399<div class="doc_code">
2400<pre>
2401entry:
2402 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2403 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2404 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2405 store i32 0, i32* %trap_yet_again ; undefined behavior
2406
2407 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2408 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2409
2410 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2411
2412 %narrowaddr = bitcast i32* @g to i16*
2413 %wideaddr = bitcast i32* @g to i64*
2414 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2415 %trap4 = load i64* %widaddr ; Returns a trap value.
2416
2417 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2418 %br i1 %cmp, %true, %end ; Branch to either destination.
2419
2420true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2421 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2422 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2423 br label %end
2424
2425end:
2426 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2427 ; Both edges into this PHI are
2428 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2429 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2430
2431 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2432 ; so this is defined (ignoring earlier
2433 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2434</pre>
2435</div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2436
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2437</div>
2438
2439<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2440<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2441 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2442<div class="doc_text">
2443
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2444<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2445
2446<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2447 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2448 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2449
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2450<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2451 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2452 against null. Pointer equality tests between labels addresses is undefined
2453 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2454 equal to the null pointer. This may also be passed around as an opaque
2455 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2456 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2457 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2458
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2459<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2460 using the value as the operand to an inline assembly, but that is target
2461 specific.
2462 </p>
2463
2464</div>
2465
2466
2467<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2468<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2469</div>
2470
2471<div class="doc_text">
2472
2473<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2474 to be used as constants. Constant expressions may be of
2475 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2476 operation that does not have side effects (e.g. load and call are not
2477 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2478
2479<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2480 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2481 <dd>Truncate a constant to another type. The bit size of CST must be larger
2482 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2483
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2484 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2485 <dd>Zero extend a constant to another type. The bit size of CST must be
2486 smaller or equal to the bit size of TYPE. Both types must be
2487 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2488
2489 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2490 <dd>Sign extend a constant to another type. The bit size of CST must be
2491 smaller or equal to the bit size of TYPE. Both types must be
2492 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2493
2494 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2495 <dd>Truncate a floating point constant to another floating point type. The
2496 size of CST must be larger than the size of TYPE. Both types must be
2497 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2498
2499 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2500 <dd>Floating point extend a constant to another type. The size of CST must be
2501 smaller or equal to the size of TYPE. Both types must be floating
2502 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2503
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2504 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2505 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2506 constant. TYPE must be a scalar or vector integer type. CST must be of
2507 scalar or vector floating point type. Both CST and TYPE must be scalars,
2508 or vectors of the same number of elements. If the value won't fit in the
2509 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2510
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2511 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2512 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2513 constant. TYPE must be a scalar or vector integer type. CST must be of
2514 scalar or vector floating point type. Both CST and TYPE must be scalars,
2515 or vectors of the same number of elements. If the value won't fit in the
2516 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2517
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2518 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2519 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2520 constant. TYPE must be a scalar or vector floating point type. CST must be
2521 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2522 vectors of the same number of elements. If the value won't fit in the
2523 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2524
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2525 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2526 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2527 constant. TYPE must be a scalar or vector floating point type. CST must be
2528 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2529 vectors of the same number of elements. If the value won't fit in the
2530 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2531
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2532 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2533 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2534 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2535 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2536 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2537
2538 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2539 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2540 type. CST must be of integer type. The CST value is zero extended,
2541 truncated, or unchanged to make it fit in a pointer size. This one is
2542 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2543
2544 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2545 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2546 are the same as those for the <a href="#i_bitcast">bitcast
2547 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2548
2549 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2550 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2551 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2552 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2553 instruction, the index list may have zero or more indexes, which are
2554 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2555
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2556 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2557 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2558
2559 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2560 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2561
2562 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2563 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2564
2565 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2566 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2567 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2568
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2569 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2570 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2571 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2572
2573 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2574 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2575 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2576
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2577 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2578 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2579 be any of the <a href="#binaryops">binary</a>
2580 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2581 on operands are the same as those for the corresponding instruction
2582 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2583</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2584
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2585</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2587<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2588<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2589<!-- *********************************************************************** -->
2590
2591<!-- ======================================================================= -->
2592<div class="doc_subsection">
2593<a name="inlineasm">Inline Assembler Expressions</a>
2594</div>
2595
2596<div class="doc_text">
2597
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2598<p>LLVM supports inline assembler expressions (as opposed
2599 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2600 a special value. This value represents the inline assembler as a string
2601 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2602 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2603 expression has side effects, and a flag indicating whether the function
2604 containing the asm needs to align its stack conservatively. An example
2605 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2606
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2607<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2608<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2609i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2610</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2611</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2612
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2613<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2614 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2615 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2616
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2617<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2618<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2619%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2620</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2621</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2622
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2623<p>Inline asms with side effects not visible in the constraint list must be
2624 marked as having side effects. This is done through the use of the
2625 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2626
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2627<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2628<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2629call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2630</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2631</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2632
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2633<p>In some cases inline asms will contain code that will not work unless the
2634 stack is aligned in some way, such as calls or SSE instructions on x86,
2635 yet will not contain code that does that alignment within the asm.
2636 The compiler should make conservative assumptions about what the asm might
2637 contain and should generate its usual stack alignment code in the prologue
2638 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2639
2640<div class="doc_code">
2641<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2642call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2643</pre>
2644</div>
2645
2646<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2647 first.</p>
2648
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2649<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2650 documented here. Constraints on what can be done (e.g. duplication, moving,
2651 etc need to be documented). This is probably best done by reference to
2652 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2653</div>
2654
2655<div class="doc_subsubsection">
2656<a name="inlineasm_md">Inline Asm Metadata</a>
2657</div>
2658
2659<div class="doc_text">
2660
2661<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2662 attached to it that contains a constant integer. If present, the code
2663 generator will use the integer as the location cookie value when report
2664 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2665 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2666 source code that produced it. For example:</p>
2667
2668<div class="doc_code">
2669<pre>
2670call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2671...
2672!42 = !{ i32 1234567 }
2673</pre>
2674</div>
2675
2676<p>It is up to the front-end to make sense of the magic numbers it places in the
2677 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2678
2679</div>
2680
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2681<!-- ======================================================================= -->
2682<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2683 Strings</a>
2684</div>
2685
2686<div class="doc_text">
2687
2688<p>LLVM IR allows metadata to be attached to instructions in the program that
2689 can convey extra information about the code to the optimizers and code
2690 generator. One example application of metadata is source-level debug
2691 information. There are two metadata primitives: strings and nodes. All
2692 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2693 preceding exclamation point ('<tt>!</tt>').</p>
2694
2695<p>A metadata string is a string surrounded by double quotes. It can contain
2696 any character by escaping non-printable characters with "\xx" where "xx" is
2697 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2698
2699<p>Metadata nodes are represented with notation similar to structure constants
2700 (a comma separated list of elements, surrounded by braces and preceded by an
2701 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2702 10}</tt>". Metadata nodes can have any values as their operand.</p>
2703
2704<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2705 metadata nodes, which can be looked up in the module symbol table. For
2706 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2707
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2708<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2709 function is using two metadata arguments.
2710
2711 <div class="doc_code">
2712 <pre>
2713 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2714 </pre>
2715 </div></p>
2716
2717<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2718 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2719
2720 <div class="doc_code">
2721 <pre>
2722 %indvar.next = add i64 %indvar, 1, !dbg !21
2723 </pre>
2724 </div></p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2725</div>
2726
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2727
2728<!-- *********************************************************************** -->
2729<div class="doc_section">
2730 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2731</div>
2732<!-- *********************************************************************** -->
2733
2734<p>LLVM has a number of "magic" global variables that contain data that affect
2735code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2736of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2737section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2738by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2739
2740<!-- ======================================================================= -->
2741<div class="doc_subsection">
2742<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2743</div>
2744
2745<div class="doc_text">
2746
2747<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2748href="#linkage_appending">appending linkage</a>. This array contains a list of
2749pointers to global variables and functions which may optionally have a pointer
2750cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2751
2752<pre>
2753 @X = global i8 4
2754 @Y = global i32 123
2755
2756 @llvm.used = appending global [2 x i8*] [
2757 i8* @X,
2758 i8* bitcast (i32* @Y to i8*)
2759 ], section "llvm.metadata"
2760</pre>
2761
2762<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2763compiler, assembler, and linker are required to treat the symbol as if there is
2764a reference to the global that it cannot see. For example, if a variable has
2765internal linkage and no references other than that from the <tt>@llvm.used</tt>
2766list, it cannot be deleted. This is commonly used to represent references from
2767inline asms and other things the compiler cannot "see", and corresponds to
2768"attribute((used))" in GNU C.</p>
2769
2770<p>On some targets, the code generator must emit a directive to the assembler or
2771object file to prevent the assembler and linker from molesting the symbol.</p>
2772
2773</div>
2774
2775<!-- ======================================================================= -->
2776<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2777<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2778</div>
2779
2780<div class="doc_text">
2781
2782<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2783<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2784touching the symbol. On targets that support it, this allows an intelligent
2785linker to optimize references to the symbol without being impeded as it would be
2786by <tt>@llvm.used</tt>.</p>
2787
2788<p>This is a rare construct that should only be used in rare circumstances, and
2789should not be exposed to source languages.</p>
2790
2791</div>
2792
2793<!-- ======================================================================= -->
2794<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2795<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2796</div>
2797
2798<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2799<pre>
2800%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2801@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2802</pre>
2803<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.
2804</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2805
2806</div>
2807
2808<!-- ======================================================================= -->
2809<div class="doc_subsection">
2810<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2811</div>
2812
2813<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2814<pre>
2815%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2816@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2817</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2818
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2819<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.
2820</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2821
2822</div>
2823
2824
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2825<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2826<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2827<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2828
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2829<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2830
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2831<p>The LLVM instruction set consists of several different classifications of
2832 instructions: <a href="#terminators">terminator
2833 instructions</a>, <a href="#binaryops">binary instructions</a>,
2834 <a href="#bitwiseops">bitwise binary instructions</a>,
2835 <a href="#memoryops">memory instructions</a>, and
2836 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2837
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2838</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2839
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2840<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2841<div class="doc_subsection"> <a name="terminators">Terminator
2842Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2843
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2844<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2845
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2846<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2847 in a program ends with a "Terminator" instruction, which indicates which
2848 block should be executed after the current block is finished. These
2849 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2850 control flow, not values (the one exception being the
2851 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2852
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2853<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2854 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2855 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2856 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2857 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2858 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2859 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2860 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2861
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2862</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2863
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2864<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2865<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2866Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2867
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2868<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2869
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2870<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2871<pre>
2872 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2873 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2874</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2876<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2877<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2878 a value) from a function back to the caller.</p>
2879
2880<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2881 value and then causes control flow, and one that just causes control flow to
2882 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2883
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2884<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2885<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2886 return value. The type of the return value must be a
2887 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2888
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2889<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2890 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2891 value or a return value with a type that does not match its type, or if it
2892 has a void return type and contains a '<tt>ret</tt>' instruction with a
2893 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2894
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2895<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2896<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2897 the calling function's context. If the caller is a
2898 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2899 instruction after the call. If the caller was an
2900 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2901 the beginning of the "normal" destination block. If the instruction returns
2902 a value, that value shall set the call or invoke instruction's return
2903 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2904
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2905<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2906<pre>
2907 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2908 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2909 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2910</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2911
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2912</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2913<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2914<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2915
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2916<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2917
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2918<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2919<pre>
2920 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2921</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2922
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2923<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2924<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2925 different basic block in the current function. There are two forms of this
2926 instruction, corresponding to a conditional branch and an unconditional
2927 branch.</p>
2928
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2929<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2930<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2931 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2932 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2933 target.</p>
2934
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2935<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2936<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2937 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2938 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2939 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2940
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2941<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2942<pre>
2943Test:
2944 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2945 br i1 %cond, label %IfEqual, label %IfUnequal
2946IfEqual:
2947 <a href="#i_ret">ret</a> i32 1
2948IfUnequal:
2949 <a href="#i_ret">ret</a> i32 0
2950</pre>
2951
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2952</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2953
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2954<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2955<div class="doc_subsubsection">
2956 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2957</div>
2958
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2959<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2960
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2961<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2962<pre>
2963 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2964</pre>
2965
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2966<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2967<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2968 several different places. It is a generalization of the '<tt>br</tt>'
2969 instruction, allowing a branch to occur to one of many possible
2970 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2971
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2972<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2973<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2974 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2975 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2976 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2977
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2978<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2979<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2980 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2981 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2982 transferred to the corresponding destination; otherwise, control flow is
2983 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2984
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2985<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2986<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2987 <tt>switch</tt> instruction, this instruction may be code generated in
2988 different ways. For example, it could be generated as a series of chained
2989 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2990
2991<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2992<pre>
2993 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2994 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2995 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2996
2997 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2998 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2999
3000 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3001 switch i32 %val, label %otherwise [ i32 0, label %onzero
3002 i32 1, label %onone
3003 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3004</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3005
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3006</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3007
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3008
3009<!-- _______________________________________________________________________ -->
3010<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3011 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3012</div>
3013
3014<div class="doc_text">
3015
3016<h5>Syntax:</h5>
3017<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3018 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3019</pre>
3020
3021<h5>Overview:</h5>
3022
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3023<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3024 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3025 "<tt>address</tt>". Address must be derived from a <a
3026 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3027
3028<h5>Arguments:</h5>
3029
3030<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3031 rest of the arguments indicate the full set of possible destinations that the
3032 address may point to. Blocks are allowed to occur multiple times in the
3033 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3034
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3035<p>This destination list is required so that dataflow analysis has an accurate
3036 understanding of the CFG.</p>
3037
3038<h5>Semantics:</h5>
3039
3040<p>Control transfers to the block specified in the address argument. All
3041 possible destination blocks must be listed in the label list, otherwise this
3042 instruction has undefined behavior. This implies that jumps to labels
3043 defined in other functions have undefined behavior as well.</p>
3044
3045<h5>Implementation:</h5>
3046
3047<p>This is typically implemented with a jump through a register.</p>
3048
3049<h5>Example:</h5>
3050<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3051 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3052</pre>
3053
3054</div>
3055
3056
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3057<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3058<div class="doc_subsubsection">
3059 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3060</div>
3061
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3062<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3063
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3064<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3065<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3066 &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 Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]3067 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3068</pre>
3069
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3070<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3071<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3072 function, with the possibility of control flow transfer to either the
3073 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3074 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3075 control flow will return to the "normal" label. If the callee (or any
3076 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3077 instruction, control is interrupted and continued at the dynamically nearest
3078 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3079
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3080<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3081<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3082
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3083<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3084 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3085 convention</a> the call should use. If none is specified, the call
3086 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3087
3088 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3089 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3090 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3091
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3092 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3093 function value being invoked. In most cases, this is a direct function
3094 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3095 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3096
3097 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3098 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3099
3100 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3101 signature argument types and parameter attributes. All arguments must be
3102 of <a href="#t_firstclass">first class</a> type. If the function
3103 signature indicates the function accepts a variable number of arguments,
3104 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3105
3106 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3107 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3108
3109 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3110 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3111
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3112 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3113 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3114 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3115</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3116
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3117<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3118<p>This instruction is designed to operate as a standard
3119 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3120 primary difference is that it establishes an association with a label, which
3121 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3122
3123<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3124 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3125 exception. Additionally, this is important for implementation of
3126 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3127
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3128<p>For the purposes of the SSA form, the definition of the value returned by the
3129 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3130 block to the "normal" label. If the callee unwinds then no return value is
3131 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3132
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3133<p>Note that the code generator does not yet completely support unwind, and
3134that the invoke/unwind semantics are likely to change in future versions.</p>
3135
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3136<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3137<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3138 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3139 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3140 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3141 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3142</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3143
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3144</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3145
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3146<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3147
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3148<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3149Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3150
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3151<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3152
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3153<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3154<pre>
3155 unwind
3156</pre>
3157
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3158<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3159<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3160 at the first callee in the dynamic call stack which used
3161 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3162 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3163
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3164<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3165<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3166 immediately halt. The dynamic call stack is then searched for the
3167 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3168 Once found, execution continues at the "exceptional" destination block
3169 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3170 instruction in the dynamic call chain, undefined behavior results.</p>
3171
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3172<p>Note that the code generator does not yet completely support unwind, and
3173that the invoke/unwind semantics are likely to change in future versions.</p>
3174
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3175</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3176
3177<!-- _______________________________________________________________________ -->
3178
3179<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3180Instruction</a> </div>
3181
3182<div class="doc_text">
3183
3184<h5>Syntax:</h5>
3185<pre>
3186 unreachable
3187</pre>
3188
3189<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3190<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3191 instruction is used to inform the optimizer that a particular portion of the
3192 code is not reachable. This can be used to indicate that the code after a
3193 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3194
3195<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3196<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3197
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3198</div>
3199
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3200<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3201<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3202
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3203<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3204
3205<p>Binary operators are used to do most of the computation in a program. They
3206 require two operands of the same type, execute an operation on them, and
3207 produce a single value. The operands might represent multiple data, as is
3208 the case with the <a href="#t_vector">vector</a> data type. The result value
3209 has the same type as its operands.</p>
3210
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3211<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3212
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3213</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3214
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3215<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3216<div class="doc_subsubsection">
3217 <a name="i_add">'<tt>add</tt>' Instruction</a>
3218</div>
3219
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3220<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3221
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3222<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3223<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3224 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3225 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3226 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3227 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3228</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3229
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3230<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3231<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3232
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3233<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3234<p>The two arguments to the '<tt>add</tt>' instruction must
3235 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3236 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3237
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3238<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3239<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3240
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3241<p>If the sum has unsigned overflow, the result returned is the mathematical
3242 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3243
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3244<p>Because LLVM integers use a two's complement representation, this instruction
3245 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3246
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3247<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3248 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3249 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3250 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3251 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3252
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3253<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3254<pre>
3255 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3256</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3257
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3258</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3259
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3260<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3261<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3262 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3263</div>
3264
3265<div class="doc_text">
3266
3267<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3268<pre>
3269 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3270</pre>
3271
3272<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3273<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3274
3275<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3276<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3277 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3278 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3279
3280<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3281<p>The value produced is the floating point sum of the two operands.</p>
3282
3283<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3284<pre>
3285 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3286</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3287
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3288</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3289
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3290<!-- _______________________________________________________________________ -->
3291<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3292 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3293</div>
3294
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3295<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3296
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3297<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3298<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3299 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3300 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3301 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3302 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3303</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3304
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3305<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3306<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3307 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3308
3309<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3310 '<tt>neg</tt>' instruction present in most other intermediate
3311 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3312
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3313<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3314<p>The two arguments to the '<tt>sub</tt>' instruction must
3315 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3316 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3317
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3318<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3319<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3320
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3321<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3322 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3323 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3324
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3325<p>Because LLVM integers use a two's complement representation, this instruction
3326 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3327
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3328<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3329 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3330 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3331 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3332 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3333
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3334<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3335<pre>
3336 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3337 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3338</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3340</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3341
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3342<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3343<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3344 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3345</div>
3346
3347<div class="doc_text">
3348
3349<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3350<pre>
3351 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3352</pre>
3353
3354<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3355<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3356 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3357
3358<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3359 '<tt>fneg</tt>' instruction present in most other intermediate
3360 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3361
3362<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3363<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3364 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3365 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3366
3367<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3368<p>The value produced is the floating point difference of the two operands.</p>
3369
3370<h5>Example:</h5>
3371<pre>
3372 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3373 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3374</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3375
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3376</div>
3377
3378<!-- _______________________________________________________________________ -->
3379<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3380 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3381</div>
3382
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3383<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3384
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3385<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3386<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3387 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3388 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3389 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3390 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3391</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3392
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3393<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3394<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3395
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3396<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3397<p>The two arguments to the '<tt>mul</tt>' instruction must
3398 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3399 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3401<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3402<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3403
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3404<p>If the result of the multiplication has unsigned overflow, the result
3405 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3406 width of the result.</p>
3407
3408<p>Because LLVM integers use a two's complement representation, and the result
3409 is the same width as the operands, this instruction returns the correct
3410 result for both signed and unsigned integers. If a full product
3411 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3412 be sign-extended or zero-extended as appropriate to the width of the full
3413 product.</p>
3414
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3415<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3416 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3417 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3418 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3419 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3420
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3421<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3422<pre>
3423 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3424</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3425
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3426</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3427
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3428<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3429<div class="doc_subsubsection">
3430 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3431</div>
3432
3433<div class="doc_text">
3434
3435<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3436<pre>
3437 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3438</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3439
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3440<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3441<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3442
3443<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3444<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3445 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3446 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3447
3448<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3449<p>The value produced is the floating point product of the two operands.</p>
3450
3451<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452<pre>
3453 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3454</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3455
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3456</div>
3457
3458<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3459<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3460</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3461
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3462<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3463
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3464<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3465<pre>
3466 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3467</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3468
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3469<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3470<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3471
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3472<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3473<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3474 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3475 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3476
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3477<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3478<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3479
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3480<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3481 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3482
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3483<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3484
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3485<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3486<pre>
3487 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3488</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3489
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3490</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3491
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3492<!-- _______________________________________________________________________ -->
3493<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3494</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3495
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3496<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3497
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3498<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3499<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3500 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3501 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3502</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3503
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3504<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3505<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3506
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3507<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3508<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3509 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3510 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3511
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3512<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3513<p>The value produced is the signed integer quotient of the two operands rounded
3514 towards zero.</p>
3515
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3516<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3517 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3518
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3519<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3520 undefined behavior; this is a rare case, but can occur, for example, by doing
3521 a 32-bit division of -2147483648 by -1.</p>
3522
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3523<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3524 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3525 be rounded or if overflow would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3526
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3527<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528<pre>
3529 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3530</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3531
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3532</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3533
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3534<!-- _______________________________________________________________________ -->
3535<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3536Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3537
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3538<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3539
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3540<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3541<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3542 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3543</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3544
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3545<h5>Overview:</h5>
3546<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3547
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3548<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3549<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3550 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3551 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3552
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3553<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3554<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3555
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3556<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3557<pre>
3558 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3559</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3560
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3561</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3562
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3563<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3564<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3565</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3566
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3567<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3568
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3569<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3570<pre>
3571 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3572</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3573
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3574<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3575<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3576 division of its two arguments.</p>
3577
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3578<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3579<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3580 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3581 values. Both arguments must have identical types.</p>
3582
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3583<h5>Semantics:</h5>
3584<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585 This instruction always performs an unsigned division to get the
3586 remainder.</p>
3587
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3588<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3589 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3590
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3591<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3592
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3593<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3594<pre>
3595 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3596</pre>
3597
3598</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3599
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3600<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3601<div class="doc_subsubsection">
3602 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3603</div>
3604
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3605<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3606
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3607<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3608<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3609 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3610</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3611
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3612<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3613<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3614 division of its two operands. This instruction can also take
3615 <a href="#t_vector">vector</a> versions of the values in which case the
3616 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3617
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3618<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3619<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3620 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3621 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3622
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3623<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3624<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3625 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3626 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3627 a value. For more information about the difference,
3628 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3629 Math Forum</a>. For a table of how this is implemented in various languages,
3630 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3631 Wikipedia: modulo operation</a>.</p>
3632
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3633<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3634 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3635
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3636<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3637 Overflow also leads to undefined behavior; this is a rare case, but can
3638 occur, for example, by taking the remainder of a 32-bit division of
3639 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3640 lets srem be implemented using instructions that return both the result of
3641 the division and the remainder.)</p>
3642
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3643<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3644<pre>
3645 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3646</pre>
3647
3648</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3650<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3651<div class="doc_subsubsection">
3652 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3653
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3654<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3655
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3656<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3657<pre>
3658 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3659</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3660
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3661<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3662<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3663 its two operands.</p>
3664
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3665<h5>Arguments:</h5>
3666<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3667 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3668 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3669
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3670<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3671<p>This instruction returns the <i>remainder</i> of a division. The remainder
3672 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3673
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3674<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3675<pre>
3676 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3677</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3678
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3679</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3680
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3681<!-- ======================================================================= -->
3682<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3683Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3684
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3685<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3686
3687<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3688 program. They are generally very efficient instructions and can commonly be
3689 strength reduced from other instructions. They require two operands of the
3690 same type, execute an operation on them, and produce a single value. The
3691 resulting value is the same type as its operands.</p>
3692
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3693</div>
3694
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3695<!-- _______________________________________________________________________ -->
3696<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3697Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3698
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3699<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3700
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3701<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3702<pre>
3703 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3704</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3705
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3706<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3707<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3708 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3709
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3710<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3711<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3712 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3713 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3714
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3715<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3716<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3717 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3718 is (statically or dynamically) negative or equal to or larger than the number
3719 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3720 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3721 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3722
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3723<h5>Example:</h5>
3724<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3725 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3726 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3727 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3728 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3729 &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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3730</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3731
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3732</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3733
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3734<!-- _______________________________________________________________________ -->
3735<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3736Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3737
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3738<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3739
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3740<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3741<pre>
3742 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3743</pre>
3744
3745<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3746<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3747 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3748
3749<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3750<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3751 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3752 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3753
3754<h5>Semantics:</h5>
3755<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3756 significant bits of the result will be filled with zero bits after the shift.
3757 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3758 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3759 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3760 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3761
3762<h5>Example:</h5>
3763<pre>
3764 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3765 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3766 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3767 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3768 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3769 &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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3770</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3771
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3772</div>
3773
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3774<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3775<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3776Instruction</a> </div>
3777<div class="doc_text">
3778
3779<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3780<pre>
3781 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3782</pre>
3783
3784<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3785<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3786 operand shifted to the right a specified number of bits with sign
3787 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3788
3789<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3790<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3791 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3792 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3793
3794<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3795<p>This instruction always performs an arithmetic shift right operation, The
3796 most significant bits of the result will be filled with the sign bit
3797 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3798 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3799 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3800 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3801
3802<h5>Example:</h5>
3803<pre>
3804 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3805 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3806 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3807 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3808 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3809 &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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3810</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3811
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3812</div>
3813
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3814<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3815<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3816Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3817
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3818<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3819
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3820<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3821<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3822 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3823</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3825<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3826<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3827 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3828
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3829<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3830<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3831 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3832 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3833
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3834<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3835<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3836
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3837<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3838 <tbody>
3839 <tr>
3840 <td>In0</td>
3841 <td>In1</td>
3842 <td>Out</td>
3843 </tr>
3844 <tr>
3845 <td>0</td>
3846 <td>0</td>
3847 <td>0</td>
3848 </tr>
3849 <tr>
3850 <td>0</td>
3851 <td>1</td>
3852 <td>0</td>
3853 </tr>
3854 <tr>
3855 <td>1</td>
3856 <td>0</td>
3857 <td>0</td>
3858 </tr>
3859 <tr>
3860 <td>1</td>
3861 <td>1</td>
3862 <td>1</td>
3863 </tr>
3864 </tbody>
3865</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3866
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3867<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3868<pre>
3869 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3870 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3871 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3872</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3873</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3874<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3875<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3876
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3877<div class="doc_text">
3878
3879<h5>Syntax:</h5>
3880<pre>
3881 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3882</pre>
3883
3884<h5>Overview:</h5>
3885<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3886 two operands.</p>
3887
3888<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3889<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3890 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3891 values. Both arguments must have identical types.</p>
3892
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3893<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3894<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3895
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3896<table border="1" cellspacing="0" cellpadding="4">
3897 <tbody>
3898 <tr>
3899 <td>In0</td>
3900 <td>In1</td>
3901 <td>Out</td>
3902 </tr>
3903 <tr>
3904 <td>0</td>
3905 <td>0</td>
3906 <td>0</td>
3907 </tr>
3908 <tr>
3909 <td>0</td>
3910 <td>1</td>
3911 <td>1</td>
3912 </tr>
3913 <tr>
3914 <td>1</td>
3915 <td>0</td>
3916 <td>1</td>
3917 </tr>
3918 <tr>
3919 <td>1</td>
3920 <td>1</td>
3921 <td>1</td>
3922 </tr>
3923 </tbody>
3924</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3926<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3927<pre>
3928 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3929 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3930 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3931</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3932
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3933</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3934
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3935<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3936<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3937Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3938
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3939<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3940
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3941<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3942<pre>
3943 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3944</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3945
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3946<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3947<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3948 its two operands. The <tt>xor</tt> is used to implement the "one's
3949 complement" operation, which is the "~" operator in C.</p>
3950
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3951<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3952<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3953 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3954 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3955
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3956<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3957<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3958
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3959<table border="1" cellspacing="0" cellpadding="4">
3960 <tbody>
3961 <tr>
3962 <td>In0</td>
3963 <td>In1</td>
3964 <td>Out</td>
3965 </tr>
3966 <tr>
3967 <td>0</td>
3968 <td>0</td>
3969 <td>0</td>
3970 </tr>
3971 <tr>
3972 <td>0</td>
3973 <td>1</td>
3974 <td>1</td>
3975 </tr>
3976 <tr>
3977 <td>1</td>
3978 <td>0</td>
3979 <td>1</td>
3980 </tr>
3981 <tr>
3982 <td>1</td>
3983 <td>1</td>
3984 <td>0</td>
3985 </tr>
3986 </tbody>
3987</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3989<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3990<pre>
3991 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3992 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3993 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3994 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3995</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3996
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3997</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3998
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3999<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4000<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4001 <a name="vectorops">Vector Operations</a>
4002</div>
4003
4004<div class="doc_text">
4005
4006<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4007 target-independent manner. These instructions cover the element-access and
4008 vector-specific operations needed to process vectors effectively. While LLVM
4009 does directly support these vector operations, many sophisticated algorithms
4010 will want to use target-specific intrinsics to take full advantage of a
4011 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4012
4013</div>
4014
4015<!-- _______________________________________________________________________ -->
4016<div class="doc_subsubsection">
4017 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4018</div>
4019
4020<div class="doc_text">
4021
4022<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4023<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4024 &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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4025</pre>
4026
4027<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4028<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4029 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4030
4031
4032<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4033<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4034 of <a href="#t_vector">vector</a> type. The second operand is an index
4035 indicating the position from which to extract the element. The index may be
4036 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4037
4038<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4039<p>The result is a scalar of the same type as the element type of
4040 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4041 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4042 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4043
4044<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4045<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4046 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4047</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4048
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4049</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4050
4051<!-- _______________________________________________________________________ -->
4052<div class="doc_subsubsection">
4053 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4054</div>
4055
4056<div class="doc_text">
4057
4058<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4059<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4060 &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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4061</pre>
4062
4063<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4064<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4065 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4066
4067<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4068<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4069 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4070 whose type must equal the element type of the first operand. The third
4071 operand is an index indicating the position at which to insert the value.
4072 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4073
4074<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4075<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4076 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4077 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4078 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4079
4080<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4081<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4082 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4083</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4084
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4085</div>
4086
4087<!-- _______________________________________________________________________ -->
4088<div class="doc_subsubsection">
4089 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4090</div>
4091
4092<div class="doc_text">
4093
4094<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4095<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4096 &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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4097</pre>
4098
4099<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4100<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4101 from two input vectors, returning a vector with the same element type as the
4102 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4103
4104<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4105<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4106 with types that match each other. The third argument is a shuffle mask whose
4107 element type is always 'i32'. The result of the instruction is a vector
4108 whose length is the same as the shuffle mask and whose element type is the
4109 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4110
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4111<p>The shuffle mask operand is required to be a constant vector with either
4112 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4113
4114<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4115<p>The elements of the two input vectors are numbered from left to right across
4116 both of the vectors. The shuffle mask operand specifies, for each element of
4117 the result vector, which element of the two input vectors the result element
4118 gets. The element selector may be undef (meaning "don't care") and the
4119 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4120
4121<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4122<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4123 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4124 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4125 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerca86e162006-12-31 07:07:53 +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> - Identity shuffle.
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4127 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4128 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4129 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4130 &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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4131</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4132
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4133</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4134
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4135<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4136<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4137 <a name="aggregateops">Aggregate Operations</a>
4138</div>
4139
4140<div class="doc_text">
4141
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4142<p>LLVM supports several instructions for working with
4143 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4144
4145</div>
4146
4147<!-- _______________________________________________________________________ -->
4148<div class="doc_subsubsection">
4149 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4150</div>
4151
4152<div class="doc_text">
4153
4154<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4155<pre>
4156 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4157</pre>
4158
4159<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4160<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4161 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4162
4163<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4164<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4165 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4166 <a href="#t_array">array</a> type. The operands are constant indices to
4167 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4168 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4169
4170<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4171<p>The result is the value at the position in the aggregate specified by the
4172 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4173
4174<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4175<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4176 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4177</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4178
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4179</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4180
4181<!-- _______________________________________________________________________ -->
4182<div class="doc_subsubsection">
4183 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4184</div>
4185
4186<div class="doc_text">
4187
4188<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4189<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4190 &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 Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4191</pre>
4192
4193<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4194<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4195 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4196
4197<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4198<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4199 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4200 <a href="#t_array">array</a> type. The second operand is a first-class
4201 value to insert. The following operands are constant indices indicating
4202 the position at which to insert the value in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4203 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4204 value to insert must have the same type as the value identified by the
4205 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4206
4207<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4208<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4209 that of <tt>val</tt> except that the value at the position specified by the
4210 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4211
4212<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4213<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4214 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4215 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4216</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4217
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4218</div>
4219
4220
4221<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4222<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4223 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4224</div>
4225
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4226<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4227
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4228<p>A key design point of an SSA-based representation is how it represents
4229 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4230 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4231 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4232
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4233</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4234
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4235<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4236<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4237 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4238</div>
4239
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4240<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4241
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4242<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4243<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4244 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4245</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4246
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4247<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4248<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4249 currently executing function, to be automatically released when this function
4250 returns to its caller. The object is always allocated in the generic address
4251 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4252
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4253<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4254<p>The '<tt>alloca</tt>' instruction
4255 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4256 runtime stack, returning a pointer of the appropriate type to the program.
4257 If "NumElements" is specified, it is the number of elements allocated,
4258 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4259 specified, the value result of the allocation is guaranteed to be aligned to
4260 at least that boundary. If not specified, or if zero, the target can choose
4261 to align the allocation on any convenient boundary compatible with the
4262 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4263
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4264<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4265
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4266<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4267<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4268 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4269 memory is automatically released when the function returns. The
4270 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4271 variables that must have an address available. When the function returns
4272 (either with the <tt><a href="#i_ret">ret</a></tt>
4273 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4274 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4275
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4276<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4277<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4278 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4279 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4280 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4281 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4282</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4283
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4284</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4285
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4286<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4287<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4288Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4289
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4290<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4291
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4292<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4293<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4294 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4295 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4296 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4297</pre>
4298
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4299<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4300<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4301
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4302<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4303<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4304 from which to load. The pointer must point to
4305 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4306 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4307 number or order of execution of this <tt>load</tt> with other <a
4308 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4309
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4310<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4311 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4312 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4313 alignment for the target. It is the responsibility of the code emitter to
4314 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4315 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4316 produce less efficient code. An alignment of 1 is always safe.</p>
4317
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4318<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4319 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4320 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4321 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4322 and code generator that this load is not expected to be reused in the cache.
4323 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4324 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4325
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4326<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4327<p>The location of memory pointed to is loaded. If the value being loaded is of
4328 scalar type then the number of bytes read does not exceed the minimum number
4329 of bytes needed to hold all bits of the type. For example, loading an
4330 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4331 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4332 is undefined if the value was not originally written using a store of the
4333 same type.</p>
4334
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4335<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4336<pre>
4337 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4338 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4339 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4340</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4341
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4342</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4343
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4344<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4345<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4346Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4347
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4348<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4349
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4350<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4351<pre>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4352 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4353 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 Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4354</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4355
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4356<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4357<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4358
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4359<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4360<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4361 and an address at which to store it. The type of the
4362 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4363 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4364 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4365 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4366 order of execution of this <tt>store</tt> with other <a
4367 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4368
4369<p>The optional constant "align" argument specifies the alignment of the
4370 operation (that is, the alignment of the memory address). A value of 0 or an
4371 omitted "align" argument means that the operation has the preferential
4372 alignment for the target. It is the responsibility of the code emitter to
4373 ensure that the alignment information is correct. Overestimating the
4374 alignment results in an undefined behavior. Underestimating the alignment may
4375 produce less efficient code. An alignment of 1 is always safe.</p>
4376
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4377<p>The optional !nontemporal metadata must reference a single metatadata
4378 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4379 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4380 instruction tells the optimizer and code generator that this load is
4381 not expected to be reused in the cache. The code generator may
4382 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4383 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4384
4385
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4386<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4387<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4388 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4389 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4390 does not exceed the minimum number of bytes needed to hold all bits of the
4391 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4392 writing a value of a type like <tt>i20</tt> with a size that is not an
4393 integral number of bytes, it is unspecified what happens to the extra bits
4394 that do not belong to the type, but they will typically be overwritten.</p>
4395
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4396<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4397<pre>
4398 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4399 store i32 3, i32* %ptr <i>; yields {void}</i>
4400 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4401</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4402
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4403</div>
4404
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4405<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4406<div class="doc_subsubsection">
4407 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4408</div>
4409
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4410<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4411
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4412<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4413<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4414 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4415 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4416</pre>
4417
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4418<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4419<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4420 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4421 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4422
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4423<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4424<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4425 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4426 elements of the aggregate object are indexed. The interpretation of each
4427 index is dependent on the type being indexed into. The first index always
4428 indexes the pointer value given as the first argument, the second index
4429 indexes a value of the type pointed to (not necessarily the value directly
4430 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4431 indexed into must be a pointer value, subsequent types can be arrays,
4432 vectors, structs and unions. Note that subsequent types being indexed into
4433 can never be pointers, since that would require loading the pointer before
4434 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4435
4436<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4437 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4438 integer <b>constants</b> are allowed. When indexing into an array, pointer
4439 or vector, integers of any width are allowed, and they are not required to be
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4440 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4441
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4442<p>For example, let's consider a C code fragment and how it gets compiled to
4443 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4444
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4445<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4446<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4447struct RT {
4448 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4449 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4450 char C;
4451};
4452struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4453 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4454 double Y;
4455 struct RT Z;
4456};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4457
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4458int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4459 return &amp;s[1].Z.B[5][13];
4460}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4461</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4462</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4463
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4464<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4465
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4466<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4467<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4468%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4469%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4470
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4471define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4472entry:
4473 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4474 ret i32* %reg
4475}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4476</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4477</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4478
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4479<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4480<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4481 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4482 }</tt>' type, a structure. The second index indexes into the third element
4483 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4484 i8 }</tt>' type, another structure. The third index indexes into the second
4485 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4486 array. The two dimensions of the array are subscripted into, yielding an
4487 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4488 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4489
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4490<p>Note that it is perfectly legal to index partially through a structure,
4491 returning a pointer to an inner element. Because of this, the LLVM code for
4492 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4493
4494<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4495 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4496 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4497 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4498 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4499 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4500 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4501 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4502 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4503</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4504
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4505<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4506 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4507 base pointer is not an <i>in bounds</i> address of an allocated object,
4508 or if any of the addresses that would be formed by successive addition of
4509 the offsets implied by the indices to the base address with infinitely
4510 precise arithmetic are not an <i>in bounds</i> address of that allocated
4511 object. The <i>in bounds</i> addresses for an allocated object are all
4512 the addresses that point into the object, plus the address one byte past
4513 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4514
4515<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4516 the base address with silently-wrapping two's complement arithmetic, and
4517 the result value of the <tt>getelementptr</tt> may be outside the object
4518 pointed to by the base pointer. The result value may not necessarily be
4519 used to access memory though, even if it happens to point into allocated
4520 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4521 section for more information.</p>
4522
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4523<p>The getelementptr instruction is often confusing. For some more insight into
4524 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4525
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4526<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4527<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4528 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4529 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4530 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4531 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4532 <i>; yields i8*:eptr</i>
4533 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4534 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4535 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4536</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4537
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4538</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4539
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4540<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4541<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4542</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4543
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4544<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4545
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4546<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4547 which all take a single operand and a type. They perform various bit
4548 conversions on the operand.</p>
4549
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4550</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4551
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4552<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4553<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4554 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4555</div>
4556<div class="doc_text">
4557
4558<h5>Syntax:</h5>
4559<pre>
4560 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4561</pre>
4562
4563<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4564<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4565 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4566
4567<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4568<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4569 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4570 size and type of the result, which must be
4571 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4572 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4573 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4574
4575<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4576<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4577 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4578 source size must be larger than the destination size, <tt>trunc</tt> cannot
4579 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4580
4581<h5>Example:</h5>
4582<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4583 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4584 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4585 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4586</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4587
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4588</div>
4589
4590<!-- _______________________________________________________________________ -->
4591<div class="doc_subsubsection">
4592 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4593</div>
4594<div class="doc_text">
4595
4596<h5>Syntax:</h5>
4597<pre>
4598 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4599</pre>
4600
4601<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4602<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4603 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4604
4605
4606<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4607<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4608 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4609 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4610 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4611 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4612
4613<h5>Semantics:</h5>
4614<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4615 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4616
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4617<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4618
4619<h5>Example:</h5>
4620<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4621 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4622 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4623</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4624
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4625</div>
4626
4627<!-- _______________________________________________________________________ -->
4628<div class="doc_subsubsection">
4629 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4630</div>
4631<div class="doc_text">
4632
4633<h5>Syntax:</h5>
4634<pre>
4635 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4636</pre>
4637
4638<h5>Overview:</h5>
4639<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4640
4641<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4642<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4643 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4644 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4645 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4646 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4647
4648<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4649<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4650 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4651 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4652
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4653<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4654
4655<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4656<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4657 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4658 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4659</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4660
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4661</div>
4662
4663<!-- _______________________________________________________________________ -->
4664<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4665 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4666</div>
4667
4668<div class="doc_text">
4669
4670<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4671<pre>
4672 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4673</pre>
4674
4675<h5>Overview:</h5>
4676<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4677 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4678
4679<h5>Arguments:</h5>
4680<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4681 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4682 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4683 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4684 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4685
4686<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4687<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4688 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4689 <a href="#t_floating">floating point</a> type. If the value cannot fit
4690 within the destination type, <tt>ty2</tt>, then the results are
4691 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4692
4693<h5>Example:</h5>
4694<pre>
4695 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4696 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4697</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4698
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4699</div>
4700
4701<!-- _______________________________________________________________________ -->
4702<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4703 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4704</div>
4705<div class="doc_text">
4706
4707<h5>Syntax:</h5>
4708<pre>
4709 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4710</pre>
4711
4712<h5>Overview:</h5>
4713<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4714 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4715
4716<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4717<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4718 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4719 a <a href="#t_floating">floating point</a> type to cast it to. The source
4720 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4721
4722<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4723<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4724 <a href="#t_floating">floating point</a> type to a larger
4725 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4726 used to make a <i>no-op cast</i> because it always changes bits. Use
4727 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4728
4729<h5>Example:</h5>
4730<pre>
4731 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4732 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4733</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4734
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4735</div>
4736
4737<!-- _______________________________________________________________________ -->
4738<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4739 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4740</div>
4741<div class="doc_text">
4742
4743<h5>Syntax:</h5>
4744<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4745 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4746</pre>
4747
4748<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4749<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4750 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4751
4752<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4753<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4754 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4755 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4756 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4757 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4758
4759<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4760<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4761 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4762 towards zero) unsigned integer value. If the value cannot fit
4763 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4764
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4765<h5>Example:</h5>
4766<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4767 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4768 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4769 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4770</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4771
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4772</div>
4773
4774<!-- _______________________________________________________________________ -->
4775<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4776 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4777</div>
4778<div class="doc_text">
4779
4780<h5>Syntax:</h5>
4781<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4782 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4783</pre>
4784
4785<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4786<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4787 <a href="#t_floating">floating point</a> <tt>value</tt> to
4788 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4789
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4790<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4791<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4792 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4793 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4794 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4795 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4796
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4797<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4798<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4799 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4800 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4801 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4802
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4803<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4804<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4805 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4806 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4807 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4808</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4809
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4810</div>
4811
4812<!-- _______________________________________________________________________ -->
4813<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4814 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4815</div>
4816<div class="doc_text">
4817
4818<h5>Syntax:</h5>
4819<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4820 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4821</pre>
4822
4823<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4824<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4825 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4826
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4827<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4828<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4829 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4830 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4831 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4832 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4833
4834<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4835<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4836 integer quantity and converts it to the corresponding floating point
4837 value. If the value cannot fit in the floating point value, the results are
4838 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4839
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4840<h5>Example:</h5>
4841<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4842 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4843 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4844</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4845
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4846</div>
4847
4848<!-- _______________________________________________________________________ -->
4849<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4850 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4851</div>
4852<div class="doc_text">
4853
4854<h5>Syntax:</h5>
4855<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4856 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4857</pre>
4858
4859<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4860<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4861 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4862
4863<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4864<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4865 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4866 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4867 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4868 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4869
4870<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4871<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4872 quantity and converts it to the corresponding floating point value. If the
4873 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4874
4875<h5>Example:</h5>
4876<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4877 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4878 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4879</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4880
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4881</div>
4882
4883<!-- _______________________________________________________________________ -->
4884<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4885 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4886</div>
4887<div class="doc_text">
4888
4889<h5>Syntax:</h5>
4890<pre>
4891 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4892</pre>
4893
4894<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4895<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4896 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4897
4898<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4899<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4900 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4901 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4902
4903<h5>Semantics:</h5>
4904<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4905 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4906 truncating or zero extending that value to the size of the integer type. If
4907 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4908 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4909 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4910 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4911
4912<h5>Example:</h5>
4913<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4914 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4915 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4916</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4917
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4918</div>
4919
4920<!-- _______________________________________________________________________ -->
4921<div class="doc_subsubsection">
4922 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4923</div>
4924<div class="doc_text">
4925
4926<h5>Syntax:</h5>
4927<pre>
4928 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4929</pre>
4930
4931<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4932<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4933 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4934
4935<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4936<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4937 value to cast, and a type to cast it to, which must be a
4938 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4939
4940<h5>Semantics:</h5>
4941<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4942 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4943 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4944 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4945 than the size of a pointer then a zero extension is done. If they are the
4946 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4947
4948<h5>Example:</h5>
4949<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4950 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4951 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4952 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4953</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4954
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4955</div>
4956
4957<!-- _______________________________________________________________________ -->
4958<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4959 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4960</div>
4961<div class="doc_text">
4962
4963<h5>Syntax:</h5>
4964<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4965 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4966</pre>
4967
4968<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4969<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4970 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4971
4972<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4973<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4974 non-aggregate first class value, and a type to cast it to, which must also be
4975 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4976 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4977 identical. If the source type is a pointer, the destination type must also be
4978 a pointer. This instruction supports bitwise conversion of vectors to
4979 integers and to vectors of other types (as long as they have the same
4980 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4981
4982<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4983<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4984 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4985 this conversion. The conversion is done as if the <tt>value</tt> had been
4986 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4987 be converted to other pointer types with this instruction. To convert
4988 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4989 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4990
4991<h5>Example:</h5>
4992<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4993 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4994 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4995 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4996</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4997
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4998</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4999
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5000<!-- ======================================================================= -->
5001<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5002
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5003<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5004
5005<p>The instructions in this category are the "miscellaneous" instructions, which
5006 defy better classification.</p>
5007
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5008</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5009
5010<!-- _______________________________________________________________________ -->
5011<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5012</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5013
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5014<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5015
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5016<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5017<pre>
5018 &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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5019</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5020
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5021<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5022<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5023 boolean values based on comparison of its two integer, integer vector, or
5024 pointer operands.</p>
5025
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5026<h5>Arguments:</h5>
5027<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5028 the condition code indicating the kind of comparison to perform. It is not a
5029 value, just a keyword. The possible condition code are:</p>
5030
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5031<ol>
5032 <li><tt>eq</tt>: equal</li>
5033 <li><tt>ne</tt>: not equal </li>
5034 <li><tt>ugt</tt>: unsigned greater than</li>
5035 <li><tt>uge</tt>: unsigned greater or equal</li>
5036 <li><tt>ult</tt>: unsigned less than</li>
5037 <li><tt>ule</tt>: unsigned less or equal</li>
5038 <li><tt>sgt</tt>: signed greater than</li>
5039 <li><tt>sge</tt>: signed greater or equal</li>
5040 <li><tt>slt</tt>: signed less than</li>
5041 <li><tt>sle</tt>: signed less or equal</li>
5042</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5043
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5044<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5045 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5046 typed. They must also be identical types.</p>
5047
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5048<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5049<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5050 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5051 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5052 result, as follows:</p>
5053
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5054<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5055 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5056 <tt>false</tt> otherwise. No sign interpretation is necessary or
5057 performed.</li>
5058
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5059 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5060 <tt>false</tt> otherwise. No sign interpretation is necessary or
5061 performed.</li>
5062
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5063 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5064 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5065
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5066 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5067 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5068 to <tt>op2</tt>.</li>
5069
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5070 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5072
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5073 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5074 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5075
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5076 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5077 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5078
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5079 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5081 to <tt>op2</tt>.</li>
5082
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5083 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5084 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5085
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5086 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5087 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5088</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5089
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5090<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5091 values are compared as if they were integers.</p>
5092
5093<p>If the operands are integer vectors, then they are compared element by
5094 element. The result is an <tt>i1</tt> vector with the same number of elements
5095 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5096
5097<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5098<pre>
5099 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5100 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5101 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5102 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5103 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5104 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5105</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5106
5107<p>Note that the code generator does not yet support vector types with
5108 the <tt>icmp</tt> instruction.</p>
5109
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5110</div>
5111
5112<!-- _______________________________________________________________________ -->
5113<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5114</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5115
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5116<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5117
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5118<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5119<pre>
5120 &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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5121</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5122
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5123<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5124<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5125 values based on comparison of its operands.</p>
5126
5127<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5128(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5129
5130<p>If the operands are floating point vectors, then the result type is a vector
5131 of boolean with the same number of elements as the operands being
5132 compared.</p>
5133
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5134<h5>Arguments:</h5>
5135<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5136 the condition code indicating the kind of comparison to perform. It is not a
5137 value, just a keyword. The possible condition code are:</p>
5138
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5139<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5140 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5141 <li><tt>oeq</tt>: ordered and equal</li>
5142 <li><tt>ogt</tt>: ordered and greater than </li>
5143 <li><tt>oge</tt>: ordered and greater than or equal</li>
5144 <li><tt>olt</tt>: ordered and less than </li>
5145 <li><tt>ole</tt>: ordered and less than or equal</li>
5146 <li><tt>one</tt>: ordered and not equal</li>
5147 <li><tt>ord</tt>: ordered (no nans)</li>
5148 <li><tt>ueq</tt>: unordered or equal</li>
5149 <li><tt>ugt</tt>: unordered or greater than </li>
5150 <li><tt>uge</tt>: unordered or greater than or equal</li>
5151 <li><tt>ult</tt>: unordered or less than </li>
5152 <li><tt>ule</tt>: unordered or less than or equal</li>
5153 <li><tt>une</tt>: unordered or not equal</li>
5154 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5155 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5156</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5157
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5158<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5159 <i>unordered</i> means that either operand may be a QNAN.</p>
5160
5161<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5162 a <a href="#t_floating">floating point</a> type or
5163 a <a href="#t_vector">vector</a> of floating point type. They must have
5164 identical types.</p>
5165
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5166<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5167<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5168 according to the condition code given as <tt>cond</tt>. If the operands are
5169 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5170 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5171 follows:</p>
5172
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5173<ol>
5174 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5175
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5176 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5177 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5178
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5179 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5180 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5181
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5182 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5183 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5184
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5185 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5186 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5187
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5188 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5189 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5190
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5191 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5192 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5193
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5194 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5195
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5196 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5197 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5198
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5199 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5200 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5201
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5202 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5203 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5204
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5205 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5206 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5207
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5208 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5209 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5210
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5211 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5212 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5213
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5214 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5215
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5216 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5217</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5218
5219<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5220<pre>
5221 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5222 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5223 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5224 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5225</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5226
5227<p>Note that the code generator does not yet support vector types with
5228 the <tt>fcmp</tt> instruction.</p>
5229
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5230</div>
5231
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5232<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5233<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5234 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5235</div>
5236
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5237<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5238
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5239<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5240<pre>
5241 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5242</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5243
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5244<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5245<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5246 SSA graph representing the function.</p>
5247
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5248<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5249<p>The type of the incoming values is specified with the first type field. After
5250 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5251 one pair for each predecessor basic block of the current block. Only values
5252 of <a href="#t_firstclass">first class</a> type may be used as the value
5253 arguments to the PHI node. Only labels may be used as the label
5254 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5255
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5256<p>There must be no non-phi instructions between the start of a basic block and
5257 the PHI instructions: i.e. PHI instructions must be first in a basic
5258 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5259
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5260<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5261 occur on the edge from the corresponding predecessor block to the current
5262 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5263 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5264
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5265<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5266<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5267 specified by the pair corresponding to the predecessor basic block that
5268 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5269
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5270<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5271<pre>
5272Loop: ; Infinite loop that counts from 0 on up...
5273 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5274 %nextindvar = add i32 %indvar, 1
5275 br label %Loop
5276</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5277
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5278</div>
5279
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5280<!-- _______________________________________________________________________ -->
5281<div class="doc_subsubsection">
5282 <a name="i_select">'<tt>select</tt>' Instruction</a>
5283</div>
5284
5285<div class="doc_text">
5286
5287<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5288<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5289 &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>
5290
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5291 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5292</pre>
5293
5294<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5295<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5296 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5297
5298
5299<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5300<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5301 values indicating the condition, and two values of the
5302 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5303 vectors and the condition is a scalar, then entire vectors are selected, not
5304 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5305
5306<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5307<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5308 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5309
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5310<p>If the condition is a vector of i1, then the value arguments must be vectors
5311 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5312
5313<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5314<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5315 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5316</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5317
5318<p>Note that the code generator does not yet support conditions
5319 with vector type.</p>
5320
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5321</div>
5322
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5323<!-- _______________________________________________________________________ -->
5324<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5325 <a name="i_call">'<tt>call</tt>' Instruction</a>
5326</div>
5327
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5328<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5329
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5330<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5331<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5332 &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 Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5333</pre>
5334
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5335<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5336<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5337
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5338<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5339<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5340
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5341<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5342 <li>The optional "tail" marker indicates that the callee function does not
5343 access any allocas or varargs in the caller. Note that calls may be
5344 marked "tail" even if they do not occur before
5345 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5346 present, the function call is eligible for tail call optimization,
5347 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5348 optimized into a jump</a>. The code generator may optimize calls marked
5349 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5350 sibling call optimization</a> when the caller and callee have
5351 matching signatures, or 2) forced tail call optimization when the
5352 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5353 <ul>
5354 <li>Caller and callee both have the calling
5355 convention <tt>fastcc</tt>.</li>
5356 <li>The call is in tail position (ret immediately follows call and ret
5357 uses value of call or is void).</li>
5358 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5359 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5360 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5361 constraints are met.</a></li>
5362 </ul>
5363 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5364
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5365 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5366 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5367 defaults to using C calling conventions. The calling convention of the
5368 call must match the calling convention of the target function, or else the
5369 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5370
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5371 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5372 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5373 '<tt>inreg</tt>' attributes are valid here.</li>
5374
5375 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5376 type of the return value. Functions that return no value are marked
5377 <tt><a href="#t_void">void</a></tt>.</li>
5378
5379 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5380 being invoked. The argument types must match the types implied by this
5381 signature. This type can be omitted if the function is not varargs and if
5382 the function type does not return a pointer to a function.</li>
5383
5384 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5385 be invoked. In most cases, this is a direct function invocation, but
5386 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5387 to function value.</li>
5388
5389 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5390 signature argument types and parameter attributes. All arguments must be
5391 of <a href="#t_firstclass">first class</a> type. If the function
5392 signature indicates the function accepts a variable number of arguments,
5393 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5394
5395 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5396 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5397 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5398</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5399
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5400<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5401<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5402 a specified function, with its incoming arguments bound to the specified
5403 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5404 function, control flow continues with the instruction after the function
5405 call, and the return value of the function is bound to the result
5406 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5407
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5408<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5409<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5410 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5411 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5412 %X = tail call i32 @foo() <i>; yields i32</i>
5413 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5414 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5415
5416 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5417 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5418 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5419 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5420 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5421 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5422</pre>
5423
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5424<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5425standard C99 library as being the C99 library functions, and may perform
5426optimizations or generate code for them under that assumption. This is
5427something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5428freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5429
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5430</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5431
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5432<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5433<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5434 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5435</div>
5436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5437<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5438
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5439<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5440<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5441 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5442</pre>
5443
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5444<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5445<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5446 the "variable argument" area of a function call. It is used to implement the
5447 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5448
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5449<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5450<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5451 argument. It returns a value of the specified argument type and increments
5452 the <tt>va_list</tt> to point to the next argument. The actual type
5453 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5454
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5455<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5456<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5457 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5458 to the next argument. For more information, see the variable argument
5459 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5460
5461<p>It is legal for this instruction to be called in a function which does not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5462 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5463 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5464
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5465<p><tt>va_arg</tt> is an LLVM instruction instead of
5466 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5467 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5468
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5469<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5470<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5471
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5472<p>Note that the code generator does not yet fully support va_arg on many
5473 targets. Also, it does not currently support va_arg with aggregate types on
5474 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5475
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5476</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5477
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5478<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5479<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5480<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5481
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5482<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5483
5484<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5485 well known names and semantics and are required to follow certain
5486 restrictions. Overall, these intrinsics represent an extension mechanism for
5487 the LLVM language that does not require changing all of the transformations
5488 in LLVM when adding to the language (or the bitcode reader/writer, the
5489 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5490
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5491<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5492 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5493 begin with this prefix. Intrinsic functions must always be external
5494 functions: you cannot define the body of intrinsic functions. Intrinsic
5495 functions may only be used in call or invoke instructions: it is illegal to
5496 take the address of an intrinsic function. Additionally, because intrinsic
5497 functions are part of the LLVM language, it is required if any are added that
5498 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5499
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5500<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5501 family of functions that perform the same operation but on different data
5502 types. Because LLVM can represent over 8 million different integer types,
5503 overloading is used commonly to allow an intrinsic function to operate on any
5504 integer type. One or more of the argument types or the result type can be
5505 overloaded to accept any integer type. Argument types may also be defined as
5506 exactly matching a previous argument's type or the result type. This allows
5507 an intrinsic function which accepts multiple arguments, but needs all of them
5508 to be of the same type, to only be overloaded with respect to a single
5509 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5510
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5511<p>Overloaded intrinsics will have the names of its overloaded argument types
5512 encoded into its function name, each preceded by a period. Only those types
5513 which are overloaded result in a name suffix. Arguments whose type is matched
5514 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5515 can take an integer of any width and returns an integer of exactly the same
5516 integer width. This leads to a family of functions such as
5517 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5518 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5519 suffix is required. Because the argument's type is matched against the return
5520 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5521
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5522<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5523 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5524
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5525</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5526
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5527<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5528<div class="doc_subsection">
5529 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5530</div>
5531
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5532<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5533
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5534<p>Variable argument support is defined in LLVM with
5535 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5536 intrinsic functions. These functions are related to the similarly named
5537 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5538
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5539<p>All of these functions operate on arguments that use a target-specific value
5540 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5541 not define what this type is, so all transformations should be prepared to
5542 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5543
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5544<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5545 instruction and the variable argument handling intrinsic functions are
5546 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5547
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5548<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5549<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5550define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5551 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5552 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5553 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5554 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5555
5556 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5557 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5558
5559 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5560 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5561 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5562 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5563 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5564
5565 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5566 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5567 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5568}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5569
5570declare void @llvm.va_start(i8*)
5571declare void @llvm.va_copy(i8*, i8*)
5572declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5573</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5574</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5575
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5576</div>
5577
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5578<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5579<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5580 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5581</div>
5582
5583
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5584<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5585
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5586<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5587<pre>
5588 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5589</pre>
5590
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5591<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5592<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5593 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5594
5595<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5596<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5597
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5598<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5599<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5600 macro available in C. In a target-dependent way, it initializes
5601 the <tt>va_list</tt> element to which the argument points, so that the next
5602 call to <tt>va_arg</tt> will produce the first variable argument passed to
5603 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5604 need to know the last argument of the function as the compiler can figure
5605 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5606
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5607</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5608
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5609<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5610<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5611 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5612</div>
5613
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5614<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5615
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5616<h5>Syntax:</h5>
5617<pre>
5618 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5619</pre>
5620
5621<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5622<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5623 which has been initialized previously
5624 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5625 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5626
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5627<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5628<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5629
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5630<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5631<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5632 macro available in C. In a target-dependent way, it destroys
5633 the <tt>va_list</tt> element to which the argument points. Calls
5634 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5635 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5636 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5637
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5638</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5639
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5640<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5641<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5642 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5643</div>
5644
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5645<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5646
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5647<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5648<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5649 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5650</pre>
5651
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5652<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5653<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5654 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5655
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5656<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5657<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5658 The second argument is a pointer to a <tt>va_list</tt> element to copy
5659 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5660
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5661<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5662<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5663 macro available in C. In a target-dependent way, it copies the
5664 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5665 element. This intrinsic is necessary because
5666 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5667 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5668
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5669</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5670
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5671<!-- ======================================================================= -->
5672<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5673 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5674</div>
5675
5676<div class="doc_text">
5677
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5678<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5679Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5680intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5681roots on the stack</a>, as well as garbage collector implementations that
5682require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5683barriers. Front-ends for type-safe garbage collected languages should generate
5684these intrinsics to make use of the LLVM garbage collectors. For more details,
5685see <a href="GarbageCollection.html">Accurate Garbage Collection with
5686LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5687
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5688<p>The garbage collection intrinsics only operate on objects in the generic
5689 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5690
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5691</div>
5692
5693<!-- _______________________________________________________________________ -->
5694<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5695 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5696</div>
5697
5698<div class="doc_text">
5699
5700<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5701<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5702 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5703</pre>
5704
5705<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5706<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5707 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5708
5709<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5710<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5711 root pointer. The second pointer (which must be either a constant or a
5712 global value address) contains the meta-data to be associated with the
5713 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5714
5715<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5716<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5717 location. At compile-time, the code generator generates information to allow
5718 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5719 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5720 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5721
5722</div>
5723
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5724<!-- _______________________________________________________________________ -->
5725<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5726 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5727</div>
5728
5729<div class="doc_text">
5730
5731<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5732<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5733 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5734</pre>
5735
5736<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5737<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5738 locations, allowing garbage collector implementations that require read
5739 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5740
5741<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5742<p>The second argument is the address to read from, which should be an address
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5743 allocated from the garbage collector. The first object is a pointer to the
5744 start of the referenced object, if needed by the language runtime (otherwise
5745 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5746
5747<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5748<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5749 instruction, but may be replaced with substantially more complex code by the
5750 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5751 may only be used in a function which <a href="#gc">specifies a GC
5752 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5753
5754</div>
5755
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5756<!-- _______________________________________________________________________ -->
5757<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5758 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5759</div>
5760
5761<div class="doc_text">
5762
5763<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5764<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5765 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5766</pre>
5767
5768<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5769<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5770 locations, allowing garbage collector implementations that require write
5771 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5772
5773<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5774<p>The first argument is the reference to store, the second is the start of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5775 object to store it to, and the third is the address of the field of Obj to
5776 store to. If the runtime does not require a pointer to the object, Obj may
5777 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5778
5779<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5780<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5781 instruction, but may be replaced with substantially more complex code by the
5782 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5783 may only be used in a function which <a href="#gc">specifies a GC
5784 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5785
5786</div>
5787
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5788<!-- ======================================================================= -->
5789<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5790 <a name="int_codegen">Code Generator Intrinsics</a>
5791</div>
5792
5793<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5794
5795<p>These intrinsics are provided by LLVM to expose special features that may
5796 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5797
5798</div>
5799
5800<!-- _______________________________________________________________________ -->
5801<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5802 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5803</div>
5804
5805<div class="doc_text">
5806
5807<h5>Syntax:</h5>
5808<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5809 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5810</pre>
5811
5812<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5813<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5814 target-specific value indicating the return address of the current function
5815 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5816
5817<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5818<p>The argument to this intrinsic indicates which function to return the address
5819 for. Zero indicates the calling function, one indicates its caller, etc.
5820 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5821
5822<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5823<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5824 indicating the return address of the specified call frame, or zero if it
5825 cannot be identified. The value returned by this intrinsic is likely to be
5826 incorrect or 0 for arguments other than zero, so it should only be used for
5827 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5828
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5829<p>Note that calling this intrinsic does not prevent function inlining or other
5830 aggressive transformations, so the value returned may not be that of the
5831 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5832
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5833</div>
5834
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5835<!-- _______________________________________________________________________ -->
5836<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5837 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5838</div>
5839
5840<div class="doc_text">
5841
5842<h5>Syntax:</h5>
5843<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5844 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5845</pre>
5846
5847<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5848<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5849 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5850
5851<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5852<p>The argument to this intrinsic indicates which function to return the frame
5853 pointer for. Zero indicates the calling function, one indicates its caller,
5854 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5855
5856<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5857<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5858 indicating the frame address of the specified call frame, or zero if it
5859 cannot be identified. The value returned by this intrinsic is likely to be
5860 incorrect or 0 for arguments other than zero, so it should only be used for
5861 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5862
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5863<p>Note that calling this intrinsic does not prevent function inlining or other
5864 aggressive transformations, so the value returned may not be that of the
5865 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5866
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5867</div>
5868
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5869<!-- _______________________________________________________________________ -->
5870<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5871 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5872</div>
5873
5874<div class="doc_text">
5875
5876<h5>Syntax:</h5>
5877<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5878 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5879</pre>
5880
5881<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5882<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5883 of the function stack, for use
5884 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5885 useful for implementing language features like scoped automatic variable
5886 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5887
5888<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5889<p>This intrinsic returns a opaque pointer value that can be passed
5890 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5891 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5892 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5893 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5894 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5895 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5896
5897</div>
5898
5899<!-- _______________________________________________________________________ -->
5900<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5901 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5902</div>
5903
5904<div class="doc_text">
5905
5906<h5>Syntax:</h5>
5907<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5908 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5909</pre>
5910
5911<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5912<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5913 the function stack to the state it was in when the
5914 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5915 executed. This is useful for implementing language features like scoped
5916 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5917
5918<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5919<p>See the description
5920 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5921
5922</div>
5923
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5924<!-- _______________________________________________________________________ -->
5925<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5926 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5927</div>
5928
5929<div class="doc_text">
5930
5931<h5>Syntax:</h5>
5932<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5933 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5934</pre>
5935
5936<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5937<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5938 insert a prefetch instruction if supported; otherwise, it is a noop.
5939 Prefetches have no effect on the behavior of the program but can change its
5940 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5941
5942<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5943<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5944 specifier determining if the fetch should be for a read (0) or write (1),
5945 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5946 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5947 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5948
5949<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5950<p>This intrinsic does not modify the behavior of the program. In particular,
5951 prefetches cannot trap and do not produce a value. On targets that support
5952 this intrinsic, the prefetch can provide hints to the processor cache for
5953 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5954
5955</div>
5956
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5957<!-- _______________________________________________________________________ -->
5958<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5959 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5960</div>
5961
5962<div class="doc_text">
5963
5964<h5>Syntax:</h5>
5965<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5966 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5967</pre>
5968
5969<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5970<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5971 Counter (PC) in a region of code to simulators and other tools. The method
5972 is target specific, but it is expected that the marker will use exported
5973 symbols to transmit the PC of the marker. The marker makes no guarantees
5974 that it will remain with any specific instruction after optimizations. It is
5975 possible that the presence of a marker will inhibit optimizations. The
5976 intended use is to be inserted after optimizations to allow correlations of
5977 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5978
5979<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5980<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5981
5982<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5983<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5984 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5985
5986</div>
5987
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5988<!-- _______________________________________________________________________ -->
5989<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5990 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5991</div>
5992
5993<div class="doc_text">
5994
5995<h5>Syntax:</h5>
5996<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5997 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5998</pre>
5999
6000<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6001<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6002 counter register (or similar low latency, high accuracy clocks) on those
6003 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6004 should map to RPCC. As the backing counters overflow quickly (on the order
6005 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6006
6007<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6008<p>When directly supported, reading the cycle counter should not modify any
6009 memory. Implementations are allowed to either return a application specific
6010 value or a system wide value. On backends without support, this is lowered
6011 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6012
6013</div>
6014
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6015<!-- ======================================================================= -->
6016<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6017 <a name="int_libc">Standard C Library Intrinsics</a>
6018</div>
6019
6020<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6021
6022<p>LLVM provides intrinsics for a few important standard C library functions.
6023 These intrinsics allow source-language front-ends to pass information about
6024 the alignment of the pointer arguments to the code generator, providing
6025 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6026
6027</div>
6028
6029<!-- _______________________________________________________________________ -->
6030<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6031 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6032</div>
6033
6034<div class="doc_text">
6035
6036<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6037<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wange88909b2010-04-07 06:35:53 +0000[diff] [blame]6038 integer bit width and for different address spaces. Not all targets support
6039 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6040
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6041<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6042 declare void @llvm.memcpy.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6043 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6044 declare void @llvm.memcpy.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6045 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6046</pre>
6047
6048<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6049<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6050 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6051
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6052<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6053 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6054 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6055
6056<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6057
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6058<p>The first argument is a pointer to the destination, the second is a pointer
6059 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6060 number of bytes to copy, the fourth argument is the alignment of the
6061 source and destination locations, and the fifth is a boolean indicating a
6062 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6063
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6064<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6065 then the caller guarantees that both the source and destination pointers are
6066 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6067
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6068<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6069 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6070 The detailed access behavior is not very cleanly specified and it is unwise
6071 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6072
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6073<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6074
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6075<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6076 source location to the destination location, which are not allowed to
6077 overlap. It copies "len" bytes of memory over. If the argument is known to
6078 be aligned to some boundary, this can be specified as the fourth argument,
6079 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6080
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6081</div>
6082
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6083<!-- _______________________________________________________________________ -->
6084<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6085 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6086</div>
6087
6088<div class="doc_text">
6089
6090<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6091<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wange88909b2010-04-07 06:35:53 +0000[diff] [blame]6092 width and for different address space. Not all targets support all bit
6093 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6094
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6095<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6096 declare void @llvm.memmove.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6097 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6098 declare void @llvm.memmove.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6099 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6100</pre>
6101
6102<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6103<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6104 source location to the destination location. It is similar to the
6105 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6106 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6108<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6109 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6110 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6111
6112<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6113
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6114<p>The first argument is a pointer to the destination, the second is a pointer
6115 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6116 number of bytes to copy, the fourth argument is the alignment of the
6117 source and destination locations, and the fifth is a boolean indicating a
6118 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6119
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6120<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6121 then the caller guarantees that the source and destination pointers are
6122 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6123
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6124<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6125 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6126 The detailed access behavior is not very cleanly specified and it is unwise
6127 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6128
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6129<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6130
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6131<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6132 source location to the destination location, which may overlap. It copies
6133 "len" bytes of memory over. If the argument is known to be aligned to some
6134 boundary, this can be specified as the fourth argument, otherwise it should
6135 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6136
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6137</div>
6138
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6139<!-- _______________________________________________________________________ -->
6140<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6141 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6142</div>
6143
6144<div class="doc_text">
6145
6146<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6147<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Mon P Wange88909b2010-04-07 06:35:53 +0000[diff] [blame]6148 width and for different address spaces. Not all targets support all bit
6149 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6150
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6151<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6152 declare void @llvm.memset.p0i8.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6153 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6154 declare void @llvm.memset.p0i8.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6155 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6156</pre>
6157
6158<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6159<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6160 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6161
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6162<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6163 intrinsic does not return a value, takes extra alignment/volatile arguments,
6164 and the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6165
6166<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6167<p>The first argument is a pointer to the destination to fill, the second is the
6168 byte value to fill it with, the third argument is an integer argument
6169 specifying the number of bytes to fill, and the fourth argument is the known
6170 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6171
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6172<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6173 then the caller guarantees that the destination pointer is aligned to that
6174 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6175
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6176<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6177 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6178 The detailed access behavior is not very cleanly specified and it is unwise
6179 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6180
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6181<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6182<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6183 at the destination location. If the argument is known to be aligned to some
6184 boundary, this can be specified as the fourth argument, otherwise it should
6185 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6186
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6187</div>
6188
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6189<!-- _______________________________________________________________________ -->
6190<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6191 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6192</div>
6193
6194<div class="doc_text">
6195
6196<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6197<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6198 floating point or vector of floating point type. Not all targets support all
6199 types however.</p>
6200
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6201<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6202 declare float @llvm.sqrt.f32(float %Val)
6203 declare double @llvm.sqrt.f64(double %Val)
6204 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6205 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6206 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6207</pre>
6208
6209<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6210<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6211 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6212 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6213 behavior for negative numbers other than -0.0 (which allows for better
6214 optimization, because there is no need to worry about errno being
6215 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6216
6217<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6218<p>The argument and return value are floating point numbers of the same
6219 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6220
6221<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6222<p>This function returns the sqrt of the specified operand if it is a
6223 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6224
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6225</div>
6226
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6227<!-- _______________________________________________________________________ -->
6228<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6229 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6230</div>
6231
6232<div class="doc_text">
6233
6234<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6235<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6236 floating point or vector of floating point type. Not all targets support all
6237 types however.</p>
6238
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6239<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6240 declare float @llvm.powi.f32(float %Val, i32 %power)
6241 declare double @llvm.powi.f64(double %Val, i32 %power)
6242 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6243 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6244 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6245</pre>
6246
6247<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6248<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6249 specified (positive or negative) power. The order of evaluation of
6250 multiplications is not defined. When a vector of floating point type is
6251 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6252
6253<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6254<p>The second argument is an integer power, and the first is a value to raise to
6255 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6256
6257<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6258<p>This function returns the first value raised to the second power with an
6259 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6260
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6261</div>
6262
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6263<!-- _______________________________________________________________________ -->
6264<div class="doc_subsubsection">
6265 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6266</div>
6267
6268<div class="doc_text">
6269
6270<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6271<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6272 floating point or vector of floating point type. Not all targets support all
6273 types however.</p>
6274
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6275<pre>
6276 declare float @llvm.sin.f32(float %Val)
6277 declare double @llvm.sin.f64(double %Val)
6278 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6279 declare fp128 @llvm.sin.f128(fp128 %Val)
6280 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6281</pre>
6282
6283<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6284<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6285
6286<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6287<p>The argument and return value are floating point numbers of the same
6288 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6289
6290<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6291<p>This function returns the sine of the specified operand, returning the same
6292 values as the libm <tt>sin</tt> functions would, and handles error conditions
6293 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6294
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6295</div>
6296
6297<!-- _______________________________________________________________________ -->
6298<div class="doc_subsubsection">
6299 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6300</div>
6301
6302<div class="doc_text">
6303
6304<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6305<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6306 floating point or vector of floating point type. Not all targets support all
6307 types however.</p>
6308
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6309<pre>
6310 declare float @llvm.cos.f32(float %Val)
6311 declare double @llvm.cos.f64(double %Val)
6312 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6313 declare fp128 @llvm.cos.f128(fp128 %Val)
6314 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6315</pre>
6316
6317<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6318<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6319
6320<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6321<p>The argument and return value are floating point numbers of the same
6322 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6323
6324<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6325<p>This function returns the cosine of the specified operand, returning the same
6326 values as the libm <tt>cos</tt> functions would, and handles error conditions
6327 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6328
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6329</div>
6330
6331<!-- _______________________________________________________________________ -->
6332<div class="doc_subsubsection">
6333 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6334</div>
6335
6336<div class="doc_text">
6337
6338<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6339<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6340 floating point or vector of floating point type. Not all targets support all
6341 types however.</p>
6342
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6343<pre>
6344 declare float @llvm.pow.f32(float %Val, float %Power)
6345 declare double @llvm.pow.f64(double %Val, double %Power)
6346 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6347 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6348 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6349</pre>
6350
6351<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6352<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6353 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6354
6355<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6356<p>The second argument is a floating point power, and the first is a value to
6357 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6358
6359<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6360<p>This function returns the first value raised to the second power, returning
6361 the same values as the libm <tt>pow</tt> functions would, and handles error
6362 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6363
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6364</div>
6365
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6366<!-- ======================================================================= -->
6367<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6368 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6369</div>
6370
6371<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6372
6373<p>LLVM provides intrinsics for a few important bit manipulation operations.
6374 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6375
6376</div>
6377
6378<!-- _______________________________________________________________________ -->
6379<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6380 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6381</div>
6382
6383<div class="doc_text">
6384
6385<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6386<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6387 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6388
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6389<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6390 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6391 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6392 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6393</pre>
6394
6395<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6396<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6397 values with an even number of bytes (positive multiple of 16 bits). These
6398 are useful for performing operations on data that is not in the target's
6399 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6400
6401<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6402<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6403 and low byte of the input i16 swapped. Similarly,
6404 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6405 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6406 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6407 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6408 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6409 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6410
6411</div>
6412
6413<!-- _______________________________________________________________________ -->
6414<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6415 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6416</div>
6417
6418<div class="doc_text">
6419
6420<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6421<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6422 width. Not all targets support all bit widths however.</p>
6423
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6424<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6425 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6426 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6427 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6428 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6429 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6430</pre>
6431
6432<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6433<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6434 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6435
6436<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6437<p>The only argument is the value to be counted. The argument may be of any
6438 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6439
6440<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6441<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6442
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6443</div>
6444
6445<!-- _______________________________________________________________________ -->
6446<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6447 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6448</div>
6449
6450<div class="doc_text">
6451
6452<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6453<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6454 integer bit width. Not all targets support all bit widths however.</p>
6455
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6456<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6457 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6458 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6459 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6460 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6461 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6462</pre>
6463
6464<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6465<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6466 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6467
6468<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6469<p>The only argument is the value to be counted. The argument may be of any
6470 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6471
6472<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6473<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6474 zeros in a variable. If the src == 0 then the result is the size in bits of
6475 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6476
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6477</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6478
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6479<!-- _______________________________________________________________________ -->
6480<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6481 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6482</div>
6483
6484<div class="doc_text">
6485
6486<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6487<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6488 integer bit width. Not all targets support all bit widths however.</p>
6489
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6490<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6491 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6492 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6493 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6494 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6495 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6496</pre>
6497
6498<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6499<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6500 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6501
6502<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6503<p>The only argument is the value to be counted. The argument may be of any
6504 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6505
6506<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6507<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6508 zeros in a variable. If the src == 0 then the result is the size in bits of
6509 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6510
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6511</div>
6512
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6513<!-- ======================================================================= -->
6514<div class="doc_subsection">
6515 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6516</div>
6517
6518<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6519
6520<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6521
6522</div>
6523
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6524<!-- _______________________________________________________________________ -->
6525<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6526 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6527</div>
6528
6529<div class="doc_text">
6530
6531<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6532<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6533 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6534
6535<pre>
6536 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6537 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6538 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6539</pre>
6540
6541<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6542<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6543 a signed addition of the two arguments, and indicate whether an overflow
6544 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6545
6546<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6547<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6548 be of integer types of any bit width, but they must have the same bit
6549 width. The second element of the result structure must be of
6550 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6551 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6552
6553<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6554<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6555 a signed addition of the two variables. They return a structure &mdash; the
6556 first element of which is the signed summation, and the second element of
6557 which is a bit specifying if the signed summation resulted in an
6558 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6559
6560<h5>Examples:</h5>
6561<pre>
6562 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6563 %sum = extractvalue {i32, i1} %res, 0
6564 %obit = extractvalue {i32, i1} %res, 1
6565 br i1 %obit, label %overflow, label %normal
6566</pre>
6567
6568</div>
6569
6570<!-- _______________________________________________________________________ -->
6571<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6572 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6573</div>
6574
6575<div class="doc_text">
6576
6577<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6578<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6579 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6580
6581<pre>
6582 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6583 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6584 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6585</pre>
6586
6587<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6588<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6589 an unsigned addition of the two arguments, and indicate whether a carry
6590 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6591
6592<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6593<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6594 be of integer types of any bit width, but they must have the same bit
6595 width. The second element of the result structure must be of
6596 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6597 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6598
6599<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6600<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6601 an unsigned addition of the two arguments. They return a structure &mdash;
6602 the first element of which is the sum, and the second element of which is a
6603 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6604
6605<h5>Examples:</h5>
6606<pre>
6607 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6608 %sum = extractvalue {i32, i1} %res, 0
6609 %obit = extractvalue {i32, i1} %res, 1
6610 br i1 %obit, label %carry, label %normal
6611</pre>
6612
6613</div>
6614
6615<!-- _______________________________________________________________________ -->
6616<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6617 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6618</div>
6619
6620<div class="doc_text">
6621
6622<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6623<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6624 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6625
6626<pre>
6627 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6628 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6629 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6630</pre>
6631
6632<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6633<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6634 a signed subtraction of the two arguments, and indicate whether an overflow
6635 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6636
6637<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6638<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6639 be of integer types of any bit width, but they must have the same bit
6640 width. The second element of the result structure must be of
6641 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6642 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6643
6644<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6645<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6646 a signed subtraction of the two arguments. They return a structure &mdash;
6647 the first element of which is the subtraction, and the second element of
6648 which is a bit specifying if the signed subtraction resulted in an
6649 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6650
6651<h5>Examples:</h5>
6652<pre>
6653 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6654 %sum = extractvalue {i32, i1} %res, 0
6655 %obit = extractvalue {i32, i1} %res, 1
6656 br i1 %obit, label %overflow, label %normal
6657</pre>
6658
6659</div>
6660
6661<!-- _______________________________________________________________________ -->
6662<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6663 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6664</div>
6665
6666<div class="doc_text">
6667
6668<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6669<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6670 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6671
6672<pre>
6673 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6674 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6675 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6676</pre>
6677
6678<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6679<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6680 an unsigned subtraction of the two arguments, and indicate whether an
6681 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6682
6683<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6684<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6685 be of integer types of any bit width, but they must have the same bit
6686 width. The second element of the result structure must be of
6687 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6688 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6689
6690<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6691<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6692 an unsigned subtraction of the two arguments. They return a structure &mdash;
6693 the first element of which is the subtraction, and the second element of
6694 which is a bit specifying if the unsigned subtraction resulted in an
6695 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6696
6697<h5>Examples:</h5>
6698<pre>
6699 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6700 %sum = extractvalue {i32, i1} %res, 0
6701 %obit = extractvalue {i32, i1} %res, 1
6702 br i1 %obit, label %overflow, label %normal
6703</pre>
6704
6705</div>
6706
6707<!-- _______________________________________________________________________ -->
6708<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6709 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6710</div>
6711
6712<div class="doc_text">
6713
6714<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6715<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6716 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6717
6718<pre>
6719 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6720 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6721 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6722</pre>
6723
6724<h5>Overview:</h5>
6725
6726<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6727 a signed multiplication of the two arguments, and indicate whether an
6728 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6729
6730<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6731<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6732 be of integer types of any bit width, but they must have the same bit
6733 width. The second element of the result structure must be of
6734 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6735 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6736
6737<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6738<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6739 a signed multiplication of the two arguments. They return a structure &mdash;
6740 the first element of which is the multiplication, and the second element of
6741 which is a bit specifying if the signed multiplication resulted in an
6742 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6743
6744<h5>Examples:</h5>
6745<pre>
6746 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6747 %sum = extractvalue {i32, i1} %res, 0
6748 %obit = extractvalue {i32, i1} %res, 1
6749 br i1 %obit, label %overflow, label %normal
6750</pre>
6751
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6752</div>
6753
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6754<!-- _______________________________________________________________________ -->
6755<div class="doc_subsubsection">
6756 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6757</div>
6758
6759<div class="doc_text">
6760
6761<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6762<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6763 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6764
6765<pre>
6766 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6767 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6768 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6769</pre>
6770
6771<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6772<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6773 a unsigned multiplication of the two arguments, and indicate whether an
6774 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6775
6776<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6777<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6778 be of integer types of any bit width, but they must have the same bit
6779 width. The second element of the result structure must be of
6780 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6781 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6782
6783<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6784<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6785 an unsigned multiplication of the two arguments. They return a structure
6786 &mdash; the first element of which is the multiplication, and the second
6787 element of which is a bit specifying if the unsigned multiplication resulted
6788 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6789
6790<h5>Examples:</h5>
6791<pre>
6792 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6793 %sum = extractvalue {i32, i1} %res, 0
6794 %obit = extractvalue {i32, i1} %res, 1
6795 br i1 %obit, label %overflow, label %normal
6796</pre>
6797
6798</div>
6799
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6800<!-- ======================================================================= -->
6801<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6802 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6803</div>
6804
6805<div class="doc_text">
6806
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6807<p>Half precision floating point is a storage-only format. This means that it is
6808 a dense encoding (in memory) but does not support computation in the
6809 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6810
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6811<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6812 value as an i16, then convert it to float with <a
6813 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6814 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6815 double etc). To store the value back to memory, it is first converted to
6816 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6817 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6818 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6819</div>
6820
6821<!-- _______________________________________________________________________ -->
6822<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6823 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6824</div>
6825
6826<div class="doc_text">
6827
6828<h5>Syntax:</h5>
6829<pre>
6830 declare i16 @llvm.convert.to.fp16(f32 %a)
6831</pre>
6832
6833<h5>Overview:</h5>
6834<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6835 a conversion from single precision floating point format to half precision
6836 floating point format.</p>
6837
6838<h5>Arguments:</h5>
6839<p>The intrinsic function contains single argument - the value to be
6840 converted.</p>
6841
6842<h5>Semantics:</h5>
6843<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6844 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6845 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6846 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6847
6848<h5>Examples:</h5>
6849<pre>
6850 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6851 store i16 %res, i16* @x, align 2
6852</pre>
6853
6854</div>
6855
6856<!-- _______________________________________________________________________ -->
6857<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6858 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6859</div>
6860
6861<div class="doc_text">
6862
6863<h5>Syntax:</h5>
6864<pre>
6865 declare f32 @llvm.convert.from.fp16(i16 %a)
6866</pre>
6867
6868<h5>Overview:</h5>
6869<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6870 a conversion from half precision floating point format to single precision
6871 floating point format.</p>
6872
6873<h5>Arguments:</h5>
6874<p>The intrinsic function contains single argument - the value to be
6875 converted.</p>
6876
6877<h5>Semantics:</h5>
6878<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6879 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6880 precision floating point format. The input half-float value is represented by
6881 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6882
6883<h5>Examples:</h5>
6884<pre>
6885 %a = load i16* @x, align 2
6886 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6887</pre>
6888
6889</div>
6890
6891<!-- ======================================================================= -->
6892<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6893 <a name="int_debugger">Debugger Intrinsics</a>
6894</div>
6895
6896<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6897
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6898<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6899 prefix), are described in
6900 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6901 Level Debugging</a> document.</p>
6902
6903</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6904
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6905<!-- ======================================================================= -->
6906<div class="doc_subsection">
6907 <a name="int_eh">Exception Handling Intrinsics</a>
6908</div>
6909
6910<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6911
6912<p>The LLVM exception handling intrinsics (which all start with
6913 <tt>llvm.eh.</tt> prefix), are described in
6914 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6915 Handling</a> document.</p>
6916
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6917</div>
6918
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6919<!-- ======================================================================= -->
6920<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6921 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6922</div>
6923
6924<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6925
6926<p>This intrinsic makes it possible to excise one parameter, marked with
6927 the <tt>nest</tt> attribute, from a function. The result is a callable
6928 function pointer lacking the nest parameter - the caller does not need to
6929 provide a value for it. Instead, the value to use is stored in advance in a
6930 "trampoline", a block of memory usually allocated on the stack, which also
6931 contains code to splice the nest value into the argument list. This is used
6932 to implement the GCC nested function address extension.</p>
6933
6934<p>For example, if the function is
6935 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6936 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6937 follows:</p>
6938
6939<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6940<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6941 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6942 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6943 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6944 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6945</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6946</div>
6947
6948<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6949 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6950
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6951</div>
6952
6953<!-- _______________________________________________________________________ -->
6954<div class="doc_subsubsection">
6955 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6956</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6957
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6958<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6959
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6960<h5>Syntax:</h5>
6961<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6962 declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6963</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6964
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6965<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6966<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6967 function pointer suitable for executing it.</p>
6968
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6969<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6970<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6971 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6972 sufficiently aligned block of memory; this memory is written to by the
6973 intrinsic. Note that the size and the alignment are target-specific - LLVM
6974 currently provides no portable way of determining them, so a front-end that
6975 generates this intrinsic needs to have some target-specific knowledge.
6976 The <tt>func</tt> argument must hold a function bitcast to
6977 an <tt>i8*</tt>.</p>
6978
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6979<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6980<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6981 dependent code, turning it into a function. A pointer to this function is
6982 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6983 function pointer type</a> before being called. The new function's signature
6984 is the same as that of <tt>func</tt> with any arguments marked with
6985 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6986 is allowed, and it must be of pointer type. Calling the new function is
6987 equivalent to calling <tt>func</tt> with the same argument list, but
6988 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6989 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6990 by <tt>tramp</tt> is modified, then the effect of any later call to the
6991 returned function pointer is undefined.</p>
6992
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6993</div>
6994
6995<!-- ======================================================================= -->
6996<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6997 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6998</div>
6999
7000<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7001
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7002<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7003 hardware constructs for atomic operations and memory synchronization. This
7004 provides an interface to the hardware, not an interface to the programmer. It
7005 is aimed at a low enough level to allow any programming models or APIs
7006 (Application Programming Interfaces) which need atomic behaviors to map
7007 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7008 hardware provides a "universal IR" for source languages, it also provides a
7009 starting point for developing a "universal" atomic operation and
7010 synchronization IR.</p>
7011
7012<p>These do <em>not</em> form an API such as high-level threading libraries,
7013 software transaction memory systems, atomic primitives, and intrinsic
7014 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7015 application libraries. The hardware interface provided by LLVM should allow
7016 a clean implementation of all of these APIs and parallel programming models.
7017 No one model or paradigm should be selected above others unless the hardware
7018 itself ubiquitously does so.</p>
7019
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7020</div>
7021
7022<!-- _______________________________________________________________________ -->
7023<div class="doc_subsubsection">
7024 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7025</div>
7026<div class="doc_text">
7027<h5>Syntax:</h5>
7028<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7029 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 Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7030</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7031
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7032<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7033<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7034 specific pairs of memory access types.</p>
7035
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7036<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7037<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7038 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7039 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7040 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7041
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7042<ul>
7043 <li><tt>ll</tt>: load-load barrier</li>
7044 <li><tt>ls</tt>: load-store barrier</li>
7045 <li><tt>sl</tt>: store-load barrier</li>
7046 <li><tt>ss</tt>: store-store barrier</li>
7047 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7048</ul>
7049
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7050<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7051<p>This intrinsic causes the system to enforce some ordering constraints upon
7052 the loads and stores of the program. This barrier does not
7053 indicate <em>when</em> any events will occur, it only enforces
7054 an <em>order</em> in which they occur. For any of the specified pairs of load
7055 and store operations (f.ex. load-load, or store-load), all of the first
7056 operations preceding the barrier will complete before any of the second
7057 operations succeeding the barrier begin. Specifically the semantics for each
7058 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7059
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7060<ul>
7061 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7062 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7063 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7064 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7065 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7066 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7067 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7068 load after the barrier begins.</li>
7069</ul>
7070
7071<p>These semantics are applied with a logical "and" behavior when more than one
7072 is enabled in a single memory barrier intrinsic.</p>
7073
7074<p>Backends may implement stronger barriers than those requested when they do
7075 not support as fine grained a barrier as requested. Some architectures do
7076 not need all types of barriers and on such architectures, these become
7077 noops.</p>
7078
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7079<h5>Example:</h5>
7080<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7081%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7082%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7083 store i32 4, %ptr
7084
7085%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
7086 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
7087 <i>; guarantee the above finishes</i>
7088 store i32 8, %ptr <i>; before this begins</i>
7089</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7090
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7091</div>
7092
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7093<!-- _______________________________________________________________________ -->
7094<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7095 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7096</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7097
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7098<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7099
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7100<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7101<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7102 any integer bit width and for different address spaces. Not all targets
7103 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7104
7105<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7106 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
7107 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
7108 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
7109 declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7110</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7111
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7112<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7113<p>This loads a value in memory and compares it to a given value. If they are
7114 equal, it stores a new value into the memory.</p>
7115
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7116<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7117<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7118 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7119 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7120 this integer type. While any bit width integer may be used, targets may only
7121 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7122
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7123<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7124<p>This entire intrinsic must be executed atomically. It first loads the value
7125 in memory pointed to by <tt>ptr</tt> and compares it with the
7126 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7127 memory. The loaded value is yielded in all cases. This provides the
7128 equivalent of an atomic compare-and-swap operation within the SSA
7129 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7130
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7131<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7132<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7133%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7134%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7135 store i32 4, %ptr
7136
7137%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7138%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7139 <i>; yields {i32}:result1 = 4</i>
7140%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7141%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7142
7143%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7144%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7145 <i>; yields {i32}:result2 = 8</i>
7146%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7147
7148%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7149</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7150
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7151</div>
7152
7153<!-- _______________________________________________________________________ -->
7154<div class="doc_subsubsection">
7155 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7156</div>
7157<div class="doc_text">
7158<h5>Syntax:</h5>
7159
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7160<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7161 integer bit width. Not all targets support all bit widths however.</p>
7162
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7163<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7164 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
7165 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
7166 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
7167 declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7168</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7169
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7170<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7171<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7172 the value from memory. It then stores the value in <tt>val</tt> in the memory
7173 at <tt>ptr</tt>.</p>
7174
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7175<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7176<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7177 the <tt>val</tt> argument and the result must be integers of the same bit
7178 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7179 integer type. The targets may only lower integer representations they
7180 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7181
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7182<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7183<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7184 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7185 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7186
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7187<h5>Examples:</h5>
7188<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7189%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7190%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7191 store i32 4, %ptr
7192
7193%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7194%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7195 <i>; yields {i32}:result1 = 4</i>
7196%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7197%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7198
7199%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7200%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7201 <i>; yields {i32}:result2 = 8</i>
7202
7203%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7204%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7205</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7206
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7207</div>
7208
7209<!-- _______________________________________________________________________ -->
7210<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7211 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7212
7213</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7214
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7215<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7216
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7217<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7218<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7219 any integer bit width. Not all targets support all bit widths however.</p>
7220
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7221<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7222 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7223 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7224 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7225 declare i64 @llvm.atomic.load.add.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7226</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7227
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7228<h5>Overview:</h5>
7229<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7230 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7231
7232<h5>Arguments:</h5>
7233<p>The intrinsic takes two arguments, the first a pointer to an integer value
7234 and the second an integer value. The result is also an integer value. These
7235 integer types can have any bit width, but they must all have the same bit
7236 width. The targets may only lower integer representations they support.</p>
7237
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7238<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7239<p>This intrinsic does a series of operations atomically. It first loads the
7240 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7241 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7242
7243<h5>Examples:</h5>
7244<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7245%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7246%ptr = bitcast i8* %mallocP to i32*
7247 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7248%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7249 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7250%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7251 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7252%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7253 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7254%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7255</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7256
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7257</div>
7258
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7259<!-- _______________________________________________________________________ -->
7260<div class="doc_subsubsection">
7261 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7262
7263</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7264
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7265<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7266
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7267<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7268<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7269 any integer bit width and for different address spaces. Not all targets
7270 support all bit widths however.</p>
7271
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7272<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7273 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7274 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7275 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7276 declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7277</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7278
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7279<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7280<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7281 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7282
7283<h5>Arguments:</h5>
7284<p>The intrinsic takes two arguments, the first a pointer to an integer value
7285 and the second an integer value. The result is also an integer value. These
7286 integer types can have any bit width, but they must all have the same bit
7287 width. The targets may only lower integer representations they support.</p>
7288
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7289<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7290<p>This intrinsic does a series of operations atomically. It first loads the
7291 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7292 result to <tt>ptr</tt>. It yields the original value stored
7293 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7294
7295<h5>Examples:</h5>
7296<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7297%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7298%ptr = bitcast i8* %mallocP to i32*
7299 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7300%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7301 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7302%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7303 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7304%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7305 <i>; yields {i32}:result3 = 2</i>
7306%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7307</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7308
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7309</div>
7310
7311<!-- _______________________________________________________________________ -->
7312<div class="doc_subsubsection">
7313 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7314 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7315 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7316 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7317</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7318
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7319<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7320
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7321<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7322<p>These are overloaded intrinsics. You can
7323 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7324 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7325 bit width and for different address spaces. Not all targets support all bit
7326 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7327
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7328<pre>
7329 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7330 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7331 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7332 declare i64 @llvm.atomic.load.and.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7333</pre>
7334
7335<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7336 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7337 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7338 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7339 declare i64 @llvm.atomic.load.or.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7340</pre>
7341
7342<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7343 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7344 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7345 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7346 declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7347</pre>
7348
7349<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7350 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7351 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7352 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7353 declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7354</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7355
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7356<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7357<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7358 the value stored in memory at <tt>ptr</tt>. It yields the original value
7359 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7360
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7361<h5>Arguments:</h5>
7362<p>These intrinsics take two arguments, the first a pointer to an integer value
7363 and the second an integer value. The result is also an integer value. These
7364 integer types can have any bit width, but they must all have the same bit
7365 width. The targets may only lower integer representations they support.</p>
7366
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7367<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7368<p>These intrinsics does a series of operations atomically. They first load the
7369 value stored at <tt>ptr</tt>. They then do the bitwise
7370 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7371 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7372
7373<h5>Examples:</h5>
7374<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7375%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7376%ptr = bitcast i8* %mallocP to i32*
7377 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7378%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7379 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7380%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7381 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7382%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7383 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7384%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7385 <i>; yields {i32}:result3 = FF</i>
7386%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7387</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7388
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7389</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7390
7391<!-- _______________________________________________________________________ -->
7392<div class="doc_subsubsection">
7393 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7394 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7395 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7396 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7397</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7398
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7399<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7400
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7401<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7402<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7403 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7404 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7405 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7406
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7407<pre>
7408 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7409 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7410 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7411 declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7412</pre>
7413
7414<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7415 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7416 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7417 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7418 declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7419</pre>
7420
7421<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7422 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7423 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7424 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7425 declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7426</pre>
7427
7428<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7429 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7430 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7431 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7432 declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7433</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7434
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7435<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7436<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7437 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7438 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7439
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7440<h5>Arguments:</h5>
7441<p>These intrinsics take two arguments, the first a pointer to an integer value
7442 and the second an integer value. The result is also an integer value. These
7443 integer types can have any bit width, but they must all have the same bit
7444 width. The targets may only lower integer representations they support.</p>
7445
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7446<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7447<p>These intrinsics does a series of operations atomically. They first load the
7448 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7449 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7450 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7451
7452<h5>Examples:</h5>
7453<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7454%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7455%ptr = bitcast i8* %mallocP to i32*
7456 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7457%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7458 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7459%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7460 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7461%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7462 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7463%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7464 <i>; yields {i32}:result3 = 8</i>
7465%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7466</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7467
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7468</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7469
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7470
7471<!-- ======================================================================= -->
7472<div class="doc_subsection">
7473 <a name="int_memorymarkers">Memory Use Markers</a>
7474</div>
7475
7476<div class="doc_text">
7477
7478<p>This class of intrinsics exists to information about the lifetime of memory
7479 objects and ranges where variables are immutable.</p>
7480
7481</div>
7482
7483<!-- _______________________________________________________________________ -->
7484<div class="doc_subsubsection">
7485 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7486</div>
7487
7488<div class="doc_text">
7489
7490<h5>Syntax:</h5>
7491<pre>
7492 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7493</pre>
7494
7495<h5>Overview:</h5>
7496<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7497 object's lifetime.</p>
7498
7499<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7500<p>The first argument is a constant integer representing the size of the
7501 object, or -1 if it is variable sized. The second argument is a pointer to
7502 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7503
7504<h5>Semantics:</h5>
7505<p>This intrinsic indicates that before this point in the code, the value of the
7506 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewycky8d336592009-10-27 16:56:58 +0000[diff] [blame]7507 never be used and has an undefined value. A load from the pointer that
7508 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7509 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7510
7511</div>
7512
7513<!-- _______________________________________________________________________ -->
7514<div class="doc_subsubsection">
7515 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7516</div>
7517
7518<div class="doc_text">
7519
7520<h5>Syntax:</h5>
7521<pre>
7522 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7523</pre>
7524
7525<h5>Overview:</h5>
7526<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7527 object's lifetime.</p>
7528
7529<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7530<p>The first argument is a constant integer representing the size of the
7531 object, or -1 if it is variable sized. The second argument is a pointer to
7532 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7533
7534<h5>Semantics:</h5>
7535<p>This intrinsic indicates that after this point in the code, the value of the
7536 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7537 never be used and has an undefined value. Any stores into the memory object
7538 following this intrinsic may be removed as dead.
7539
7540</div>
7541
7542<!-- _______________________________________________________________________ -->
7543<div class="doc_subsubsection">
7544 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7545</div>
7546
7547<div class="doc_text">
7548
7549<h5>Syntax:</h5>
7550<pre>
7551 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7552</pre>
7553
7554<h5>Overview:</h5>
7555<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7556 a memory object will not change.</p>
7557
7558<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7559<p>The first argument is a constant integer representing the size of the
7560 object, or -1 if it is variable sized. The second argument is a pointer to
7561 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7562
7563<h5>Semantics:</h5>
7564<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7565 the return value, the referenced memory location is constant and
7566 unchanging.</p>
7567
7568</div>
7569
7570<!-- _______________________________________________________________________ -->
7571<div class="doc_subsubsection">
7572 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7573</div>
7574
7575<div class="doc_text">
7576
7577<h5>Syntax:</h5>
7578<pre>
7579 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7580</pre>
7581
7582<h5>Overview:</h5>
7583<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7584 a memory object are mutable.</p>
7585
7586<h5>Arguments:</h5>
7587<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7588 The second argument is a constant integer representing the size of the
7589 object, or -1 if it is variable sized and the third argument is a pointer
7590 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7591
7592<h5>Semantics:</h5>
7593<p>This intrinsic indicates that the memory is mutable again.</p>
7594
7595</div>
7596
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7597<!-- ======================================================================= -->
7598<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7599 <a name="int_general">General Intrinsics</a>
7600</div>
7601
7602<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7603
7604<p>This class of intrinsics is designed to be generic and has no specific
7605 purpose.</p>
7606
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7607</div>
7608
7609<!-- _______________________________________________________________________ -->
7610<div class="doc_subsubsection">
7611 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7612</div>
7613
7614<div class="doc_text">
7615
7616<h5>Syntax:</h5>
7617<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7618 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7619</pre>
7620
7621<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7622<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7623
7624<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7625<p>The first argument is a pointer to a value, the second is a pointer to a
7626 global string, the third is a pointer to a global string which is the source
7627 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7628
7629<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7630<p>This intrinsic allows annotation of local variables with arbitrary strings.
7631 This can be useful for special purpose optimizations that want to look for
7632 these annotations. These have no other defined use, they are ignored by code
7633 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7634
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7635</div>
7636
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7637<!-- _______________________________________________________________________ -->
7638<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7639 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7640</div>
7641
7642<div class="doc_text">
7643
7644<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7645<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7646 any integer bit width.</p>
7647
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7648<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7649 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7650 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7651 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7652 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7653 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7654</pre>
7655
7656<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7657<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7658
7659<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7660<p>The first argument is an integer value (result of some expression), the
7661 second is a pointer to a global string, the third is a pointer to a global
7662 string which is the source file name, and the last argument is the line
7663 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7664
7665<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7666<p>This intrinsic allows annotations to be put on arbitrary expressions with
7667 arbitrary strings. This can be useful for special purpose optimizations that
7668 want to look for these annotations. These have no other defined use, they
7669 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7670
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7671</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7672
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7673<!-- _______________________________________________________________________ -->
7674<div class="doc_subsubsection">
7675 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7676</div>
7677
7678<div class="doc_text">
7679
7680<h5>Syntax:</h5>
7681<pre>
7682 declare void @llvm.trap()
7683</pre>
7684
7685<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7686<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7687
7688<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7689<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7690
7691<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7692<p>This intrinsics is lowered to the target dependent trap instruction. If the
7693 target does not have a trap instruction, this intrinsic will be lowered to
7694 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7695
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7696</div>
7697
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7698<!-- _______________________________________________________________________ -->
7699<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7700 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7701</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7702
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7703<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7704
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7705<h5>Syntax:</h5>
7706<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7707 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7708</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7709
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7710<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7711<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7712 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7713 ensure that it is placed on the stack before local variables.</p>
7714
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7715<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7716<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7717 arguments. The first argument is the value loaded from the stack
7718 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7719 that has enough space to hold the value of the guard.</p>
7720
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7721<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7722<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7723 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7724 stack. This is to ensure that if a local variable on the stack is
7725 overwritten, it will destroy the value of the guard. When the function exits,
7726 the guard on the stack is checked against the original guard. If they're
7727 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7728 function.</p>
7729
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7730</div>
7731
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7732<!-- _______________________________________________________________________ -->
7733<div class="doc_subsubsection">
7734 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7735</div>
7736
7737<div class="doc_text">
7738
7739<h5>Syntax:</h5>
7740<pre>
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7741 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7742 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7743</pre>
7744
7745<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7746<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7747 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7748 operation like memcpy will either overflow a buffer that corresponds to
7749 an object, or b) to determine that a runtime check for overflow isn't
7750 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7751 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7752
7753<h5>Arguments:</h5>
7754<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7755 argument is a pointer to or into the <tt>object</tt>. The second argument
7756 is a boolean 0 or 1. This argument determines whether you want the
7757 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7758 1, variables are not allowed.</p>
7759
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7760<h5>Semantics:</h5>
7761<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7762 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7763 (depending on the <tt>type</tt> argument if the size cannot be determined
7764 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7765
7766</div>
7767
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7768<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7769<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7770<address>
7771 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7772 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7773 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7774 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7775
7776 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7777 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7778 Last modified: $Date$
7779</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7780
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7781</body>
7782</html>