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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / ae11c3f83e92d776b9f24a569532229ba106b4b0 / . / 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 Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]854<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]855 the alignment is set to zero, the alignment of the global is set by the
856 target to whatever it feels convenient. If an explicit alignment is
857 specified, the global is forced to have at least that much alignment. All
858 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]859
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]860<p>For example, the following defines a global in a numbered address space with
861 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]862
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]863<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]864<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]865@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]866</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]867</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]868
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]869</div>
870
871
872<!-- ======================================================================= -->
873<div class="doc_subsection">
874 <a name="functionstructure">Functions</a>
875</div>
876
877<div class="doc_text">
878
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]879<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]880 optional <a href="#linkage">linkage type</a>, an optional
881 <a href="#visibility">visibility style</a>, an optional
882 <a href="#callingconv">calling convention</a>, a return type, an optional
883 <a href="#paramattrs">parameter attribute</a> for the return type, a function
884 name, a (possibly empty) argument list (each with optional
885 <a href="#paramattrs">parameter attributes</a>), optional
886 <a href="#fnattrs">function attributes</a>, an optional section, an optional
887 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
888 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]889
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]890<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
891 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]892 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]893 <a href="#callingconv">calling convention</a>, a return type, an optional
894 <a href="#paramattrs">parameter attribute</a> for the return type, a function
895 name, a possibly empty list of arguments, an optional alignment, and an
896 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]897
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]898<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899 (Control Flow Graph) for the function. Each basic block may optionally start
900 with a label (giving the basic block a symbol table entry), contains a list
901 of instructions, and ends with a <a href="#terminators">terminator</a>
902 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]903
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]904<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]905 executed on entrance to the function, and it is not allowed to have
906 predecessor basic blocks (i.e. there can not be any branches to the entry
907 block of a function). Because the block can have no predecessors, it also
908 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]909
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]910<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]911 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]912
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]913<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]914 the alignment is set to zero, the alignment of the function is set by the
915 target to whatever it feels convenient. If an explicit alignment is
916 specified, the function is forced to have at least that much alignment. All
917 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]918
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]919<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]920<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]921<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]922define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]923 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
924 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
925 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
926 [<a href="#gc">gc</a>] { ... }
927</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]928</div>
929
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]930</div>
931
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]932<!-- ======================================================================= -->
933<div class="doc_subsection">
934 <a name="aliasstructure">Aliases</a>
935</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]936
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]937<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]938
939<p>Aliases act as "second name" for the aliasee value (which can be either
940 function, global variable, another alias or bitcast of global value). Aliases
941 may have an optional <a href="#linkage">linkage type</a>, and an
942 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]943
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]944<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]945<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]946<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]947@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]948</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]949</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]950
951</div>
952
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]953<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]954<div class="doc_subsection">
955 <a name="namedmetadatastructure">Named Metadata</a>
956</div>
957
958<div class="doc_text">
959
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]960<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
961 nodes</a> (but not metadata strings) and null are the only valid operands for
962 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]963
964<h5>Syntax:</h5>
965<div class="doc_code">
966<pre>
967!1 = metadata !{metadata !"one"}
968!name = !{null, !1}
969</pre>
970</div>
971
972</div>
973
974<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]975<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]976
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]977<div class="doc_text">
978
979<p>The return type and each parameter of a function type may have a set of
980 <i>parameter attributes</i> associated with them. Parameter attributes are
981 used to communicate additional information about the result or parameters of
982 a function. Parameter attributes are considered to be part of the function,
983 not of the function type, so functions with different parameter attributes
984 can have the same function type.</p>
985
986<p>Parameter attributes are simple keywords that follow the type specified. If
987 multiple parameter attributes are needed, they are space separated. For
988 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]989
990<div class="doc_code">
991<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]992declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]993declare i32 @atoi(i8 zeroext)
994declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]995</pre>
996</div>
997
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]998<p>Note that any attributes for the function result (<tt>nounwind</tt>,
999 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1000
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1001<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1002
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1003<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1004 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005 <dd>This indicates to the code generator that the parameter or return value
1006 should be zero-extended to a 32-bit value by the caller (for a parameter)
1007 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1008
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1009 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1010 <dd>This indicates to the code generator that the parameter or return value
1011 should be sign-extended to a 32-bit value by the caller (for a parameter)
1012 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1013
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1014 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1015 <dd>This indicates that this parameter or return value should be treated in a
1016 special target-dependent fashion during while emitting code for a function
1017 call or return (usually, by putting it in a register as opposed to memory,
1018 though some targets use it to distinguish between two different kinds of
1019 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1020
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1021 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1022 <dd>This indicates that the pointer parameter should really be passed by value
1023 to the function. The attribute implies that a hidden copy of the pointee
1024 is made between the caller and the callee, so the callee is unable to
1025 modify the value in the callee. This attribute is only valid on LLVM
1026 pointer arguments. It is generally used to pass structs and arrays by
1027 value, but is also valid on pointers to scalars. The copy is considered
1028 to belong to the caller not the callee (for example,
1029 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1030 <tt>byval</tt> parameters). This is not a valid attribute for return
1031 values. The byval attribute also supports specifying an alignment with
1032 the align attribute. This has a target-specific effect on the code
1033 generator that usually indicates a desired alignment for the synthesized
1034 stack slot.</dd>
1035
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1036 <dt><tt><b>sret</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1037 <dd>This indicates that the pointer parameter specifies the address of a
1038 structure that is the return value of the function in the source program.
1039 This pointer must be guaranteed by the caller to be valid: loads and
1040 stores to the structure may be assumed by the callee to not to trap. This
1041 may only be applied to the first parameter. This is not a valid attribute
1042 for return values. </dd>
1043
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1044 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1045 <dd>This indicates that the pointer does not alias any global or any other
1046 parameter. The caller is responsible for ensuring that this is the
1047 case. On a function return value, <tt>noalias</tt> additionally indicates
1048 that the pointer does not alias any other pointers visible to the
1049 caller. For further details, please see the discussion of the NoAlias
1050 response in
1051 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1052 analysis</a>.</dd>
1053
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1054 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1055 <dd>This indicates that the callee does not make any copies of the pointer
1056 that outlive the callee itself. This is not a valid attribute for return
1057 values.</dd>
1058
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1059 <dt><tt><b>nest</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1060 <dd>This indicates that the pointer parameter can be excised using the
1061 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1062 attribute for return values.</dd>
1063</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1064
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1065</div>
1066
1067<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1068<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1069 <a name="gc">Garbage Collector Names</a>
1070</div>
1071
1072<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1073
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1074<p>Each function may specify a garbage collector name, which is simply a
1075 string:</p>
1076
1077<div class="doc_code">
1078<pre>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1079define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1080</pre>
1081</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1082
1083<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1084 collector which will cause the compiler to alter its output in order to
1085 support the named garbage collection algorithm.</p>
1086
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1087</div>
1088
1089<!-- ======================================================================= -->
1090<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1091 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1092</div>
1093
1094<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1095
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1096<p>Function attributes are set to communicate additional information about a
1097 function. Function attributes are considered to be part of the function, not
1098 of the function type, so functions with different parameter attributes can
1099 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1100
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1101<p>Function attributes are simple keywords that follow the type specified. If
1102 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1103
1104<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1105<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1106define void @f() noinline { ... }
1107define void @f() alwaysinline { ... }
1108define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1109define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1110</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1111</div>
1112
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1113<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1114 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1115 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1116 the backend should forcibly align the stack pointer. Specify the
1117 desired alignment, which must be a power of two, in parentheses.
1118
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1119 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1120 <dd>This attribute indicates that the inliner should attempt to inline this
1121 function into callers whenever possible, ignoring any active inlining size
1122 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1123
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1124 <dt><tt><b>inlinehint</b></tt></dt>
1125 <dd>This attribute indicates that the source code contained a hint that inlining
1126 this function is desirable (such as the "inline" keyword in C/C++). It
1127 is just a hint; it imposes no requirements on the inliner.</dd>
1128
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1129 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1130 <dd>This attribute indicates that the inliner should never inline this
1131 function in any situation. This attribute may not be used together with
1132 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1133
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1134 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1135 <dd>This attribute suggests that optimization passes and code generator passes
1136 make choices that keep the code size of this function low, and otherwise
1137 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1138
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1139 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1140 <dd>This function attribute indicates that the function never returns
1141 normally. This produces undefined behavior at runtime if the function
1142 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1143
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1144 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1145 <dd>This function attribute indicates that the function never returns with an
1146 unwind or exceptional control flow. If the function does unwind, its
1147 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1148
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1149 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1150 <dd>This attribute indicates that the function computes its result (or decides
1151 to unwind an exception) based strictly on its arguments, without
1152 dereferencing any pointer arguments or otherwise accessing any mutable
1153 state (e.g. memory, control registers, etc) visible to caller functions.
1154 It does not write through any pointer arguments
1155 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1156 changes any state visible to callers. This means that it cannot unwind
1157 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1158 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1159
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1160 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1161 <dd>This attribute indicates that the function does not write through any
1162 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1163 arguments) or otherwise modify any state (e.g. memory, control registers,
1164 etc) visible to caller functions. It may dereference pointer arguments
1165 and read state that may be set in the caller. A readonly function always
1166 returns the same value (or unwinds an exception identically) when called
1167 with the same set of arguments and global state. It cannot unwind an
1168 exception by calling the <tt>C++</tt> exception throwing methods, but may
1169 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1170
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This attribute indicates that the function should emit a stack smashing
1173 protector. It is in the form of a "canary"&mdash;a random value placed on
1174 the stack before the local variables that's checked upon return from the
1175 function to see if it has been overwritten. A heuristic is used to
1176 determine if a function needs stack protectors or not.<br>
1177<br>
1178 If a function that has an <tt>ssp</tt> attribute is inlined into a
1179 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1180 function will have an <tt>ssp</tt> attribute.</dd>
1181
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1182 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1183 <dd>This attribute indicates that the function should <em>always</em> emit a
1184 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1185 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1186<br>
1187 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1188 function that doesn't have an <tt>sspreq</tt> attribute or which has
1189 an <tt>ssp</tt> attribute, then the resulting function will have
1190 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1191
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1192 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1193 <dd>This attribute indicates that the code generator should not use a red
1194 zone, even if the target-specific ABI normally permits it.</dd>
1195
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1197 <dd>This attributes disables implicit floating point instructions.</dd>
1198
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1199 <dt><tt><b>naked</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1200 <dd>This attribute disables prologue / epilogue emission for the function.
1201 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1202</dl>
1203
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1204</div>
1205
1206<!-- ======================================================================= -->
1207<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1208 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1209</div>
1210
1211<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1212
1213<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1214 the GCC "file scope inline asm" blocks. These blocks are internally
1215 concatenated by LLVM and treated as a single unit, but may be separated in
1216 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1217
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1218<div class="doc_code">
1219<pre>
1220module asm "inline asm code goes here"
1221module asm "more can go here"
1222</pre>
1223</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1224
1225<p>The strings can contain any character by escaping non-printable characters.
1226 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]1227 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1228
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1229<p>The inline asm code is simply printed to the machine code .s file when
1230 assembly code is generated.</p>
1231
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1232</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1233
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1234<!-- ======================================================================= -->
1235<div class="doc_subsection">
1236 <a name="datalayout">Data Layout</a>
1237</div>
1238
1239<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1240
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1241<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1242 data is to be laid out in memory. The syntax for the data layout is
1243 simply:</p>
1244
1245<div class="doc_code">
1246<pre>
1247target datalayout = "<i>layout specification</i>"
1248</pre>
1249</div>
1250
1251<p>The <i>layout specification</i> consists of a list of specifications
1252 separated by the minus sign character ('-'). Each specification starts with
1253 a letter and may include other information after the letter to define some
1254 aspect of the data layout. The specifications accepted are as follows:</p>
1255
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1256<dl>
1257 <dt><tt>E</tt></dt>
1258 <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]1259 bits with the most significance have the lowest address location.</dd>
1260
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1261 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1262 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1263 the bits with the least significance have the lowest address
1264 location.</dd>
1265
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1266 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1267 <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]1268 <i>preferred</i> alignments. All sizes are in bits. Specifying
1269 the <i>pref</i> alignment is optional. If omitted, the
1270 preceding <tt>:</tt> should be omitted too.</dd>
1271
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1272 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1273 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1274 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1275
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1276 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1277 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1278 <i>size</i>.</dd>
1279
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1280 <dt><tt>f<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 floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1283 (double).</dd>
1284
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1285 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1286 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1287 <i>size</i>.</dd>
1288
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1289 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1290 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1291 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1292
1293 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1294 <dd>This specifies a set of native integer widths for the target CPU
1295 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1296 "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]1297 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1298 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1299</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1300
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1301<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1302 default set of specifications which are then (possibly) overriden by the
1303 specifications in the <tt>datalayout</tt> keyword. The default specifications
1304 are given in this list:</p>
1305
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1306<ul>
1307 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1308 <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]1309 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1310 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1311 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1312 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1313 <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]1314 alignment of 64-bits</li>
1315 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1316 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1317 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1318 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1319 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1320 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1321</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1322
1323<p>When LLVM is determining the alignment for a given type, it uses the
1324 following rules:</p>
1325
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1326<ol>
1327 <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]1328 specification is used.</li>
1329
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1330 <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]1331 smallest integer type that is larger than the bitwidth of the sought type
1332 is used. If none of the specifications are larger than the bitwidth then
1333 the the largest integer type is used. For example, given the default
1334 specifications above, the i7 type will use the alignment of i8 (next
1335 largest) while both i65 and i256 will use the alignment of i64 (largest
1336 specified).</li>
1337
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1338 <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]1339 largest vector type that is smaller than the sought vector type will be
1340 used as a fall back. This happens because &lt;128 x double&gt; can be
1341 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1342</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1343
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1344</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1345
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1346<!-- ======================================================================= -->
1347<div class="doc_subsection">
1348 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1349</div>
1350
1351<div class="doc_text">
1352
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1353<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1354with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1355is undefined. Pointer values are associated with address ranges
1356according to the following rules:</p>
1357
1358<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1359 <li>A pointer value formed from a
1360 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1361 is associated with the addresses associated with the first operand
1362 of the <tt>getelementptr</tt>.</li>
1363 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1364 range of the variable's storage.</li>
1365 <li>The result value of an allocation instruction is associated with
1366 the address range of the allocated storage.</li>
1367 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1368 no address.</li>
1369 <li>A pointer value formed by an
1370 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1371 address ranges of all pointer values that contribute (directly or
1372 indirectly) to the computation of the pointer's value.</li>
1373 <li>The result value of a
1374 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1375 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1376 <li>An integer constant other than zero or a pointer value returned
1377 from a function not defined within LLVM may be associated with address
1378 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1379 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1380 allocated by mechanisms provided by LLVM.</li>
1381 </ul>
1382
1383<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1384<tt><a href="#i_load">load</a></tt> merely indicates the size and
1385alignment of the memory from which to load, as well as the
1386interpretation of the value. The first operand of a
1387<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1388and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1389
1390<p>Consequently, type-based alias analysis, aka TBAA, aka
1391<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1392LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1393additional information which specialized optimization passes may use
1394to implement type-based alias analysis.</p>
1395
1396</div>
1397
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1398<!-- ======================================================================= -->
1399<div class="doc_subsection">
1400 <a name="volatile">Volatile Memory Accesses</a>
1401</div>
1402
1403<div class="doc_text">
1404
1405<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1406href="#i_store"><tt>store</tt></a>s, and <a
1407href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1408The optimizers must not change the number of volatile operations or change their
1409order of execution relative to other volatile operations. The optimizers
1410<i>may</i> change the order of volatile operations relative to non-volatile
1411operations. This is not Java's "volatile" and has no cross-thread
1412synchronization behavior.</p>
1413
1414</div>
1415
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1416<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1417<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1418<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1419
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1420<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1421
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1422<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1423 intermediate representation. Being typed enables a number of optimizations
1424 to be performed on the intermediate representation directly, without having
1425 to do extra analyses on the side before the transformation. A strong type
1426 system makes it easier to read the generated code and enables novel analyses
1427 and transformations that are not feasible to perform on normal three address
1428 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1429
1430</div>
1431
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1432<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1433<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1434Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1435
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1436<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1437
1438<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1439
1440<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1441 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1442 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1443 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1444 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1445 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1446 </tr>
1447 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1448 <td><a href="#t_floating">floating point</a></td>
1449 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1450 </tr>
1451 <tr>
1452 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1453 <td><a href="#t_integer">integer</a>,
1454 <a href="#t_floating">floating point</a>,
1455 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1456 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1457 <a href="#t_struct">structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1458 <a href="#t_union">union</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1459 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1460 <a href="#t_label">label</a>,
1461 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1462 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1463 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1464 <tr>
1465 <td><a href="#t_primitive">primitive</a></td>
1466 <td><a href="#t_label">label</a>,
1467 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1468 <a href="#t_floating">floating point</a>,
1469 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1470 </tr>
1471 <tr>
1472 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1473 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1474 <a href="#t_function">function</a>,
1475 <a href="#t_pointer">pointer</a>,
1476 <a href="#t_struct">structure</a>,
1477 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1478 <a href="#t_union">union</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1479 <a href="#t_vector">vector</a>,
1480 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1481 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1482 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1483 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1484</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1485
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1486<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1487 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1488 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1489
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1490</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1491
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1492<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1493<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1494
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1495<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1496
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1497<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1498 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1499
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1500</div>
1501
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1502<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1503<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1504
1505<div class="doc_text">
1506
1507<h5>Overview:</h5>
1508<p>The integer type is a very simple type that simply specifies an arbitrary
1509 bit width for the integer type desired. Any bit width from 1 bit to
1510 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1511
1512<h5>Syntax:</h5>
1513<pre>
1514 iN
1515</pre>
1516
1517<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1518 value.</p>
1519
1520<h5>Examples:</h5>
1521<table class="layout">
1522 <tr class="layout">
1523 <td class="left"><tt>i1</tt></td>
1524 <td class="left">a single-bit integer.</td>
1525 </tr>
1526 <tr class="layout">
1527 <td class="left"><tt>i32</tt></td>
1528 <td class="left">a 32-bit integer.</td>
1529 </tr>
1530 <tr class="layout">
1531 <td class="left"><tt>i1942652</tt></td>
1532 <td class="left">a really big integer of over 1 million bits.</td>
1533 </tr>
1534</table>
1535
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1536</div>
1537
1538<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1539<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1540
1541<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1542
1543<table>
1544 <tbody>
1545 <tr><th>Type</th><th>Description</th></tr>
1546 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1547 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1548 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1549 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1550 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1551 </tbody>
1552</table>
1553
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1554</div>
1555
1556<!-- _______________________________________________________________________ -->
1557<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1558
1559<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1560
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1561<h5>Overview:</h5>
1562<p>The void type does not represent any value and has no size.</p>
1563
1564<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1565<pre>
1566 void
1567</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1568
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1569</div>
1570
1571<!-- _______________________________________________________________________ -->
1572<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1573
1574<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1575
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1576<h5>Overview:</h5>
1577<p>The label type represents code labels.</p>
1578
1579<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1580<pre>
1581 label
1582</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1583
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1584</div>
1585
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1586<!-- _______________________________________________________________________ -->
1587<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1588
1589<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1590
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1591<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1592<p>The metadata type represents embedded metadata. No derived types may be
1593 created from metadata except for <a href="#t_function">function</a>
1594 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1595
1596<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1597<pre>
1598 metadata
1599</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1600
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1601</div>
1602
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1603
1604<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1605<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1606
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1607<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1608
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1609<p>The real power in LLVM comes from the derived types in the system. This is
1610 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1611 useful types. Each of these types contain one or more element types which
1612 may be a primitive type, or another derived type. For example, it is
1613 possible to have a two dimensional array, using an array as the element type
1614 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1615
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1616
1617</div>
1618
1619<!-- _______________________________________________________________________ -->
1620<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1621
1622<div class="doc_text">
1623
1624<p>Aggregate Types are a subset of derived types that can contain multiple
1625 member types. <a href="#t_array">Arrays</a>,
1626 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1627 <a href="#t_union">unions</a> are aggregate types.</p>
1628
1629</div>
1630
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1631</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1632
1633<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1634<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1635
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1636<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1637
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1638<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1639<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1640 sequentially in memory. The array type requires a size (number of elements)
1641 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1642
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1643<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1644<pre>
1645 [&lt;# elements&gt; x &lt;elementtype&gt;]
1646</pre>
1647
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1648<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1649 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1650
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1651<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1652<table class="layout">
1653 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1654 <td class="left"><tt>[40 x i32]</tt></td>
1655 <td class="left">Array of 40 32-bit integer values.</td>
1656 </tr>
1657 <tr class="layout">
1658 <td class="left"><tt>[41 x i32]</tt></td>
1659 <td class="left">Array of 41 32-bit integer values.</td>
1660 </tr>
1661 <tr class="layout">
1662 <td class="left"><tt>[4 x i8]</tt></td>
1663 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1664 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1665</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1666<p>Here are some examples of multidimensional arrays:</p>
1667<table class="layout">
1668 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1669 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1670 <td class="left">3x4 array of 32-bit integer values.</td>
1671 </tr>
1672 <tr class="layout">
1673 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1674 <td class="left">12x10 array of single precision floating point values.</td>
1675 </tr>
1676 <tr class="layout">
1677 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1678 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1679 </tr>
1680</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1681
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1682<p>There is no restriction on indexing beyond the end of the array implied by
1683 a static type (though there are restrictions on indexing beyond the bounds
1684 of an allocated object in some cases). This means that single-dimension
1685 'variable sized array' addressing can be implemented in LLVM with a zero
1686 length array type. An implementation of 'pascal style arrays' in LLVM could
1687 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1688
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1689</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1690
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1691<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1692<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1693
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1694<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1695
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1696<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1697<p>The function type can be thought of as a function signature. It consists of
1698 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]1699 function type is a scalar type, a void type, a struct type, or a union
1700 type. If the return type is a struct type then all struct elements must be
1701 of first class types, and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1702
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1703<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1704<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1705 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1706</pre>
1707
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1708<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]1709 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1710 which indicates that the function takes a variable number of arguments.
1711 Variable argument functions can access their arguments with
1712 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1713 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1714 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1715
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1716<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1717<table class="layout">
1718 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1719 <td class="left"><tt>i32 (i32)</tt></td>
1720 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1721 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1722 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1723 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1724 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1725 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1726 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1727 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1728 </td>
1729 </tr><tr class="layout">
1730 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1731 <td class="left">A vararg function that takes at least one
1732 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1733 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1734 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1735 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1736 </tr><tr class="layout">
1737 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1738 <td class="left">A function taking an <tt>i32</tt>, returning a
1739 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1740 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1741 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1742</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1743
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1744</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1745
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1746<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1747<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1748
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1749<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1750
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1751<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1752<p>The structure type is used to represent a collection of data members together
1753 in memory. The packing of the field types is defined to match the ABI of the
1754 underlying processor. The elements of a structure may be any type that has a
1755 size.</p>
1756
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1757<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1758 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1759 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1760 Structures in registers are accessed using the
1761 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1762 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1763<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1764<pre>
1765 { &lt;type list&gt; }
1766</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1767
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1768<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1769<table class="layout">
1770 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1771 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1772 <td class="left">A triple of three <tt>i32</tt> values</td>
1773 </tr><tr class="layout">
1774 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1775 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1776 second element is a <a href="#t_pointer">pointer</a> to a
1777 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1778 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1779 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1780</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1781
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1782</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1783
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1784<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1785<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1786</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1787
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1788<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1789
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1790<h5>Overview:</h5>
1791<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1792 together in memory. There is no padding between fields. Further, the
1793 alignment of a packed structure is 1 byte. The elements of a packed
1794 structure may be any type that has a size.</p>
1795
1796<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1797 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1798 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1799
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1800<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1801<pre>
1802 &lt; { &lt;type list&gt; } &gt;
1803</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1804
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1805<h5>Examples:</h5>
1806<table class="layout">
1807 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1808 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1809 <td class="left">A triple of three <tt>i32</tt> values</td>
1810 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1811 <td class="left">
1812<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1813 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1814 second element is a <a href="#t_pointer">pointer</a> to a
1815 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1816 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1817 </tr>
1818</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1819
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1820</div>
1821
1822<!-- _______________________________________________________________________ -->
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1823<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1824
1825<div class="doc_text">
1826
1827<h5>Overview:</h5>
1828<p>A union type describes an object with size and alignment suitable for
1829 an object of any one of a given set of types (also known as an "untagged"
1830 union). It is similar in concept and usage to a
1831 <a href="#t_struct">struct</a>, except that all members of the union
1832 have an offset of zero. The elements of a union may be any type that has a
1833 size. Unions must have at least one member - empty unions are not allowed.
1834 </p>
1835
1836<p>The size of the union as a whole will be the size of its largest member,
1837 and the alignment requirements of the union as a whole will be the largest
1838 alignment requirement of any member.</p>
1839
Dan Gohman2eddfef2010-02-25 16:51:31 +0000[diff] [blame]1840<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]1841 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1842 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1843 Since all members are at offset zero, the getelementptr instruction does
1844 not affect the address, only the type of the resulting pointer.</p>
1845
1846<h5>Syntax:</h5>
1847<pre>
1848 union { &lt;type list&gt; }
1849</pre>
1850
1851<h5>Examples:</h5>
1852<table class="layout">
1853 <tr class="layout">
1854 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1855 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1856 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1857 </tr><tr class="layout">
1858 <td class="left">
1859 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1860 <td class="left">A union, where the first element is a <tt>float</tt> and the
1861 second element is a <a href="#t_pointer">pointer</a> to a
1862 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1863 an <tt>i32</tt>.</td>
1864 </tr>
1865</table>
1866
1867</div>
1868
1869<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1870<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1871
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1872<div class="doc_text">
1873
1874<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1875<p>The pointer type is used to specify memory locations.
1876 Pointers are commonly used to reference objects in memory.</p>
1877
1878<p>Pointer types may have an optional address space attribute defining the
1879 numbered address space where the pointed-to object resides. The default
1880 address space is number zero. The semantics of non-zero address
1881 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1882
1883<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1884 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1885
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1886<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1887<pre>
1888 &lt;type&gt; *
1889</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1890
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1891<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1892<table class="layout">
1893 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1894 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1895 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1896 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1897 </tr>
1898 <tr class="layout">
1899 <td class="left"><tt>i32 (i32 *) *</tt></td>
1900 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1901 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1902 <tt>i32</tt>.</td>
1903 </tr>
1904 <tr class="layout">
1905 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1906 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1907 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1908 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1909</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1910
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1911</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1912
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1913<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1914<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1915
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1916<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1917
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1918<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1919<p>A vector type is a simple derived type that represents a vector of elements.
1920 Vector types are used when multiple primitive data are operated in parallel
1921 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1922 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1923 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1924
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1925<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1926<pre>
1927 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1928</pre>
1929
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1930<p>The number of elements is a constant integer value; elementtype may be any
1931 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1932
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1933<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1934<table class="layout">
1935 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1936 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1937 <td class="left">Vector of 4 32-bit integer values.</td>
1938 </tr>
1939 <tr class="layout">
1940 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1941 <td class="left">Vector of 8 32-bit floating-point values.</td>
1942 </tr>
1943 <tr class="layout">
1944 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1945 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1946 </tr>
1947</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1948
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1949</div>
1950
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1951<!-- _______________________________________________________________________ -->
1952<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1953<div class="doc_text">
1954
1955<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1956<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1957 corresponds (for example) to the C notion of a forward declared structure
1958 type. In LLVM, opaque types can eventually be resolved to any type (not just
1959 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1960
1961<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1962<pre>
1963 opaque
1964</pre>
1965
1966<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1967<table class="layout">
1968 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1969 <td class="left"><tt>opaque</tt></td>
1970 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1971 </tr>
1972</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1973
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1974</div>
1975
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1976<!-- ======================================================================= -->
1977<div class="doc_subsection">
1978 <a name="t_uprefs">Type Up-references</a>
1979</div>
1980
1981<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1982
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1983<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1984<p>An "up reference" allows you to refer to a lexically enclosing type without
1985 requiring it to have a name. For instance, a structure declaration may
1986 contain a pointer to any of the types it is lexically a member of. Example
1987 of up references (with their equivalent as named type declarations)
1988 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1989
1990<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1991 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1992 { \2 }* %y = type { %y }*
1993 \1* %z = type %z*
1994</pre>
1995
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1996<p>An up reference is needed by the asmprinter for printing out cyclic types
1997 when there is no declared name for a type in the cycle. Because the
1998 asmprinter does not want to print out an infinite type string, it needs a
1999 syntax to handle recursive types that have no names (all names are optional
2000 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2001
2002<h5>Syntax:</h5>
2003<pre>
2004 \&lt;level&gt;
2005</pre>
2006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2007<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]2008
2009<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2010<table class="layout">
2011 <tr class="layout">
2012 <td class="left"><tt>\1*</tt></td>
2013 <td class="left">Self-referential pointer.</td>
2014 </tr>
2015 <tr class="layout">
2016 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2017 <td class="left">Recursive structure where the upref refers to the out-most
2018 structure.</td>
2019 </tr>
2020</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2021
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2022</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2023
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2024<!-- *********************************************************************** -->
2025<div class="doc_section"> <a name="constants">Constants</a> </div>
2026<!-- *********************************************************************** -->
2027
2028<div class="doc_text">
2029
2030<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2031 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2032
2033</div>
2034
2035<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2036<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2037
2038<div class="doc_text">
2039
2040<dl>
2041 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2042 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2043 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2044
2045 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2046 <dd>Standard integers (such as '4') are constants of
2047 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2048 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2049
2050 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2051 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2052 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2053 notation (see below). The assembler requires the exact decimal value of a
2054 floating-point constant. For example, the assembler accepts 1.25 but
2055 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2056 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2057
2058 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2059 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2060 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2061</dl>
2062
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2063<p>The one non-intuitive notation for constants is the hexadecimal form of
2064 floating point constants. For example, the form '<tt>double
2065 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2066 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2067 constants are required (and the only time that they are generated by the
2068 disassembler) is when a floating point constant must be emitted but it cannot
2069 be represented as a decimal floating point number in a reasonable number of
2070 digits. For example, NaN's, infinities, and other special values are
2071 represented in their IEEE hexadecimal format so that assembly and disassembly
2072 do not cause any bits to change in the constants.</p>
2073
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2074<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2075 represented using the 16-digit form shown above (which matches the IEEE754
2076 representation for double); float values must, however, be exactly
2077 representable as IEE754 single precision. Hexadecimal format is always used
2078 for long double, and there are three forms of long double. The 80-bit format
2079 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2080 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2081 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2082 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2083 currently supported target uses this format. Long doubles will only work if
2084 they match the long double format on your target. All hexadecimal formats
2085 are big-endian (sign bit at the left).</p>
2086
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2087</div>
2088
2089<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2090<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2091<a name="aggregateconstants"></a> <!-- old anchor -->
2092<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2093</div>
2094
2095<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2096
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2097<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2098 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2099
2100<dl>
2101 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2102 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2103 type definitions (a comma separated list of elements, surrounded by braces
2104 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2105 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2106 Structure constants must have <a href="#t_struct">structure type</a>, and
2107 the number and types of elements must match those specified by the
2108 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2109
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2110 <dt><b>Union constants</b></dt>
2111 <dd>Union constants are represented with notation similar to a structure with
2112 a single element - that is, a single typed element surrounded
2113 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2114 <a href="#t_union">union type</a> can be initialized with a single-element
2115 struct as long as the type of the struct element matches the type of
2116 one of the union members.</dd>
2117
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2118 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2119 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2120 definitions (a comma separated list of elements, surrounded by square
2121 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2122 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2123 the number and types of elements must match those specified by the
2124 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2125
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2126 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2127 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2128 definitions (a comma separated list of elements, surrounded by
2129 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2130 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2131 have <a href="#t_vector">vector type</a>, and the number and types of
2132 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2133
2134 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2135 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2136 value to zero of <em>any</em> type, including scalar and
2137 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2138 This is often used to avoid having to print large zero initializers
2139 (e.g. for large arrays) and is always exactly equivalent to using explicit
2140 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2141
2142 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2143 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2144 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2145 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2146 be interpreted as part of the instruction stream, metadata is a place to
2147 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2148</dl>
2149
2150</div>
2151
2152<!-- ======================================================================= -->
2153<div class="doc_subsection">
2154 <a name="globalconstants">Global Variable and Function Addresses</a>
2155</div>
2156
2157<div class="doc_text">
2158
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2159<p>The addresses of <a href="#globalvars">global variables</a>
2160 and <a href="#functionstructure">functions</a> are always implicitly valid
2161 (link-time) constants. These constants are explicitly referenced when
2162 the <a href="#identifiers">identifier for the global</a> is used and always
2163 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2164 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2165
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2166<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2167<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2168@X = global i32 17
2169@Y = global i32 42
2170@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2171</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2172</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2173
2174</div>
2175
2176<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2177<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2178<div class="doc_text">
2179
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2180<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]2181 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2182 Undefined values may be of any type (other than label or void) and be used
2183 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2184
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2185<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2186 program is well defined no matter what value is used. This gives the
2187 compiler more freedom to optimize. Here are some examples of (potentially
2188 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2189
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2190
2191<div class="doc_code">
2192<pre>
2193 %A = add %X, undef
2194 %B = sub %X, undef
2195 %C = xor %X, undef
2196Safe:
2197 %A = undef
2198 %B = undef
2199 %C = undef
2200</pre>
2201</div>
2202
2203<p>This is safe because all of the output bits are affected by the undef bits.
2204Any output bit can have a zero or one depending on the input bits.</p>
2205
2206<div class="doc_code">
2207<pre>
2208 %A = or %X, undef
2209 %B = and %X, undef
2210Safe:
2211 %A = -1
2212 %B = 0
2213Unsafe:
2214 %A = undef
2215 %B = undef
2216</pre>
2217</div>
2218
2219<p>These logical operations have bits that are not always affected by the input.
2220For example, if "%X" has a zero bit, then the output of the 'and' operation will
2221always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2222such, 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]2223However, it is safe to assume that all bits of the undef could be 0, and
2224optimize the and to 0. Likewise, it is safe to assume that all the bits of
2225the 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]2226-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2227
2228<div class="doc_code">
2229<pre>
2230 %A = select undef, %X, %Y
2231 %B = select undef, 42, %Y
2232 %C = select %X, %Y, undef
2233Safe:
2234 %A = %X (or %Y)
2235 %B = 42 (or %Y)
2236 %C = %Y
2237Unsafe:
2238 %A = undef
2239 %B = undef
2240 %C = undef
2241</pre>
2242</div>
2243
2244<p>This set of examples show that undefined select (and conditional branch)
2245conditions can go "either way" but they have to come from one of the two
2246operands. In the %A example, if %X and %Y were both known to have a clear low
2247bit, then %A would have to have a cleared low bit. However, in the %C example,
2248the optimizer is allowed to assume that the undef operand could be the same as
2249%Y, allowing the whole select to be eliminated.</p>
2250
2251
2252<div class="doc_code">
2253<pre>
2254 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2255
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2256 %B = undef
2257 %C = xor %B, %B
2258
2259 %D = undef
2260 %E = icmp lt %D, 4
2261 %F = icmp gte %D, 4
2262
2263Safe:
2264 %A = undef
2265 %B = undef
2266 %C = undef
2267 %D = undef
2268 %E = undef
2269 %F = undef
2270</pre>
2271</div>
2272
2273<p>This example points out that two undef operands are not necessarily the same.
2274This can be surprising to people (and also matches C semantics) where they
2275assume that "X^X" is always zero, even if X is undef. This isn't true for a
2276number of reasons, but the short answer is that an undef "variable" can
2277arbitrarily change its value over its "live range". This is true because the
2278"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2279logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2280so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2281to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2282would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2283
2284<div class="doc_code">
2285<pre>
2286 %A = fdiv undef, %X
2287 %B = fdiv %X, undef
2288Safe:
2289 %A = undef
2290b: unreachable
2291</pre>
2292</div>
2293
2294<p>These examples show the crucial difference between an <em>undefined
2295value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2296allowed to have an arbitrary bit-pattern. This means that the %A operation
2297can be constant folded to undef because the undef could be an SNaN, and fdiv is
2298not (currently) defined on SNaN's. However, in the second example, we can make
2299a more aggressive assumption: because the undef is allowed to be an arbitrary
2300value, 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]2301has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2302does not execute at all. This allows us to delete the divide and all code after
2303it: since the undefined operation "can't happen", the optimizer can assume that
2304it occurs in dead code.
2305</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2306
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2307<div class="doc_code">
2308<pre>
2309a: store undef -> %X
2310b: store %X -> undef
2311Safe:
2312a: &lt;deleted&gt;
2313b: unreachable
2314</pre>
2315</div>
2316
2317<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2318can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2319overwritten with bits that happen to match what was already there. However, a
2320store "to" an undefined location could clobber arbitrary memory, therefore, it
2321has undefined behavior.</p>
2322
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2323</div>
2324
2325<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2326<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2327<div class="doc_text">
2328
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2329<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2330 instead of representing an unspecified bit pattern, they represent the
2331 fact that an instruction or constant expression which cannot evoke side
2332 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2333 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2334
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame^]2335<p>Any value other than a non-intrinsic call, invoke, or phi with a trap
2336 operand has trap as its result value. Any instruction with
2337 a trap operand which may have side effects emits those side effects as
2338 if it had an undef operand instead. If the side effects are externally
2339 visible, the behavior is undefined.</p>
2340
2341<p>Trap values may be stored to memory; a load from memory including any
2342 part of a trap value results in a (full) trap value.</p>
2343
2344<p>For example:</p>
2345
2346<!-- FIXME: In the case of multiple threads, this only applies to loads from
2347 the same thread as the store, or loads which are sequenced after the
2348 store by synchronization. -->
2349
2350<div class="doc_code">
2351<pre>
2352%trap = sub nuw i32 0, 1 ; Results in a trap value.
2353%still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2354%trap_yet_again = getelementptr i32* @h, i32 %still_trap
2355store i32 0, i32* %trap_yet_again ; undefined behavior
2356
2357volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2358%trap2 = load i32* @g ; Returns a trap value, not just undef.
2359%narrowaddr = bitcast i32* @g to i16*
2360%wideaddr = bitcast i32* @g to i64*
2361%trap3 = load 16* %narrowaddr ; Returns a trap value
2362%trap4 = load i64* %widaddr ; Returns a trap value, not partial trap.
2363</pre>
2364</div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2365
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2366<p>If a <a href="#i_br"><tt>br</tt></a> or
2367 <a href="#i_switch"><tt>switch</tt></a> instruction has a trap value
2368 operand, all non-phi non-void instructions which control-depend on it
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame^]2369 have trap as their result value. A <a href="#i_phi"><tt>phi</tt></a>
2370 node with an incoming value associated with a control edge which is
2371 control-dependent on it has trap as its result value when control is
2372 transferred from that block. If any instruction which control-depends
2373 on the <tt>br</tt> or <tt>switch</tt> invokes externally visible side
2374 effects, the behavior of the program is undefined. For example:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2375
2376<!-- FIXME: What about exceptions thrown from control-dependent instrs? -->
2377
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame^]2378<div class="doc_code">
2379<pre>
2380entry:
2381 %trap = sub nuw i32 0, 1 ; Results in a trap value.
2382 %cmp = icmp i32 slt %trap, 0 ; Still trap.
2383 %br i1 %cmp, %true, %end ; Branch to either destination.
2384
2385true:
2386 volatile store i32 0, i32* @g ; Externally visible side effects
2387 ; control-dependent on %cmp.
2388 ; Undefined behavior.
2389 br label %end
2390
2391end:
2392 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2393 ; Both edges into this PHI are
2394 ; control-dependent on %cmp, so this
2395 ; results in a trap value.
2396
2397 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2398 ; so this is defined (ignoring earlier
2399 ; undefined behavior in this example).
2400
2401</pre>
2402</div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2403
2404<p>There is currently no way of representing a trap constant in the IR; they
2405 only exist when produced by certain instructions, such as an
2406 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag
2407 set, when overflow occurs.</p>
2408
2409</div>
2410
2411<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2412<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2413 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2414<div class="doc_text">
2415
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2416<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2417
2418<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2419 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2420 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2421
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2422<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2423 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2424 against null. Pointer equality tests between labels addresses is undefined
2425 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2426 equal to the null pointer. This may also be passed around as an opaque
2427 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2428 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2429 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2430
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2431<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2432 using the value as the operand to an inline assembly, but that is target
2433 specific.
2434 </p>
2435
2436</div>
2437
2438
2439<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2440<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2441</div>
2442
2443<div class="doc_text">
2444
2445<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2446 to be used as constants. Constant expressions may be of
2447 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2448 operation that does not have side effects (e.g. load and call are not
2449 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2450
2451<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2452 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2453 <dd>Truncate a constant to another type. The bit size of CST must be larger
2454 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2455
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2456 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2457 <dd>Zero extend a constant to another type. The bit size of CST must be
2458 smaller or equal to the bit size of TYPE. Both types must be
2459 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2460
2461 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2462 <dd>Sign extend a constant to another type. The bit size of CST must be
2463 smaller or equal to the bit size of TYPE. Both types must be
2464 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2465
2466 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2467 <dd>Truncate a floating point constant to another floating point type. The
2468 size of CST must be larger than the size of TYPE. Both types must be
2469 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2470
2471 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2472 <dd>Floating point extend a constant to another type. The size of CST must be
2473 smaller or equal to the size of TYPE. Both types must be floating
2474 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2475
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2476 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2477 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2478 constant. TYPE must be a scalar or vector integer type. CST must be of
2479 scalar or vector floating point type. Both CST and TYPE must be scalars,
2480 or vectors of the same number of elements. If the value won't fit in the
2481 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2482
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2483 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2484 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2485 constant. TYPE must be a scalar or vector integer type. CST must be of
2486 scalar or vector floating point type. Both CST and TYPE must be scalars,
2487 or vectors of the same number of elements. If the value won't fit in the
2488 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2489
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2490 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2491 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2492 constant. TYPE must be a scalar or vector floating point type. CST must be
2493 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2494 vectors of the same number of elements. If the value won't fit in the
2495 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2496
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2497 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2498 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2499 constant. TYPE must be a scalar or vector floating point type. CST must be
2500 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2501 vectors of the same number of elements. If the value won't fit in the
2502 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2503
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2504 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2505 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2506 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2507 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2508 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2509
2510 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2511 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2512 type. CST must be of integer type. The CST value is zero extended,
2513 truncated, or unchanged to make it fit in a pointer size. This one is
2514 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2515
2516 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2517 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2518 are the same as those for the <a href="#i_bitcast">bitcast
2519 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2520
2521 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2522 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2523 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2524 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2525 instruction, the index list may have zero or more indexes, which are
2526 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2527
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2528 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2529 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2530
2531 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2532 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2533
2534 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2535 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2536
2537 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2538 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2539 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2540
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2541 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2542 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2543 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2544
2545 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2546 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2547 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2548
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2549 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2550 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2551 be any of the <a href="#binaryops">binary</a>
2552 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2553 on operands are the same as those for the corresponding instruction
2554 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2555</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2556
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2557</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2558
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2559<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2560<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2561<!-- *********************************************************************** -->
2562
2563<!-- ======================================================================= -->
2564<div class="doc_subsection">
2565<a name="inlineasm">Inline Assembler Expressions</a>
2566</div>
2567
2568<div class="doc_text">
2569
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2570<p>LLVM supports inline assembler expressions (as opposed
2571 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2572 a special value. This value represents the inline assembler as a string
2573 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2574 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2575 expression has side effects, and a flag indicating whether the function
2576 containing the asm needs to align its stack conservatively. An example
2577 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2578
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2579<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2580<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2581i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2582</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2583</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2584
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2585<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2586 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2587 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2588
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2589<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2590<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2591%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]2592</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2593</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2594
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2595<p>Inline asms with side effects not visible in the constraint list must be
2596 marked as having side effects. This is done through the use of the
2597 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2598
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2599<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2600<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2601call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2602</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2603</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2604
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2605<p>In some cases inline asms will contain code that will not work unless the
2606 stack is aligned in some way, such as calls or SSE instructions on x86,
2607 yet will not contain code that does that alignment within the asm.
2608 The compiler should make conservative assumptions about what the asm might
2609 contain and should generate its usual stack alignment code in the prologue
2610 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2611
2612<div class="doc_code">
2613<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2614call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2615</pre>
2616</div>
2617
2618<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2619 first.</p>
2620
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2621<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2622 documented here. Constraints on what can be done (e.g. duplication, moving,
2623 etc need to be documented). This is probably best done by reference to
2624 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2625</div>
2626
2627<div class="doc_subsubsection">
2628<a name="inlineasm_md">Inline Asm Metadata</a>
2629</div>
2630
2631<div class="doc_text">
2632
2633<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2634 attached to it that contains a constant integer. If present, the code
2635 generator will use the integer as the location cookie value when report
2636 errors through the LLVMContext error reporting mechanisms. This allows a
2637 front-end to corrolate backend errors that occur with inline asm back to the
2638 source code that produced it. For example:</p>
2639
2640<div class="doc_code">
2641<pre>
2642call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2643...
2644!42 = !{ i32 1234567 }
2645</pre>
2646</div>
2647
2648<p>It is up to the front-end to make sense of the magic numbers it places in the
2649 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2650
2651</div>
2652
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2653<!-- ======================================================================= -->
2654<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2655 Strings</a>
2656</div>
2657
2658<div class="doc_text">
2659
2660<p>LLVM IR allows metadata to be attached to instructions in the program that
2661 can convey extra information about the code to the optimizers and code
2662 generator. One example application of metadata is source-level debug
2663 information. There are two metadata primitives: strings and nodes. All
2664 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2665 preceding exclamation point ('<tt>!</tt>').</p>
2666
2667<p>A metadata string is a string surrounded by double quotes. It can contain
2668 any character by escaping non-printable characters with "\xx" where "xx" is
2669 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2670
2671<p>Metadata nodes are represented with notation similar to structure constants
2672 (a comma separated list of elements, surrounded by braces and preceded by an
2673 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2674 10}</tt>". Metadata nodes can have any values as their operand.</p>
2675
2676<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2677 metadata nodes, which can be looked up in the module symbol table. For
2678 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2679
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2680<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2681 function is using two metadata arguments.
2682
2683 <div class="doc_code">
2684 <pre>
2685 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2686 </pre>
2687 </div></p>
2688
2689<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2690 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2691
2692 <div class="doc_code">
2693 <pre>
2694 %indvar.next = add i64 %indvar, 1, !dbg !21
2695 </pre>
2696 </div></p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2697</div>
2698
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2699
2700<!-- *********************************************************************** -->
2701<div class="doc_section">
2702 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2703</div>
2704<!-- *********************************************************************** -->
2705
2706<p>LLVM has a number of "magic" global variables that contain data that affect
2707code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2708of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2709section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2710by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2711
2712<!-- ======================================================================= -->
2713<div class="doc_subsection">
2714<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2715</div>
2716
2717<div class="doc_text">
2718
2719<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2720href="#linkage_appending">appending linkage</a>. This array contains a list of
2721pointers to global variables and functions which may optionally have a pointer
2722cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2723
2724<pre>
2725 @X = global i8 4
2726 @Y = global i32 123
2727
2728 @llvm.used = appending global [2 x i8*] [
2729 i8* @X,
2730 i8* bitcast (i32* @Y to i8*)
2731 ], section "llvm.metadata"
2732</pre>
2733
2734<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2735compiler, assembler, and linker are required to treat the symbol as if there is
2736a reference to the global that it cannot see. For example, if a variable has
2737internal linkage and no references other than that from the <tt>@llvm.used</tt>
2738list, it cannot be deleted. This is commonly used to represent references from
2739inline asms and other things the compiler cannot "see", and corresponds to
2740"attribute((used))" in GNU C.</p>
2741
2742<p>On some targets, the code generator must emit a directive to the assembler or
2743object file to prevent the assembler and linker from molesting the symbol.</p>
2744
2745</div>
2746
2747<!-- ======================================================================= -->
2748<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2749<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2750</div>
2751
2752<div class="doc_text">
2753
2754<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2755<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2756touching the symbol. On targets that support it, this allows an intelligent
2757linker to optimize references to the symbol without being impeded as it would be
2758by <tt>@llvm.used</tt>.</p>
2759
2760<p>This is a rare construct that should only be used in rare circumstances, and
2761should not be exposed to source languages.</p>
2762
2763</div>
2764
2765<!-- ======================================================================= -->
2766<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2767<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2768</div>
2769
2770<div class="doc_text">
2771
2772<p>TODO: Describe this.</p>
2773
2774</div>
2775
2776<!-- ======================================================================= -->
2777<div class="doc_subsection">
2778<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2779</div>
2780
2781<div class="doc_text">
2782
2783<p>TODO: Describe this.</p>
2784
2785</div>
2786
2787
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2788<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2789<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2790<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2791
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2792<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2793
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2794<p>The LLVM instruction set consists of several different classifications of
2795 instructions: <a href="#terminators">terminator
2796 instructions</a>, <a href="#binaryops">binary instructions</a>,
2797 <a href="#bitwiseops">bitwise binary instructions</a>,
2798 <a href="#memoryops">memory instructions</a>, and
2799 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2800
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2801</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2802
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2803<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2804<div class="doc_subsection"> <a name="terminators">Terminator
2805Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2806
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2807<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2808
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2809<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2810 in a program ends with a "Terminator" instruction, which indicates which
2811 block should be executed after the current block is finished. These
2812 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2813 control flow, not values (the one exception being the
2814 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2815
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2816<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2817 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2818 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2819 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2820 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2821 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2822 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2823 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2824
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2825</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2826
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2827<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2828<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2829Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2830
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2831<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2832
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2833<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2834<pre>
2835 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]2836 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2837</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2838
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2839<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2840<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2841 a value) from a function back to the caller.</p>
2842
2843<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2844 value and then causes control flow, and one that just causes control flow to
2845 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2846
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2847<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2848<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2849 return value. The type of the return value must be a
2850 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2851
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2852<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2853 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2854 value or a return value with a type that does not match its type, or if it
2855 has a void return type and contains a '<tt>ret</tt>' instruction with a
2856 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2857
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2858<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2859<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2860 the calling function's context. If the caller is a
2861 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2862 instruction after the call. If the caller was an
2863 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2864 the beginning of the "normal" destination block. If the instruction returns
2865 a value, that value shall set the call or invoke instruction's return
2866 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2867
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2868<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2869<pre>
2870 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2871 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2872 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]2873</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2874
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2875</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2876<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2877<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2878
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2879<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2880
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2881<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2882<pre>
2883 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]2884</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2886<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2887<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2888 different basic block in the current function. There are two forms of this
2889 instruction, corresponding to a conditional branch and an unconditional
2890 branch.</p>
2891
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2892<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2893<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2894 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2895 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2896 target.</p>
2897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2898<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2899<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2900 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2901 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2902 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2903
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2904<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2905<pre>
2906Test:
2907 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2908 br i1 %cond, label %IfEqual, label %IfUnequal
2909IfEqual:
2910 <a href="#i_ret">ret</a> i32 1
2911IfUnequal:
2912 <a href="#i_ret">ret</a> i32 0
2913</pre>
2914
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2915</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2916
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2917<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2918<div class="doc_subsubsection">
2919 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2920</div>
2921
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2922<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2923
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2924<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2925<pre>
2926 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2927</pre>
2928
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2929<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2930<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]2931 several different places. It is a generalization of the '<tt>br</tt>'
2932 instruction, allowing a branch to occur to one of many possible
2933 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2934
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2935<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2936<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2937 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2938 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2939 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2940
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2941<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2942<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2943 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2944 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2945 transferred to the corresponding destination; otherwise, control flow is
2946 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2947
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2948<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2949<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2950 <tt>switch</tt> instruction, this instruction may be code generated in
2951 different ways. For example, it could be generated as a series of chained
2952 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2953
2954<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2955<pre>
2956 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2957 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2958 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2959
2960 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2961 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2962
2963 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2964 switch i32 %val, label %otherwise [ i32 0, label %onzero
2965 i32 1, label %onone
2966 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2967</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2968
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2969</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2970
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2971
2972<!-- _______________________________________________________________________ -->
2973<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2974 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2975</div>
2976
2977<div class="doc_text">
2978
2979<h5>Syntax:</h5>
2980<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2981 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]2982</pre>
2983
2984<h5>Overview:</h5>
2985
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2986<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2987 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2988 "<tt>address</tt>". Address must be derived from a <a
2989 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2990
2991<h5>Arguments:</h5>
2992
2993<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2994 rest of the arguments indicate the full set of possible destinations that the
2995 address may point to. Blocks are allowed to occur multiple times in the
2996 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2997
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2998<p>This destination list is required so that dataflow analysis has an accurate
2999 understanding of the CFG.</p>
3000
3001<h5>Semantics:</h5>
3002
3003<p>Control transfers to the block specified in the address argument. All
3004 possible destination blocks must be listed in the label list, otherwise this
3005 instruction has undefined behavior. This implies that jumps to labels
3006 defined in other functions have undefined behavior as well.</p>
3007
3008<h5>Implementation:</h5>
3009
3010<p>This is typically implemented with a jump through a register.</p>
3011
3012<h5>Example:</h5>
3013<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3014 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3015</pre>
3016
3017</div>
3018
3019
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3020<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3021<div class="doc_subsubsection">
3022 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3023</div>
3024
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3025<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3026
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3027<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3028<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3029 &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]3030 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3031</pre>
3032
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3033<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3034<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3035 function, with the possibility of control flow transfer to either the
3036 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3037 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3038 control flow will return to the "normal" label. If the callee (or any
3039 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3040 instruction, control is interrupted and continued at the dynamically nearest
3041 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3042
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3043<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3044<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3045
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3046<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3047 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3048 convention</a> the call should use. If none is specified, the call
3049 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3050
3051 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3052 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3053 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3054
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3055 <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]3056 function value being invoked. In most cases, this is a direct function
3057 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3058 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3059
3060 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3061 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3062
3063 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3064 signature argument types and parameter attributes. All arguments must be
3065 of <a href="#t_firstclass">first class</a> type. If the function
3066 signature indicates the function accepts a variable number of arguments,
3067 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3068
3069 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3070 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3071
3072 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3073 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3074
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3075 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3076 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3077 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3078</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3079
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3080<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3081<p>This instruction is designed to operate as a standard
3082 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3083 primary difference is that it establishes an association with a label, which
3084 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3085
3086<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3087 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3088 exception. Additionally, this is important for implementation of
3089 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3090
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3091<p>For the purposes of the SSA form, the definition of the value returned by the
3092 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3093 block to the "normal" label. If the callee unwinds then no return value is
3094 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3095
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3096<p>Note that the code generator does not yet completely support unwind, and
3097that the invoke/unwind semantics are likely to change in future versions.</p>
3098
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3099<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3100<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3101 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3102 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3103 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3104 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3105</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3106
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3107</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3108
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3109<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3110
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3111<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3112Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3113
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3114<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3115
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3116<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3117<pre>
3118 unwind
3119</pre>
3120
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3121<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3122<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3123 at the first callee in the dynamic call stack which used
3124 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3125 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3126
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3127<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3128<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3129 immediately halt. The dynamic call stack is then searched for the
3130 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3131 Once found, execution continues at the "exceptional" destination block
3132 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3133 instruction in the dynamic call chain, undefined behavior results.</p>
3134
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3135<p>Note that the code generator does not yet completely support unwind, and
3136that the invoke/unwind semantics are likely to change in future versions.</p>
3137
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3138</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3139
3140<!-- _______________________________________________________________________ -->
3141
3142<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3143Instruction</a> </div>
3144
3145<div class="doc_text">
3146
3147<h5>Syntax:</h5>
3148<pre>
3149 unreachable
3150</pre>
3151
3152<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3153<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3154 instruction is used to inform the optimizer that a particular portion of the
3155 code is not reachable. This can be used to indicate that the code after a
3156 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3157
3158<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3159<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3160
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3161</div>
3162
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3163<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3164<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3165
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3166<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3167
3168<p>Binary operators are used to do most of the computation in a program. They
3169 require two operands of the same type, execute an operation on them, and
3170 produce a single value. The operands might represent multiple data, as is
3171 the case with the <a href="#t_vector">vector</a> data type. The result value
3172 has the same type as its operands.</p>
3173
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3174<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3175
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3176</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3177
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3178<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3179<div class="doc_subsubsection">
3180 <a name="i_add">'<tt>add</tt>' Instruction</a>
3181</div>
3182
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3183<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3184
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3185<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3186<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3187 &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]3188 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3189 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3190 &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]3191</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3192
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3193<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3194<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3195
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3196<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3197<p>The two arguments to the '<tt>add</tt>' instruction must
3198 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3199 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3200
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3201<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3202<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3203
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3204<p>If the sum has unsigned overflow, the result returned is the mathematical
3205 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]3206
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3207<p>Because LLVM integers use a two's complement representation, this instruction
3208 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3209
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3210<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3211 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3212 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3213 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3214 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3215
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3216<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3217<pre>
3218 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3219</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3220
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3221</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3222
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3223<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3224<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3225 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3226</div>
3227
3228<div class="doc_text">
3229
3230<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3231<pre>
3232 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3233</pre>
3234
3235<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3236<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3237
3238<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3239<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3240 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3241 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3242
3243<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3244<p>The value produced is the floating point sum of the two operands.</p>
3245
3246<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3247<pre>
3248 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3249</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3250
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3251</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3252
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3253<!-- _______________________________________________________________________ -->
3254<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3255 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3256</div>
3257
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3258<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3259
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3260<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3261<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3262 &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]3263 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3264 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3265 &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]3266</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3267
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3268<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3269<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3270 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3271
3272<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3273 '<tt>neg</tt>' instruction present in most other intermediate
3274 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3275
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3276<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3277<p>The two arguments to the '<tt>sub</tt>' instruction must
3278 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3279 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3280
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3281<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3282<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3283
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3284<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3285 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3286 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3287
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3288<p>Because LLVM integers use a two's complement representation, this instruction
3289 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3290
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3291<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3292 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3293 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3294 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3295 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3296
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3297<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3298<pre>
3299 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3300 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3301</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3302
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3303</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3304
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3305<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3306<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3307 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3308</div>
3309
3310<div class="doc_text">
3311
3312<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3313<pre>
3314 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3315</pre>
3316
3317<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3318<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3319 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3320
3321<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3322 '<tt>fneg</tt>' instruction present in most other intermediate
3323 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3324
3325<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3326<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3327 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3328 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3329
3330<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3331<p>The value produced is the floating point difference of the two operands.</p>
3332
3333<h5>Example:</h5>
3334<pre>
3335 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3336 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3337</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3338
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3339</div>
3340
3341<!-- _______________________________________________________________________ -->
3342<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3343 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3344</div>
3345
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3346<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3347
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3348<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3349<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3350 &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]3351 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3352 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3353 &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]3354</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3355
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3356<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3357<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3359<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3360<p>The two arguments to the '<tt>mul</tt>' instruction must
3361 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3362 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3364<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3365<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3366
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3367<p>If the result of the multiplication has unsigned overflow, the result
3368 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3369 width of the result.</p>
3370
3371<p>Because LLVM integers use a two's complement representation, and the result
3372 is the same width as the operands, this instruction returns the correct
3373 result for both signed and unsigned integers. If a full product
3374 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3375 be sign-extended or zero-extended as appropriate to the width of the full
3376 product.</p>
3377
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3378<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3379 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3380 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3381 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3382 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3383
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3384<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3385<pre>
3386 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3387</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3388
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3389</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3390
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3391<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3392<div class="doc_subsubsection">
3393 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3394</div>
3395
3396<div class="doc_text">
3397
3398<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3399<pre>
3400 &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]3401</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3402
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3403<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3404<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3405
3406<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3407<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3408 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3409 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3410
3411<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3412<p>The value produced is the floating point product of the two operands.</p>
3413
3414<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3415<pre>
3416 &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]3417</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3418
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3419</div>
3420
3421<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3422<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3423</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3424
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3425<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3426
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3427<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3428<pre>
3429 &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]3430</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3431
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3432<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3433<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3434
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3435<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3436<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3437 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3438 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3439
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3440<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3441<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3442
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3443<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3444 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3445
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3446<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3447
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3448<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3449<pre>
3450 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3451</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3453</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3454
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3455<!-- _______________________________________________________________________ -->
3456<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3457</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3458
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3459<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3460
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3461<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3462<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3463 &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]3464 &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]3465</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3466
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3467<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3468<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3469
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3470<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3471<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3472 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3473 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3474
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3475<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3476<p>The value produced is the signed integer quotient of the two operands rounded
3477 towards zero.</p>
3478
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3479<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3480 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3481
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3482<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3483 undefined behavior; this is a rare case, but can occur, for example, by doing
3484 a 32-bit division of -2147483648 by -1.</p>
3485
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3486<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3487 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3488 be rounded or if overflow would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3489
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3490<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3491<pre>
3492 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3493</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3494
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3495</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3496
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3497<!-- _______________________________________________________________________ -->
3498<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3499Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3500
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3501<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3502
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3503<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3504<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3505 &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]3506</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3507
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508<h5>Overview:</h5>
3509<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3510
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3511<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3512<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3513 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3514 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3515
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3516<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3517<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3518
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3519<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3520<pre>
3521 &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]3522</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3523
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3524</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3525
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3526<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3527<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3528</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3529
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3530<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3531
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3532<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3533<pre>
3534 &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]3535</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3536
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3537<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3538<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3539 division of its two arguments.</p>
3540
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3541<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3542<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3543 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3544 values. Both arguments must have identical types.</p>
3545
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3546<h5>Semantics:</h5>
3547<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3548 This instruction always performs an unsigned division to get the
3549 remainder.</p>
3550
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3551<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3552 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3553
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3554<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3555
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3556<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3557<pre>
3558 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3559</pre>
3560
3561</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3562
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3563<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3564<div class="doc_subsubsection">
3565 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3566</div>
3567
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3568<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3569
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3570<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3571<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3572 &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]3573</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3574
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3575<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3576<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3577 division of its two operands. This instruction can also take
3578 <a href="#t_vector">vector</a> versions of the values in which case the
3579 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3580
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3581<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3582<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3583 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3584 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3585
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3586<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3587<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3588 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3589 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3590 a value. For more information about the difference,
3591 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3592 Math Forum</a>. For a table of how this is implemented in various languages,
3593 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3594 Wikipedia: modulo operation</a>.</p>
3595
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3596<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3597 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3598
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3599<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3600 Overflow also leads to undefined behavior; this is a rare case, but can
3601 occur, for example, by taking the remainder of a 32-bit division of
3602 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3603 lets srem be implemented using instructions that return both the result of
3604 the division and the remainder.)</p>
3605
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3606<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3607<pre>
3608 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3609</pre>
3610
3611</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3612
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3613<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3614<div class="doc_subsubsection">
3615 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3616
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3617<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3618
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3619<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3620<pre>
3621 &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]3622</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3623
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3624<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3625<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3626 its two operands.</p>
3627
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3628<h5>Arguments:</h5>
3629<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3630 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3631 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3632
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3633<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3634<p>This instruction returns the <i>remainder</i> of a division. The remainder
3635 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3636
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3637<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3638<pre>
3639 &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]3640</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3641
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3642</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3643
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3644<!-- ======================================================================= -->
3645<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3646Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3647
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3648<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649
3650<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3651 program. They are generally very efficient instructions and can commonly be
3652 strength reduced from other instructions. They require two operands of the
3653 same type, execute an operation on them, and produce a single value. The
3654 resulting value is the same type as its operands.</p>
3655
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3656</div>
3657
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3658<!-- _______________________________________________________________________ -->
3659<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3660Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3661
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3662<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3663
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3664<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3665<pre>
3666 &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]3667</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3668
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3669<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3670<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3671 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3672
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3673<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3674<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3675 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3676 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3677
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3678<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3679<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3680 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3681 is (statically or dynamically) negative or equal to or larger than the number
3682 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3683 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3684 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3685
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3686<h5>Example:</h5>
3687<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3688 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3689 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3690 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3691 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3692 &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]3693</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3694
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3695</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3696
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3697<!-- _______________________________________________________________________ -->
3698<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3699Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3700
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3701<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3702
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3703<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3704<pre>
3705 &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]3706</pre>
3707
3708<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3709<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3710 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3711
3712<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3713<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3714 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3715 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3716
3717<h5>Semantics:</h5>
3718<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3719 significant bits of the result will be filled with zero bits after the shift.
3720 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3721 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3722 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3723 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3724
3725<h5>Example:</h5>
3726<pre>
3727 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3728 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3729 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3730 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3731 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3732 &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]3733</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3734
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3735</div>
3736
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3737<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3738<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3739Instruction</a> </div>
3740<div class="doc_text">
3741
3742<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3743<pre>
3744 &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]3745</pre>
3746
3747<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3748<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3749 operand shifted to the right a specified number of bits with sign
3750 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3751
3752<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3753<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3754 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3755 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3756
3757<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3758<p>This instruction always performs an arithmetic shift right operation, The
3759 most significant bits of the result will be filled with the sign bit
3760 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3761 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3762 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3763 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3764
3765<h5>Example:</h5>
3766<pre>
3767 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3768 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3769 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3770 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3771 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3772 &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]3773</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3774
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3775</div>
3776
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3777<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3778<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3779Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3780
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3781<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3782
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3783<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3784<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3785 &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]3786</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3787
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3788<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3789<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3790 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3791
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3792<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3793<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3794 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3795 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3796
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3797<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3798<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3799
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3800<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3801 <tbody>
3802 <tr>
3803 <td>In0</td>
3804 <td>In1</td>
3805 <td>Out</td>
3806 </tr>
3807 <tr>
3808 <td>0</td>
3809 <td>0</td>
3810 <td>0</td>
3811 </tr>
3812 <tr>
3813 <td>0</td>
3814 <td>1</td>
3815 <td>0</td>
3816 </tr>
3817 <tr>
3818 <td>1</td>
3819 <td>0</td>
3820 <td>0</td>
3821 </tr>
3822 <tr>
3823 <td>1</td>
3824 <td>1</td>
3825 <td>1</td>
3826 </tr>
3827 </tbody>
3828</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3829
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3830<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3831<pre>
3832 &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]3833 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3834 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3835</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3836</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3837<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3838<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3839
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3840<div class="doc_text">
3841
3842<h5>Syntax:</h5>
3843<pre>
3844 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3845</pre>
3846
3847<h5>Overview:</h5>
3848<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3849 two operands.</p>
3850
3851<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3852<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3853 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3854 values. Both arguments must have identical types.</p>
3855
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3856<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3857<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3858
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3859<table border="1" cellspacing="0" cellpadding="4">
3860 <tbody>
3861 <tr>
3862 <td>In0</td>
3863 <td>In1</td>
3864 <td>Out</td>
3865 </tr>
3866 <tr>
3867 <td>0</td>
3868 <td>0</td>
3869 <td>0</td>
3870 </tr>
3871 <tr>
3872 <td>0</td>
3873 <td>1</td>
3874 <td>1</td>
3875 </tr>
3876 <tr>
3877 <td>1</td>
3878 <td>0</td>
3879 <td>1</td>
3880 </tr>
3881 <tr>
3882 <td>1</td>
3883 <td>1</td>
3884 <td>1</td>
3885 </tr>
3886 </tbody>
3887</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3888
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3889<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3890<pre>
3891 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3892 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3893 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3894</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3895
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3896</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3898<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3899<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3900Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3901
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3902<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3903
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3904<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3905<pre>
3906 &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]3907</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3909<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3910<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3911 its two operands. The <tt>xor</tt> is used to implement the "one's
3912 complement" operation, which is the "~" operator in C.</p>
3913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3914<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3915<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3916 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3917 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3918
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3919<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3920<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3921
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3922<table border="1" cellspacing="0" cellpadding="4">
3923 <tbody>
3924 <tr>
3925 <td>In0</td>
3926 <td>In1</td>
3927 <td>Out</td>
3928 </tr>
3929 <tr>
3930 <td>0</td>
3931 <td>0</td>
3932 <td>0</td>
3933 </tr>
3934 <tr>
3935 <td>0</td>
3936 <td>1</td>
3937 <td>1</td>
3938 </tr>
3939 <tr>
3940 <td>1</td>
3941 <td>0</td>
3942 <td>1</td>
3943 </tr>
3944 <tr>
3945 <td>1</td>
3946 <td>1</td>
3947 <td>0</td>
3948 </tr>
3949 </tbody>
3950</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3951
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3952<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3953<pre>
3954 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3955 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3956 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3957 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3958</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3959
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3960</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3961
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3962<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3963<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3964 <a name="vectorops">Vector Operations</a>
3965</div>
3966
3967<div class="doc_text">
3968
3969<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3970 target-independent manner. These instructions cover the element-access and
3971 vector-specific operations needed to process vectors effectively. While LLVM
3972 does directly support these vector operations, many sophisticated algorithms
3973 will want to use target-specific intrinsics to take full advantage of a
3974 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3975
3976</div>
3977
3978<!-- _______________________________________________________________________ -->
3979<div class="doc_subsubsection">
3980 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3981</div>
3982
3983<div class="doc_text">
3984
3985<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3986<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3987 &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]3988</pre>
3989
3990<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3991<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3992 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3993
3994
3995<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3996<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3997 of <a href="#t_vector">vector</a> type. The second operand is an index
3998 indicating the position from which to extract the element. The index may be
3999 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4000
4001<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4002<p>The result is a scalar of the same type as the element type of
4003 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4004 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4005 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4006
4007<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4008<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4009 &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]4010</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4011
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4012</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4013
4014<!-- _______________________________________________________________________ -->
4015<div class="doc_subsubsection">
4016 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4017</div>
4018
4019<div class="doc_text">
4020
4021<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4022<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4023 &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]4024</pre>
4025
4026<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4027<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4028 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4029
4030<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4031<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4032 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4033 whose type must equal the element type of the first operand. The third
4034 operand is an index indicating the position at which to insert the value.
4035 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4036
4037<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4038<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4039 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4040 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4041 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4042
4043<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4044<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4045 &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]4046</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4047
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4048</div>
4049
4050<!-- _______________________________________________________________________ -->
4051<div class="doc_subsubsection">
4052 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4053</div>
4054
4055<div class="doc_text">
4056
4057<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4058<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4059 &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]4060</pre>
4061
4062<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4063<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4064 from two input vectors, returning a vector with the same element type as the
4065 input and length that is the same as the shuffle mask.</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 two operands of a '<tt>shufflevector</tt>' instruction are vectors
4069 with types that match each other. The third argument is a shuffle mask whose
4070 element type is always 'i32'. The result of the instruction is a vector
4071 whose length is the same as the shuffle mask and whose element type is the
4072 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4073
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4074<p>The shuffle mask operand is required to be a constant vector with either
4075 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4076
4077<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4078<p>The elements of the two input vectors are numbered from left to right across
4079 both of the vectors. The shuffle mask operand specifies, for each element of
4080 the result vector, which element of the two input vectors the result element
4081 gets. The element selector may be undef (meaning "don't care") and the
4082 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4083
4084<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4085<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4086 &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]4087 &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]4088 &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]4089 &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]4090 &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]4091 &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]4092 &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]4093 &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]4094</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4095
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4096</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4097
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4098<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4099<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4100 <a name="aggregateops">Aggregate Operations</a>
4101</div>
4102
4103<div class="doc_text">
4104
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4105<p>LLVM supports several instructions for working with
4106 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4107
4108</div>
4109
4110<!-- _______________________________________________________________________ -->
4111<div class="doc_subsubsection">
4112 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4113</div>
4114
4115<div class="doc_text">
4116
4117<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4118<pre>
4119 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4120</pre>
4121
4122<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4123<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4124 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4125
4126<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4127<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4128 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4129 <a href="#t_array">array</a> type. The operands are constant indices to
4130 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4131 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4132
4133<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4134<p>The result is the value at the position in the aggregate specified by the
4135 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4136
4137<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4138<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4139 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4140</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4141
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4142</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4143
4144<!-- _______________________________________________________________________ -->
4145<div class="doc_subsubsection">
4146 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4147</div>
4148
4149<div class="doc_text">
4150
4151<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4152<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4153 &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]4154</pre>
4155
4156<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4157<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4158 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4159
4160<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4161<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4162 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4163 <a href="#t_array">array</a> type. The second operand is a first-class
4164 value to insert. The following operands are constant indices indicating
4165 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]4166 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4167 value to insert must have the same type as the value identified by the
4168 indices.</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 an aggregate of the same type as <tt>val</tt>. Its value is
4172 that of <tt>val</tt> except that the value at the position specified by the
4173 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4174
4175<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4176<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4177 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4178 %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]4179</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4180
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4181</div>
4182
4183
4184<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4185<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4186 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4187</div>
4188
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4189<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4190
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4191<p>A key design point of an SSA-based representation is how it represents
4192 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4193 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4194 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4195
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4196</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4197
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4198<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4199<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4200 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4201</div>
4202
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4203<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4204
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4205<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4206<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4207 &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]4208</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4209
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4210<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4211<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4212 currently executing function, to be automatically released when this function
4213 returns to its caller. The object is always allocated in the generic address
4214 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4215
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4216<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4217<p>The '<tt>alloca</tt>' instruction
4218 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4219 runtime stack, returning a pointer of the appropriate type to the program.
4220 If "NumElements" is specified, it is the number of elements allocated,
4221 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4222 specified, the value result of the allocation is guaranteed to be aligned to
4223 at least that boundary. If not specified, or if zero, the target can choose
4224 to align the allocation on any convenient boundary compatible with the
4225 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4226
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4227<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4228
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4229<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4230<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4231 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4232 memory is automatically released when the function returns. The
4233 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4234 variables that must have an address available. When the function returns
4235 (either with the <tt><a href="#i_ret">ret</a></tt>
4236 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4237 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4238
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4239<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4240<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4241 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4242 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4243 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4244 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4245</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4246
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4247</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4248
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4249<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4250<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4251Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4252
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4253<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4254
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4255<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4256<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4257 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4258 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4259 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4260</pre>
4261
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4262<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4263<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4264
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4265<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4266<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4267 from which to load. The pointer must point to
4268 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4269 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4270 number or order of execution of this <tt>load</tt> with other <a
4271 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4272
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4273<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4274 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]4275 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4276 alignment for the target. It is the responsibility of the code emitter to
4277 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4278 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4279 produce less efficient code. An alignment of 1 is always safe.</p>
4280
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4281<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4282 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4283 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4284 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4285 and code generator that this load is not expected to be reused in the cache.
4286 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4287 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4288
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4289<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4290<p>The location of memory pointed to is loaded. If the value being loaded is of
4291 scalar type then the number of bytes read does not exceed the minimum number
4292 of bytes needed to hold all bits of the type. For example, loading an
4293 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4294 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4295 is undefined if the value was not originally written using a store of the
4296 same type.</p>
4297
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4298<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4299<pre>
4300 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4301 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4302 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4303</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4304
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4305</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4306
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4307<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4308<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4309Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4310
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4311<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4312
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4313<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4314<pre>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4315 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4316 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]4317</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4318
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4319<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4320<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4321
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4322<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4323<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4324 and an address at which to store it. The type of the
4325 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4326 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4327 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4328 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4329 order of execution of this <tt>store</tt> with other <a
4330 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4331
4332<p>The optional constant "align" argument specifies the alignment of the
4333 operation (that is, the alignment of the memory address). A value of 0 or an
4334 omitted "align" argument means that the operation has the preferential
4335 alignment for the target. It is the responsibility of the code emitter to
4336 ensure that the alignment information is correct. Overestimating the
4337 alignment results in an undefined behavior. Underestimating the alignment may
4338 produce less efficient code. An alignment of 1 is always safe.</p>
4339
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4340<p>The optional !nontemporal metadata must reference a single metatadata
4341 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4342 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4343 instruction tells the optimizer and code generator that this load is
4344 not expected to be reused in the cache. The code generator may
4345 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4346 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4347
4348
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4349<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4350<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4351 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4352 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4353 does not exceed the minimum number of bytes needed to hold all bits of the
4354 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4355 writing a value of a type like <tt>i20</tt> with a size that is not an
4356 integral number of bytes, it is unspecified what happens to the extra bits
4357 that do not belong to the type, but they will typically be overwritten.</p>
4358
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4359<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4360<pre>
4361 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4362 store i32 3, i32* %ptr <i>; yields {void}</i>
4363 %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]4364</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4365
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4366</div>
4367
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4368<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4369<div class="doc_subsubsection">
4370 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4371</div>
4372
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4373<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4374
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4375<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4376<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4377 &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]4378 &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]4379</pre>
4380
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4381<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4382<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4383 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4384 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4385
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4386<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4387<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4388 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4389 elements of the aggregate object are indexed. The interpretation of each
4390 index is dependent on the type being indexed into. The first index always
4391 indexes the pointer value given as the first argument, the second index
4392 indexes a value of the type pointed to (not necessarily the value directly
4393 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4394 indexed into must be a pointer value, subsequent types can be arrays,
4395 vectors, structs and unions. Note that subsequent types being indexed into
4396 can never be pointers, since that would require loading the pointer before
4397 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4398
4399<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]4400 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4401 integer <b>constants</b> are allowed. When indexing into an array, pointer
4402 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]4403 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4404
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4405<p>For example, let's consider a C code fragment and how it gets compiled to
4406 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4407
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4408<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4409<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4410struct RT {
4411 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4412 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4413 char C;
4414};
4415struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4416 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4417 double Y;
4418 struct RT Z;
4419};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4420
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4421int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4422 return &amp;s[1].Z.B[5][13];
4423}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4424</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4425</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4426
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4427<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4428
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4429<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4430<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4431%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4432%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4433
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4434define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4435entry:
4436 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4437 ret i32* %reg
4438}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4439</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4440</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4441
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4442<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4443<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]4444 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4445 }</tt>' type, a structure. The second index indexes into the third element
4446 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4447 i8 }</tt>' type, another structure. The third index indexes into the second
4448 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4449 array. The two dimensions of the array are subscripted into, yielding an
4450 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4451 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4452
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4453<p>Note that it is perfectly legal to index partially through a structure,
4454 returning a pointer to an inner element. Because of this, the LLVM code for
4455 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4456
4457<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4458 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4459 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4460 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4461 %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]4462 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4463 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4464 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4465 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4466</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4467
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4468<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4469 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4470 base pointer is not an <i>in bounds</i> address of an allocated object,
4471 or if any of the addresses that would be formed by successive addition of
4472 the offsets implied by the indices to the base address with infinitely
4473 precise arithmetic are not an <i>in bounds</i> address of that allocated
4474 object. The <i>in bounds</i> addresses for an allocated object are all
4475 the addresses that point into the object, plus the address one byte past
4476 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4477
4478<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4479 the base address with silently-wrapping two's complement arithmetic, and
4480 the result value of the <tt>getelementptr</tt> may be outside the object
4481 pointed to by the base pointer. The result value may not necessarily be
4482 used to access memory though, even if it happens to point into allocated
4483 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4484 section for more information.</p>
4485
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4486<p>The getelementptr instruction is often confusing. For some more insight into
4487 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4488
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4489<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4490<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4491 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4492 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4493 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4494 %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]4495 <i>; yields i8*:eptr</i>
4496 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4497 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4498 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4499</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4500
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4501</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4502
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4503<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4504<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4505</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4506
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4507<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4508
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4509<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4510 which all take a single operand and a type. They perform various bit
4511 conversions on the operand.</p>
4512
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4513</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4514
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4515<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4516<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4517 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4518</div>
4519<div class="doc_text">
4520
4521<h5>Syntax:</h5>
4522<pre>
4523 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4524</pre>
4525
4526<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4527<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4528 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4529
4530<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4531<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4532 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4533 size and type of the result, which must be
4534 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4535 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4536 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4537
4538<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4539<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4540 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4541 source size must be larger than the destination size, <tt>trunc</tt> cannot
4542 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4543
4544<h5>Example:</h5>
4545<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4546 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4547 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4548 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4549</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4550
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4551</div>
4552
4553<!-- _______________________________________________________________________ -->
4554<div class="doc_subsubsection">
4555 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4556</div>
4557<div class="doc_text">
4558
4559<h5>Syntax:</h5>
4560<pre>
4561 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4562</pre>
4563
4564<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4565<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4566 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4567
4568
4569<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4570<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]4571 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4572 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]4573 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4574 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4575
4576<h5>Semantics:</h5>
4577<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]4578 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4579
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4580<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]4581
4582<h5>Example:</h5>
4583<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4584 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4585 %Y = zext i1 true to i32 <i>; yields i32:1</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_sext">'<tt>sext .. to</tt>' Instruction</a>
4593</div>
4594<div class="doc_text">
4595
4596<h5>Syntax:</h5>
4597<pre>
4598 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4599</pre>
4600
4601<h5>Overview:</h5>
4602<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4603
4604<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4605<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]4606 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4607 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4608 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4609 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4610
4611<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4612<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4613 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4614 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4615
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4616<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]4617
4618<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4619<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4620 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4621 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4622</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4623
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4624</div>
4625
4626<!-- _______________________________________________________________________ -->
4627<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4628 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4629</div>
4630
4631<div class="doc_text">
4632
4633<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4634<pre>
4635 &lt;result&gt; = fptrunc &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>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4640 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4641
4642<h5>Arguments:</h5>
4643<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4644 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4645 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]4646 <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]4647 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4648
4649<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4650<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4651 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4652 <a href="#t_floating">floating point</a> type. If the value cannot fit
4653 within the destination type, <tt>ty2</tt>, then the results are
4654 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4655
4656<h5>Example:</h5>
4657<pre>
4658 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4659 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4660</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4661
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4662</div>
4663
4664<!-- _______________________________________________________________________ -->
4665<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4666 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4667</div>
4668<div class="doc_text">
4669
4670<h5>Syntax:</h5>
4671<pre>
4672 &lt;result&gt; = fpext &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>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4677 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4678
4679<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4680<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4681 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4682 a <a href="#t_floating">floating point</a> type to cast it to. The source
4683 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4684
4685<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4686<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4687 <a href="#t_floating">floating point</a> type to a larger
4688 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4689 used to make a <i>no-op cast</i> because it always changes bits. Use
4690 <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]4691
4692<h5>Example:</h5>
4693<pre>
4694 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4695 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4696</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4697
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4698</div>
4699
4700<!-- _______________________________________________________________________ -->
4701<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4702 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4703</div>
4704<div class="doc_text">
4705
4706<h5>Syntax:</h5>
4707<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4708 &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]4709</pre>
4710
4711<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4712<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4713 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4714
4715<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4716<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4717 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4718 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4719 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4720 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4721
4722<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4723<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4724 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4725 towards zero) unsigned integer value. If the value cannot fit
4726 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4727
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4728<h5>Example:</h5>
4729<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4730 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4731 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4732 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]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 Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4739 <a name="i_fptosi">'<tt>fptosi .. 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 Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4745 &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]4746</pre>
4747
4748<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4749<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4750 <a href="#t_floating">floating point</a> <tt>value</tt> to
4751 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4752
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4753<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4754<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4755 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4756 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4757 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4758 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4759
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4760<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4761<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4762 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4763 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4764 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4765
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4766<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4767<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4768 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4769 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4770 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4771</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4772
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4773</div>
4774
4775<!-- _______________________________________________________________________ -->
4776<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4777 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4778</div>
4779<div class="doc_text">
4780
4781<h5>Syntax:</h5>
4782<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4783 &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]4784</pre>
4785
4786<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4787<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4788 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4789
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4790<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4791<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]4792 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4793 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4794 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4795 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4796
4797<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4798<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4799 integer quantity and converts it to the corresponding floating point
4800 value. If the value cannot fit in the floating point value, the results are
4801 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4802
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4803<h5>Example:</h5>
4804<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4805 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4806 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4807</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4808
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4809</div>
4810
4811<!-- _______________________________________________________________________ -->
4812<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4813 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4814</div>
4815<div class="doc_text">
4816
4817<h5>Syntax:</h5>
4818<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4819 &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]4820</pre>
4821
4822<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4823<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4824 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4825
4826<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4827<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]4828 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4829 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4830 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4831 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4832
4833<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4834<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4835 quantity and converts it to the corresponding floating point value. If the
4836 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4837
4838<h5>Example:</h5>
4839<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4840 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4841 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4842</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4843
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4844</div>
4845
4846<!-- _______________________________________________________________________ -->
4847<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4848 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4849</div>
4850<div class="doc_text">
4851
4852<h5>Syntax:</h5>
4853<pre>
4854 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4855</pre>
4856
4857<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4858<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4859 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4860
4861<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4862<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4863 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4864 <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]4865
4866<h5>Semantics:</h5>
4867<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4868 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4869 truncating or zero extending that value to the size of the integer type. If
4870 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4871 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4872 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4873 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4874
4875<h5>Example:</h5>
4876<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4877 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4878 %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]4879</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4880
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4881</div>
4882
4883<!-- _______________________________________________________________________ -->
4884<div class="doc_subsubsection">
4885 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4886</div>
4887<div class="doc_text">
4888
4889<h5>Syntax:</h5>
4890<pre>
4891 &lt;result&gt; = inttoptr &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>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4896 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4897
4898<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4899<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4900 value to cast, and a type to cast it to, which must be a
4901 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4902
4903<h5>Semantics:</h5>
4904<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4905 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4906 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4907 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4908 than the size of a pointer then a zero extension is done. If they are the
4909 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4910
4911<h5>Example:</h5>
4912<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4913 %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]4914 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4915 %Z = inttoptr i64 0 to i32* <i>; yields truncation 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">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4922 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4923</div>
4924<div class="doc_text">
4925
4926<h5>Syntax:</h5>
4927<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4928 &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]4929</pre>
4930
4931<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4932<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4933 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4934
4935<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4936<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4937 non-aggregate first class value, and a type to cast it to, which must also be
4938 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4939 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4940 identical. If the source type is a pointer, the destination type must also be
4941 a pointer. This instruction supports bitwise conversion of vectors to
4942 integers and to vectors of other types (as long as they have the same
4943 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4944
4945<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4946<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4947 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4948 this conversion. The conversion is done as if the <tt>value</tt> had been
4949 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4950 be converted to other pointer types with this instruction. To convert
4951 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4952 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4953
4954<h5>Example:</h5>
4955<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4956 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4957 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4958 %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]4959</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4960
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4961</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4962
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4963<!-- ======================================================================= -->
4964<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4965
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4966<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4967
4968<p>The instructions in this category are the "miscellaneous" instructions, which
4969 defy better classification.</p>
4970
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4971</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4972
4973<!-- _______________________________________________________________________ -->
4974<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4975</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4976
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4977<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4978
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4979<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4980<pre>
4981 &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]4982</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4983
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4984<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4985<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4986 boolean values based on comparison of its two integer, integer vector, or
4987 pointer operands.</p>
4988
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4989<h5>Arguments:</h5>
4990<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4991 the condition code indicating the kind of comparison to perform. It is not a
4992 value, just a keyword. The possible condition code are:</p>
4993
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4994<ol>
4995 <li><tt>eq</tt>: equal</li>
4996 <li><tt>ne</tt>: not equal </li>
4997 <li><tt>ugt</tt>: unsigned greater than</li>
4998 <li><tt>uge</tt>: unsigned greater or equal</li>
4999 <li><tt>ult</tt>: unsigned less than</li>
5000 <li><tt>ule</tt>: unsigned less or equal</li>
5001 <li><tt>sgt</tt>: signed greater than</li>
5002 <li><tt>sge</tt>: signed greater or equal</li>
5003 <li><tt>slt</tt>: signed less than</li>
5004 <li><tt>sle</tt>: signed less or equal</li>
5005</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5006
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5007<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5008 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5009 typed. They must also be identical types.</p>
5010
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5011<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5012<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5013 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5014 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]5015 result, as follows:</p>
5016
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5017<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5018 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5019 <tt>false</tt> otherwise. No sign interpretation is necessary or
5020 performed.</li>
5021
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5022 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5023 <tt>false</tt> otherwise. No sign interpretation is necessary or
5024 performed.</li>
5025
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5026 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5027 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5028
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5029 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5030 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5031 to <tt>op2</tt>.</li>
5032
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5033 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5034 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5035
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5036 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5037 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5038
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5039 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5040 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5041
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5042 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5043 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5044 to <tt>op2</tt>.</li>
5045
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5046 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5047 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5048
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5049 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5050 <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]5051</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5052
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5053<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5054 values are compared as if they were integers.</p>
5055
5056<p>If the operands are integer vectors, then they are compared element by
5057 element. The result is an <tt>i1</tt> vector with the same number of elements
5058 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5059
5060<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5061<pre>
5062 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5063 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5064 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5065 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5066 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5067 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5068</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5069
5070<p>Note that the code generator does not yet support vector types with
5071 the <tt>icmp</tt> instruction.</p>
5072
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5073</div>
5074
5075<!-- _______________________________________________________________________ -->
5076<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5077</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5078
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5079<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5081<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5082<pre>
5083 &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]5084</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5085
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5086<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5087<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5088 values based on comparison of its operands.</p>
5089
5090<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]5091(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5092
5093<p>If the operands are floating point vectors, then the result type is a vector
5094 of boolean with the same number of elements as the operands being
5095 compared.</p>
5096
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5097<h5>Arguments:</h5>
5098<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5099 the condition code indicating the kind of comparison to perform. It is not a
5100 value, just a keyword. The possible condition code are:</p>
5101
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5102<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5103 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5104 <li><tt>oeq</tt>: ordered and equal</li>
5105 <li><tt>ogt</tt>: ordered and greater than </li>
5106 <li><tt>oge</tt>: ordered and greater than or equal</li>
5107 <li><tt>olt</tt>: ordered and less than </li>
5108 <li><tt>ole</tt>: ordered and less than or equal</li>
5109 <li><tt>one</tt>: ordered and not equal</li>
5110 <li><tt>ord</tt>: ordered (no nans)</li>
5111 <li><tt>ueq</tt>: unordered or equal</li>
5112 <li><tt>ugt</tt>: unordered or greater than </li>
5113 <li><tt>uge</tt>: unordered or greater than or equal</li>
5114 <li><tt>ult</tt>: unordered or less than </li>
5115 <li><tt>ule</tt>: unordered or less than or equal</li>
5116 <li><tt>une</tt>: unordered or not equal</li>
5117 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5118 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5119</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5120
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5121<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5122 <i>unordered</i> means that either operand may be a QNAN.</p>
5123
5124<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5125 a <a href="#t_floating">floating point</a> type or
5126 a <a href="#t_vector">vector</a> of floating point type. They must have
5127 identical types.</p>
5128
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5129<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5130<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5131 according to the condition code given as <tt>cond</tt>. If the operands are
5132 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5133 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5134 follows:</p>
5135
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5136<ol>
5137 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5138
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5139 <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]5140 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5141
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5142 <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]5143 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5144
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5145 <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]5146 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5147
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5148 <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]5149 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5150
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5151 <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]5152 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5153
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5154 <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]5155 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5156
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5157 <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]5158
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5159 <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]5160 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5161
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5162 <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]5163 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5164
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5165 <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]5166 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5167
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5168 <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]5169 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5170
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5171 <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]5172 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5173
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5174 <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]5175 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5176
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5177 <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]5178
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5179 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5180</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5181
5182<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5183<pre>
5184 &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]5185 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5186 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5187 &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]5188</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5189
5190<p>Note that the code generator does not yet support vector types with
5191 the <tt>fcmp</tt> instruction.</p>
5192
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5193</div>
5194
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5195<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5196<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5197 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5198</div>
5199
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5200<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5201
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5202<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5203<pre>
5204 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5205</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5206
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5207<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5208<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5209 SSA graph representing the function.</p>
5210
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5211<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5212<p>The type of the incoming values is specified with the first type field. After
5213 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5214 one pair for each predecessor basic block of the current block. Only values
5215 of <a href="#t_firstclass">first class</a> type may be used as the value
5216 arguments to the PHI node. Only labels may be used as the label
5217 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5218
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5219<p>There must be no non-phi instructions between the start of a basic block and
5220 the PHI instructions: i.e. PHI instructions must be first in a basic
5221 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5222
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5223<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5224 occur on the edge from the corresponding predecessor block to the current
5225 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5226 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5227
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5228<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5229<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5230 specified by the pair corresponding to the predecessor basic block that
5231 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5232
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5233<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5234<pre>
5235Loop: ; Infinite loop that counts from 0 on up...
5236 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5237 %nextindvar = add i32 %indvar, 1
5238 br label %Loop
5239</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5240
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5241</div>
5242
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5243<!-- _______________________________________________________________________ -->
5244<div class="doc_subsubsection">
5245 <a name="i_select">'<tt>select</tt>' Instruction</a>
5246</div>
5247
5248<div class="doc_text">
5249
5250<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5251<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5252 &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>
5253
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5254 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5255</pre>
5256
5257<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5258<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5259 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5260
5261
5262<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5263<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5264 values indicating the condition, and two values of the
5265 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5266 vectors and the condition is a scalar, then entire vectors are selected, not
5267 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5268
5269<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5270<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5271 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5272
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5273<p>If the condition is a vector of i1, then the value arguments must be vectors
5274 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5275
5276<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5277<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5278 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5279</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5280
5281<p>Note that the code generator does not yet support conditions
5282 with vector type.</p>
5283
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5284</div>
5285
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5286<!-- _______________________________________________________________________ -->
5287<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5288 <a name="i_call">'<tt>call</tt>' Instruction</a>
5289</div>
5290
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5291<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5292
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5293<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5294<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5295 &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]5296</pre>
5297
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5298<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5299<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5300
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5301<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5302<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5303
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5304<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5305 <li>The optional "tail" marker indicates that the callee function does not
5306 access any allocas or varargs in the caller. Note that calls may be
5307 marked "tail" even if they do not occur before
5308 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5309 present, the function call is eligible for tail call optimization,
5310 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5311 optimized into a jump</a>. The code generator may optimize calls marked
5312 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5313 sibling call optimization</a> when the caller and callee have
5314 matching signatures, or 2) forced tail call optimization when the
5315 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5316 <ul>
5317 <li>Caller and callee both have the calling
5318 convention <tt>fastcc</tt>.</li>
5319 <li>The call is in tail position (ret immediately follows call and ret
5320 uses value of call or is void).</li>
5321 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5322 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5323 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5324 constraints are met.</a></li>
5325 </ul>
5326 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5327
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5328 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5329 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5330 defaults to using C calling conventions. The calling convention of the
5331 call must match the calling convention of the target function, or else the
5332 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5333
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5334 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5335 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5336 '<tt>inreg</tt>' attributes are valid here.</li>
5337
5338 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5339 type of the return value. Functions that return no value are marked
5340 <tt><a href="#t_void">void</a></tt>.</li>
5341
5342 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5343 being invoked. The argument types must match the types implied by this
5344 signature. This type can be omitted if the function is not varargs and if
5345 the function type does not return a pointer to a function.</li>
5346
5347 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5348 be invoked. In most cases, this is a direct function invocation, but
5349 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5350 to function value.</li>
5351
5352 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5353 signature argument types and parameter attributes. All arguments must be
5354 of <a href="#t_firstclass">first class</a> type. If the function
5355 signature indicates the function accepts a variable number of arguments,
5356 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5357
5358 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5359 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5360 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5361</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5362
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5363<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5364<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5365 a specified function, with its incoming arguments bound to the specified
5366 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5367 function, control flow continues with the instruction after the function
5368 call, and the return value of the function is bound to the result
5369 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5370
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5371<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5372<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5373 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5374 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5375 %X = tail call i32 @foo() <i>; yields i32</i>
5376 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5377 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5378
5379 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5380 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5381 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5382 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5383 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5384 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5385</pre>
5386
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5387<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5388standard C99 library as being the C99 library functions, and may perform
5389optimizations or generate code for them under that assumption. This is
5390something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5391freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5393</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5394
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5395<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5396<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5397 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5398</div>
5399
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5400<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5401
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5402<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5403<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5404 &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]5405</pre>
5406
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5407<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5408<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5409 the "variable argument" area of a function call. It is used to implement the
5410 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5411
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5412<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5413<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5414 argument. It returns a value of the specified argument type and increments
5415 the <tt>va_list</tt> to point to the next argument. The actual type
5416 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5417
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5418<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5419<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5420 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5421 to the next argument. For more information, see the variable argument
5422 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5423
5424<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]5425 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5426 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5427
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5428<p><tt>va_arg</tt> is an LLVM instruction instead of
5429 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5430 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5431
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5432<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5433<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5434
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5435<p>Note that the code generator does not yet fully support va_arg on many
5436 targets. Also, it does not currently support va_arg with aggregate types on
5437 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5438
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5439</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5440
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5441<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5442<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5443<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5444
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5445<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5446
5447<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5448 well known names and semantics and are required to follow certain
5449 restrictions. Overall, these intrinsics represent an extension mechanism for
5450 the LLVM language that does not require changing all of the transformations
5451 in LLVM when adding to the language (or the bitcode reader/writer, the
5452 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5453
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5454<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5455 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5456 begin with this prefix. Intrinsic functions must always be external
5457 functions: you cannot define the body of intrinsic functions. Intrinsic
5458 functions may only be used in call or invoke instructions: it is illegal to
5459 take the address of an intrinsic function. Additionally, because intrinsic
5460 functions are part of the LLVM language, it is required if any are added that
5461 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5462
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5463<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5464 family of functions that perform the same operation but on different data
5465 types. Because LLVM can represent over 8 million different integer types,
5466 overloading is used commonly to allow an intrinsic function to operate on any
5467 integer type. One or more of the argument types or the result type can be
5468 overloaded to accept any integer type. Argument types may also be defined as
5469 exactly matching a previous argument's type or the result type. This allows
5470 an intrinsic function which accepts multiple arguments, but needs all of them
5471 to be of the same type, to only be overloaded with respect to a single
5472 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5473
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5474<p>Overloaded intrinsics will have the names of its overloaded argument types
5475 encoded into its function name, each preceded by a period. Only those types
5476 which are overloaded result in a name suffix. Arguments whose type is matched
5477 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5478 can take an integer of any width and returns an integer of exactly the same
5479 integer width. This leads to a family of functions such as
5480 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5481 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5482 suffix is required. Because the argument's type is matched against the return
5483 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5484
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5485<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5486 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5487
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5488</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5489
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5490<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5491<div class="doc_subsection">
5492 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5493</div>
5494
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5495<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5496
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5497<p>Variable argument support is defined in LLVM with
5498 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5499 intrinsic functions. These functions are related to the similarly named
5500 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5501
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5502<p>All of these functions operate on arguments that use a target-specific value
5503 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5504 not define what this type is, so all transformations should be prepared to
5505 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5506
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5507<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]5508 instruction and the variable argument handling intrinsic functions are
5509 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5510
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5511<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5512<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5513define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5514 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5515 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5516 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5517 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5518
5519 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5520 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5521
5522 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5523 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5524 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5525 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5526 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5527
5528 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5529 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5530 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5531}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5532
5533declare void @llvm.va_start(i8*)
5534declare void @llvm.va_copy(i8*, i8*)
5535declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5536</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5537</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5538
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5539</div>
5540
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5541<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5542<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5543 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5544</div>
5545
5546
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5547<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5548
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5549<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5550<pre>
5551 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5552</pre>
5553
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5554<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5555<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5556 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]5557
5558<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5559<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]5560
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5561<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5562<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]5563 macro available in C. In a target-dependent way, it initializes
5564 the <tt>va_list</tt> element to which the argument points, so that the next
5565 call to <tt>va_arg</tt> will produce the first variable argument passed to
5566 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5567 need to know the last argument of the function as the compiler can figure
5568 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5569
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5570</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5571
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5572<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5573<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5574 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5575</div>
5576
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5577<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5578
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5579<h5>Syntax:</h5>
5580<pre>
5581 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5582</pre>
5583
5584<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5585<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5586 which has been initialized previously
5587 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5588 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5589
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5590<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5591<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]5592
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5593<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5594<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]5595 macro available in C. In a target-dependent way, it destroys
5596 the <tt>va_list</tt> element to which the argument points. Calls
5597 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5598 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5599 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5600
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5601</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5602
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5603<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5604<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5605 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5606</div>
5607
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5608<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5609
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5610<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5611<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5612 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5613</pre>
5614
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5615<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5616<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5617 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5618
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5619<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5620<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]5621 The second argument is a pointer to a <tt>va_list</tt> element to copy
5622 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5623
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5624<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5625<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]5626 macro available in C. In a target-dependent way, it copies the
5627 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5628 element. This intrinsic is necessary because
5629 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5630 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5631
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5632</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5633
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5634<!-- ======================================================================= -->
5635<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5636 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5637</div>
5638
5639<div class="doc_text">
5640
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5641<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5642Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5643intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5644roots on the stack</a>, as well as garbage collector implementations that
5645require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5646barriers. Front-ends for type-safe garbage collected languages should generate
5647these intrinsics to make use of the LLVM garbage collectors. For more details,
5648see <a href="GarbageCollection.html">Accurate Garbage Collection with
5649LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5650
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5651<p>The garbage collection intrinsics only operate on objects in the generic
5652 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5653
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5654</div>
5655
5656<!-- _______________________________________________________________________ -->
5657<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5658 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5659</div>
5660
5661<div class="doc_text">
5662
5663<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5664<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5665 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5666</pre>
5667
5668<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5669<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]5670 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5671
5672<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5673<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5674 root pointer. The second pointer (which must be either a constant or a
5675 global value address) contains the meta-data to be associated with the
5676 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5677
5678<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5679<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]5680 location. At compile-time, the code generator generates information to allow
5681 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5682 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5683 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5684
5685</div>
5686
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5687<!-- _______________________________________________________________________ -->
5688<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5689 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5690</div>
5691
5692<div class="doc_text">
5693
5694<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5695<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5696 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5697</pre>
5698
5699<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5700<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5701 locations, allowing garbage collector implementations that require read
5702 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5703
5704<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5705<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]5706 allocated from the garbage collector. The first object is a pointer to the
5707 start of the referenced object, if needed by the language runtime (otherwise
5708 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5709
5710<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5711<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5712 instruction, but may be replaced with substantially more complex code by the
5713 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5714 may only be used in a function which <a href="#gc">specifies a GC
5715 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5716
5717</div>
5718
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5719<!-- _______________________________________________________________________ -->
5720<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5721 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5722</div>
5723
5724<div class="doc_text">
5725
5726<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5727<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5728 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5729</pre>
5730
5731<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5732<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5733 locations, allowing garbage collector implementations that require write
5734 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5735
5736<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5737<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]5738 object to store it to, and the third is the address of the field of Obj to
5739 store to. If the runtime does not require a pointer to the object, Obj may
5740 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5741
5742<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5743<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5744 instruction, but may be replaced with substantially more complex code by the
5745 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5746 may only be used in a function which <a href="#gc">specifies a GC
5747 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5748
5749</div>
5750
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5751<!-- ======================================================================= -->
5752<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5753 <a name="int_codegen">Code Generator Intrinsics</a>
5754</div>
5755
5756<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5757
5758<p>These intrinsics are provided by LLVM to expose special features that may
5759 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5760
5761</div>
5762
5763<!-- _______________________________________________________________________ -->
5764<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5765 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5766</div>
5767
5768<div class="doc_text">
5769
5770<h5>Syntax:</h5>
5771<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5772 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5773</pre>
5774
5775<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5776<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5777 target-specific value indicating the return address of the current function
5778 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5779
5780<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5781<p>The argument to this intrinsic indicates which function to return the address
5782 for. Zero indicates the calling function, one indicates its caller, etc.
5783 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5784
5785<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5786<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5787 indicating the return address of the specified call frame, or zero if it
5788 cannot be identified. The value returned by this intrinsic is likely to be
5789 incorrect or 0 for arguments other than zero, so it should only be used for
5790 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5791
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5792<p>Note that calling this intrinsic does not prevent function inlining or other
5793 aggressive transformations, so the value returned may not be that of the
5794 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5795
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5796</div>
5797
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5798<!-- _______________________________________________________________________ -->
5799<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5800 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5801</div>
5802
5803<div class="doc_text">
5804
5805<h5>Syntax:</h5>
5806<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5807 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5808</pre>
5809
5810<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5811<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5812 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5813
5814<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5815<p>The argument to this intrinsic indicates which function to return the frame
5816 pointer for. Zero indicates the calling function, one indicates its caller,
5817 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5818
5819<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5820<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5821 indicating the frame address of the specified call frame, or zero if it
5822 cannot be identified. The value returned by this intrinsic is likely to be
5823 incorrect or 0 for arguments other than zero, so it should only be used for
5824 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5825
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5826<p>Note that calling this intrinsic does not prevent function inlining or other
5827 aggressive transformations, so the value returned may not be that of the
5828 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5829
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5830</div>
5831
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5832<!-- _______________________________________________________________________ -->
5833<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5834 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5835</div>
5836
5837<div class="doc_text">
5838
5839<h5>Syntax:</h5>
5840<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5841 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5842</pre>
5843
5844<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5845<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5846 of the function stack, for use
5847 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5848 useful for implementing language features like scoped automatic variable
5849 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5850
5851<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5852<p>This intrinsic returns a opaque pointer value that can be passed
5853 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5854 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5855 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5856 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5857 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5858 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5859
5860</div>
5861
5862<!-- _______________________________________________________________________ -->
5863<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5864 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5865</div>
5866
5867<div class="doc_text">
5868
5869<h5>Syntax:</h5>
5870<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5871 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5872</pre>
5873
5874<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5875<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5876 the function stack to the state it was in when the
5877 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5878 executed. This is useful for implementing language features like scoped
5879 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5880
5881<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5882<p>See the description
5883 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5884
5885</div>
5886
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5887<!-- _______________________________________________________________________ -->
5888<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5889 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5890</div>
5891
5892<div class="doc_text">
5893
5894<h5>Syntax:</h5>
5895<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5896 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]5897</pre>
5898
5899<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5900<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5901 insert a prefetch instruction if supported; otherwise, it is a noop.
5902 Prefetches have no effect on the behavior of the program but can change its
5903 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5904
5905<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5906<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5907 specifier determining if the fetch should be for a read (0) or write (1),
5908 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5909 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5910 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5911
5912<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5913<p>This intrinsic does not modify the behavior of the program. In particular,
5914 prefetches cannot trap and do not produce a value. On targets that support
5915 this intrinsic, the prefetch can provide hints to the processor cache for
5916 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5917
5918</div>
5919
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5920<!-- _______________________________________________________________________ -->
5921<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5922 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5923</div>
5924
5925<div class="doc_text">
5926
5927<h5>Syntax:</h5>
5928<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5929 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5930</pre>
5931
5932<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5933<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5934 Counter (PC) in a region of code to simulators and other tools. The method
5935 is target specific, but it is expected that the marker will use exported
5936 symbols to transmit the PC of the marker. The marker makes no guarantees
5937 that it will remain with any specific instruction after optimizations. It is
5938 possible that the presence of a marker will inhibit optimizations. The
5939 intended use is to be inserted after optimizations to allow correlations of
5940 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5941
5942<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5943<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5944
5945<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5946<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5947 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5948
5949</div>
5950
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5951<!-- _______________________________________________________________________ -->
5952<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5953 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5954</div>
5955
5956<div class="doc_text">
5957
5958<h5>Syntax:</h5>
5959<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5960 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5961</pre>
5962
5963<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5964<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5965 counter register (or similar low latency, high accuracy clocks) on those
5966 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5967 should map to RPCC. As the backing counters overflow quickly (on the order
5968 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5969
5970<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5971<p>When directly supported, reading the cycle counter should not modify any
5972 memory. Implementations are allowed to either return a application specific
5973 value or a system wide value. On backends without support, this is lowered
5974 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5975
5976</div>
5977
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5978<!-- ======================================================================= -->
5979<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5980 <a name="int_libc">Standard C Library Intrinsics</a>
5981</div>
5982
5983<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5984
5985<p>LLVM provides intrinsics for a few important standard C library functions.
5986 These intrinsics allow source-language front-ends to pass information about
5987 the alignment of the pointer arguments to the code generator, providing
5988 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5989
5990</div>
5991
5992<!-- _______________________________________________________________________ -->
5993<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5994 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5995</div>
5996
5997<div class="doc_text">
5998
5999<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6000<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]6001 integer bit width and for different address spaces. Not all targets support
6002 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6003
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6004<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6005 declare void @llvm.memcpy.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6006 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6007 declare void @llvm.memcpy.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6008 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6009</pre>
6010
6011<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6012<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6013 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6014
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6015<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6016 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6017 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6018
6019<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6020
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6021<p>The first argument is a pointer to the destination, the second is a pointer
6022 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6023 number of bytes to copy, the fourth argument is the alignment of the
6024 source and destination locations, and the fifth is a boolean indicating a
6025 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6026
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6027<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]6028 then the caller guarantees that both the source and destination pointers are
6029 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6030
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6031<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6032 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6033 The detailed access behavior is not very cleanly specified and it is unwise
6034 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6035
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6036<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6037
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6038<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6039 source location to the destination location, which are not allowed to
6040 overlap. It copies "len" bytes of memory over. If the argument is known to
6041 be aligned to some boundary, this can be specified as the fourth argument,
6042 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6043
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6044</div>
6045
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6046<!-- _______________________________________________________________________ -->
6047<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6048 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6049</div>
6050
6051<div class="doc_text">
6052
6053<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6054<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]6055 width and for different address space. Not all targets support all bit
6056 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6057
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6058<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6059 declare void @llvm.memmove.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6060 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6061 declare void @llvm.memmove.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6062 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6063</pre>
6064
6065<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6066<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6067 source location to the destination location. It is similar to the
6068 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6069 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6070
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6071<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6072 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6073 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6074
6075<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6076
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6077<p>The first argument is a pointer to the destination, the second is a pointer
6078 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6079 number of bytes to copy, the fourth argument is the alignment of the
6080 source and destination locations, and the fifth is a boolean indicating a
6081 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6082
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6083<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]6084 then the caller guarantees that the source and destination pointers are
6085 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6086
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6087<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6088 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6089 The detailed access behavior is not very cleanly specified and it is unwise
6090 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6091
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6092<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6093
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6094<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6095 source location to the destination location, which may overlap. It copies
6096 "len" bytes of memory over. If the argument is known to be aligned to some
6097 boundary, this can be specified as the fourth argument, otherwise it should
6098 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6099
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6100</div>
6101
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6102<!-- _______________________________________________________________________ -->
6103<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6104 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6105</div>
6106
6107<div class="doc_text">
6108
6109<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6110<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]6111 width and for different address spaces. Not all targets support all bit
6112 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6113
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6114<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6115 declare void @llvm.memset.p0i8.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6116 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6117 declare void @llvm.memset.p0i8.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6118 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6119</pre>
6120
6121<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6122<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6123 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6124
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6125<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6126 intrinsic does not return a value, takes extra alignment/volatile arguments,
6127 and the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6128
6129<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6130<p>The first argument is a pointer to the destination to fill, the second is the
6131 byte value to fill it with, the third argument is an integer argument
6132 specifying the number of bytes to fill, and the fourth argument is the known
6133 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6134
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6135<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]6136 then the caller guarantees that the destination pointer is aligned to that
6137 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6138
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6139<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6140 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6141 The detailed access behavior is not very cleanly specified and it is unwise
6142 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6143
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6144<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6145<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6146 at the destination location. If the argument is known to be aligned to some
6147 boundary, this can be specified as the fourth argument, otherwise it should
6148 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6149
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6150</div>
6151
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6152<!-- _______________________________________________________________________ -->
6153<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6154 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6155</div>
6156
6157<div class="doc_text">
6158
6159<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6160<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6161 floating point or vector of floating point type. Not all targets support all
6162 types however.</p>
6163
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6164<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6165 declare float @llvm.sqrt.f32(float %Val)
6166 declare double @llvm.sqrt.f64(double %Val)
6167 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6168 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6169 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6170</pre>
6171
6172<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6173<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6174 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6175 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6176 behavior for negative numbers other than -0.0 (which allows for better
6177 optimization, because there is no need to worry about errno being
6178 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]6179
6180<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6181<p>The argument and return value are floating point numbers of the same
6182 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6183
6184<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6185<p>This function returns the sqrt of the specified operand if it is a
6186 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6187
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6188</div>
6189
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6190<!-- _______________________________________________________________________ -->
6191<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6192 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6193</div>
6194
6195<div class="doc_text">
6196
6197<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6198<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6199 floating point or vector of floating point type. Not all targets support all
6200 types however.</p>
6201
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6202<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6203 declare float @llvm.powi.f32(float %Val, i32 %power)
6204 declare double @llvm.powi.f64(double %Val, i32 %power)
6205 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6206 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6207 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6208</pre>
6209
6210<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6211<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6212 specified (positive or negative) power. The order of evaluation of
6213 multiplications is not defined. When a vector of floating point type is
6214 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6215
6216<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6217<p>The second argument is an integer power, and the first is a value to raise to
6218 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6219
6220<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6221<p>This function returns the first value raised to the second power with an
6222 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6223
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6224</div>
6225
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6226<!-- _______________________________________________________________________ -->
6227<div class="doc_subsubsection">
6228 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6229</div>
6230
6231<div class="doc_text">
6232
6233<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6234<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6235 floating point or vector of floating point type. Not all targets support all
6236 types however.</p>
6237
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6238<pre>
6239 declare float @llvm.sin.f32(float %Val)
6240 declare double @llvm.sin.f64(double %Val)
6241 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6242 declare fp128 @llvm.sin.f128(fp128 %Val)
6243 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6244</pre>
6245
6246<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6247<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6248
6249<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6250<p>The argument and return value are floating point numbers of the same
6251 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6252
6253<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6254<p>This function returns the sine of the specified operand, returning the same
6255 values as the libm <tt>sin</tt> functions would, and handles error conditions
6256 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6257
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6258</div>
6259
6260<!-- _______________________________________________________________________ -->
6261<div class="doc_subsubsection">
6262 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6263</div>
6264
6265<div class="doc_text">
6266
6267<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6268<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6269 floating point or vector of floating point type. Not all targets support all
6270 types however.</p>
6271
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6272<pre>
6273 declare float @llvm.cos.f32(float %Val)
6274 declare double @llvm.cos.f64(double %Val)
6275 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6276 declare fp128 @llvm.cos.f128(fp128 %Val)
6277 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6278</pre>
6279
6280<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6281<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6282
6283<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6284<p>The argument and return value are floating point numbers of the same
6285 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6286
6287<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6288<p>This function returns the cosine of the specified operand, returning the same
6289 values as the libm <tt>cos</tt> functions would, and handles error conditions
6290 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6291
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6292</div>
6293
6294<!-- _______________________________________________________________________ -->
6295<div class="doc_subsubsection">
6296 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6297</div>
6298
6299<div class="doc_text">
6300
6301<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6302<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6303 floating point or vector of floating point type. Not all targets support all
6304 types however.</p>
6305
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6306<pre>
6307 declare float @llvm.pow.f32(float %Val, float %Power)
6308 declare double @llvm.pow.f64(double %Val, double %Power)
6309 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6310 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6311 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6312</pre>
6313
6314<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6315<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6316 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6317
6318<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6319<p>The second argument is a floating point power, and the first is a value to
6320 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6321
6322<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6323<p>This function returns the first value raised to the second power, returning
6324 the same values as the libm <tt>pow</tt> functions would, and handles error
6325 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6326
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6327</div>
6328
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6329<!-- ======================================================================= -->
6330<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6331 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6332</div>
6333
6334<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6335
6336<p>LLVM provides intrinsics for a few important bit manipulation operations.
6337 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6338
6339</div>
6340
6341<!-- _______________________________________________________________________ -->
6342<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6343 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6344</div>
6345
6346<div class="doc_text">
6347
6348<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6349<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6350 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6351
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6352<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6353 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6354 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6355 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6356</pre>
6357
6358<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6359<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6360 values with an even number of bytes (positive multiple of 16 bits). These
6361 are useful for performing operations on data that is not in the target's
6362 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6363
6364<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6365<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6366 and low byte of the input i16 swapped. Similarly,
6367 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6368 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6369 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6370 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6371 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6372 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6373
6374</div>
6375
6376<!-- _______________________________________________________________________ -->
6377<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6378 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6379</div>
6380
6381<div class="doc_text">
6382
6383<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6384<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]6385 width. Not all targets support all bit widths however.</p>
6386
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6387<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6388 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6389 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6390 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6391 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6392 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +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.ctpop</tt>' family of intrinsics counts the number of bits set
6397 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6398
6399<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6400<p>The only argument is the value to be counted. The argument may be of any
6401 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6402
6403<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6404<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]6405
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6406</div>
6407
6408<!-- _______________________________________________________________________ -->
6409<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6410 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6411</div>
6412
6413<div class="doc_text">
6414
6415<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6416<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6417 integer bit width. Not all targets support all bit widths however.</p>
6418
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6419<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6420 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6421 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6422 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6423 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6424 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6425</pre>
6426
6427<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6428<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6429 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6430
6431<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6432<p>The only argument is the value to be counted. The argument may be of any
6433 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6434
6435<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6436<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6437 zeros in a variable. If the src == 0 then the result is the size in bits of
6438 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6439
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6440</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6441
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6442<!-- _______________________________________________________________________ -->
6443<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6444 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6445</div>
6446
6447<div class="doc_text">
6448
6449<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6450<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6451 integer bit width. Not all targets support all bit widths however.</p>
6452
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6453<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6454 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6455 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6456 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6457 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6458 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6459</pre>
6460
6461<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6462<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6463 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6464
6465<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6466<p>The only argument is the value to be counted. The argument may be of any
6467 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6468
6469<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6470<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6471 zeros in a variable. If the src == 0 then the result is the size in bits of
6472 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6473
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6474</div>
6475
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6476<!-- ======================================================================= -->
6477<div class="doc_subsection">
6478 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6479</div>
6480
6481<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6482
6483<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6484
6485</div>
6486
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6487<!-- _______________________________________________________________________ -->
6488<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6489 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6490</div>
6491
6492<div class="doc_text">
6493
6494<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6495<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]6496 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6497
6498<pre>
6499 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6500 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6501 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6502</pre>
6503
6504<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6505<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6506 a signed addition of the two arguments, and indicate whether an overflow
6507 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6508
6509<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6510<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]6511 be of integer types of any bit width, but they must have the same bit
6512 width. The second element of the result structure must be of
6513 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6514 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6515
6516<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6517<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6518 a signed addition of the two variables. They return a structure &mdash; the
6519 first element of which is the signed summation, and the second element of
6520 which is a bit specifying if the signed summation resulted in an
6521 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6522
6523<h5>Examples:</h5>
6524<pre>
6525 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6526 %sum = extractvalue {i32, i1} %res, 0
6527 %obit = extractvalue {i32, i1} %res, 1
6528 br i1 %obit, label %overflow, label %normal
6529</pre>
6530
6531</div>
6532
6533<!-- _______________________________________________________________________ -->
6534<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6535 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6536</div>
6537
6538<div class="doc_text">
6539
6540<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6541<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]6542 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6543
6544<pre>
6545 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6546 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6547 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6548</pre>
6549
6550<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6551<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6552 an unsigned addition of the two arguments, and indicate whether a carry
6553 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6554
6555<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6556<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]6557 be of integer types of any bit width, but they must have the same bit
6558 width. The second element of the result structure must be of
6559 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6560 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6561
6562<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6563<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6564 an unsigned addition of the two arguments. They return a structure &mdash;
6565 the first element of which is the sum, and the second element of which is a
6566 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6567
6568<h5>Examples:</h5>
6569<pre>
6570 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6571 %sum = extractvalue {i32, i1} %res, 0
6572 %obit = extractvalue {i32, i1} %res, 1
6573 br i1 %obit, label %carry, label %normal
6574</pre>
6575
6576</div>
6577
6578<!-- _______________________________________________________________________ -->
6579<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6580 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6581</div>
6582
6583<div class="doc_text">
6584
6585<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6586<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]6587 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6588
6589<pre>
6590 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6591 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6592 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6593</pre>
6594
6595<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6596<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6597 a signed subtraction of the two arguments, and indicate whether an overflow
6598 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6599
6600<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6601<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]6602 be of integer types of any bit width, but they must have the same bit
6603 width. The second element of the result structure must be of
6604 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6605 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6606
6607<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6608<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6609 a signed subtraction of the two arguments. They return a structure &mdash;
6610 the first element of which is the subtraction, and the second element of
6611 which is a bit specifying if the signed subtraction resulted in an
6612 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6613
6614<h5>Examples:</h5>
6615<pre>
6616 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6617 %sum = extractvalue {i32, i1} %res, 0
6618 %obit = extractvalue {i32, i1} %res, 1
6619 br i1 %obit, label %overflow, label %normal
6620</pre>
6621
6622</div>
6623
6624<!-- _______________________________________________________________________ -->
6625<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6626 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6627</div>
6628
6629<div class="doc_text">
6630
6631<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6632<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]6633 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6634
6635<pre>
6636 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6637 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6638 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6639</pre>
6640
6641<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6642<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6643 an unsigned subtraction of the two arguments, and indicate whether an
6644 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6645
6646<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6647<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]6648 be of integer types of any bit width, but they must have the same bit
6649 width. The second element of the result structure must be of
6650 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6651 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6652
6653<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6654<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6655 an unsigned subtraction of the two arguments. They return a structure &mdash;
6656 the first element of which is the subtraction, and the second element of
6657 which is a bit specifying if the unsigned subtraction resulted in an
6658 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6659
6660<h5>Examples:</h5>
6661<pre>
6662 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6663 %sum = extractvalue {i32, i1} %res, 0
6664 %obit = extractvalue {i32, i1} %res, 1
6665 br i1 %obit, label %overflow, label %normal
6666</pre>
6667
6668</div>
6669
6670<!-- _______________________________________________________________________ -->
6671<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6672 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6673</div>
6674
6675<div class="doc_text">
6676
6677<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6678<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]6679 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6680
6681<pre>
6682 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6683 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6684 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6685</pre>
6686
6687<h5>Overview:</h5>
6688
6689<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6690 a signed multiplication of the two arguments, and indicate whether an
6691 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6692
6693<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6694<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]6695 be of integer types of any bit width, but they must have the same bit
6696 width. The second element of the result structure must be of
6697 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6698 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6699
6700<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6701<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6702 a signed multiplication of the two arguments. They return a structure &mdash;
6703 the first element of which is the multiplication, and the second element of
6704 which is a bit specifying if the signed multiplication resulted in an
6705 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6706
6707<h5>Examples:</h5>
6708<pre>
6709 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6710 %sum = extractvalue {i32, i1} %res, 0
6711 %obit = extractvalue {i32, i1} %res, 1
6712 br i1 %obit, label %overflow, label %normal
6713</pre>
6714
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6715</div>
6716
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6717<!-- _______________________________________________________________________ -->
6718<div class="doc_subsubsection">
6719 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6720</div>
6721
6722<div class="doc_text">
6723
6724<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6725<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]6726 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6727
6728<pre>
6729 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6730 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6731 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6732</pre>
6733
6734<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6735<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6736 a unsigned multiplication of the two arguments, and indicate whether an
6737 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6738
6739<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6740<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]6741 be of integer types of any bit width, but they must have the same bit
6742 width. The second element of the result structure must be of
6743 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6744 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6745
6746<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6747<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6748 an unsigned multiplication of the two arguments. They return a structure
6749 &mdash; the first element of which is the multiplication, and the second
6750 element of which is a bit specifying if the unsigned multiplication resulted
6751 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6752
6753<h5>Examples:</h5>
6754<pre>
6755 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6756 %sum = extractvalue {i32, i1} %res, 0
6757 %obit = extractvalue {i32, i1} %res, 1
6758 br i1 %obit, label %overflow, label %normal
6759</pre>
6760
6761</div>
6762
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6763<!-- ======================================================================= -->
6764<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6765 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6766</div>
6767
6768<div class="doc_text">
6769
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6770<p>Half precision floating point is a storage-only format. This means that it is
6771 a dense encoding (in memory) but does not support computation in the
6772 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6773
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6774<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6775 value as an i16, then convert it to float with <a
6776 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6777 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6778 double etc). To store the value back to memory, it is first converted to
6779 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6780 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6781 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6782</div>
6783
6784<!-- _______________________________________________________________________ -->
6785<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6786 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6787</div>
6788
6789<div class="doc_text">
6790
6791<h5>Syntax:</h5>
6792<pre>
6793 declare i16 @llvm.convert.to.fp16(f32 %a)
6794</pre>
6795
6796<h5>Overview:</h5>
6797<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6798 a conversion from single precision floating point format to half precision
6799 floating point format.</p>
6800
6801<h5>Arguments:</h5>
6802<p>The intrinsic function contains single argument - the value to be
6803 converted.</p>
6804
6805<h5>Semantics:</h5>
6806<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6807 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6808 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6809 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6810
6811<h5>Examples:</h5>
6812<pre>
6813 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6814 store i16 %res, i16* @x, align 2
6815</pre>
6816
6817</div>
6818
6819<!-- _______________________________________________________________________ -->
6820<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6821 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6822</div>
6823
6824<div class="doc_text">
6825
6826<h5>Syntax:</h5>
6827<pre>
6828 declare f32 @llvm.convert.from.fp16(i16 %a)
6829</pre>
6830
6831<h5>Overview:</h5>
6832<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6833 a conversion from half precision floating point format to single precision
6834 floating point format.</p>
6835
6836<h5>Arguments:</h5>
6837<p>The intrinsic function contains single argument - the value to be
6838 converted.</p>
6839
6840<h5>Semantics:</h5>
6841<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6842 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6843 precision floating point format. The input half-float value is represented by
6844 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6845
6846<h5>Examples:</h5>
6847<pre>
6848 %a = load i16* @x, align 2
6849 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6850</pre>
6851
6852</div>
6853
6854<!-- ======================================================================= -->
6855<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6856 <a name="int_debugger">Debugger Intrinsics</a>
6857</div>
6858
6859<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6860
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6861<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6862 prefix), are described in
6863 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6864 Level Debugging</a> document.</p>
6865
6866</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6867
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6868<!-- ======================================================================= -->
6869<div class="doc_subsection">
6870 <a name="int_eh">Exception Handling Intrinsics</a>
6871</div>
6872
6873<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6874
6875<p>The LLVM exception handling intrinsics (which all start with
6876 <tt>llvm.eh.</tt> prefix), are described in
6877 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6878 Handling</a> document.</p>
6879
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6880</div>
6881
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6882<!-- ======================================================================= -->
6883<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6884 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6885</div>
6886
6887<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6888
6889<p>This intrinsic makes it possible to excise one parameter, marked with
6890 the <tt>nest</tt> attribute, from a function. The result is a callable
6891 function pointer lacking the nest parameter - the caller does not need to
6892 provide a value for it. Instead, the value to use is stored in advance in a
6893 "trampoline", a block of memory usually allocated on the stack, which also
6894 contains code to splice the nest value into the argument list. This is used
6895 to implement the GCC nested function address extension.</p>
6896
6897<p>For example, if the function is
6898 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6899 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6900 follows:</p>
6901
6902<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6903<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6904 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6905 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6906 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6907 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6908</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6909</div>
6910
6911<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6912 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6913
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6914</div>
6915
6916<!-- _______________________________________________________________________ -->
6917<div class="doc_subsubsection">
6918 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6919</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6920
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6921<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6922
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6923<h5>Syntax:</h5>
6924<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6925 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]6926</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6927
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6928<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6929<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6930 function pointer suitable for executing it.</p>
6931
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6932<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6933<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6934 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6935 sufficiently aligned block of memory; this memory is written to by the
6936 intrinsic. Note that the size and the alignment are target-specific - LLVM
6937 currently provides no portable way of determining them, so a front-end that
6938 generates this intrinsic needs to have some target-specific knowledge.
6939 The <tt>func</tt> argument must hold a function bitcast to
6940 an <tt>i8*</tt>.</p>
6941
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6942<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6943<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6944 dependent code, turning it into a function. A pointer to this function is
6945 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6946 function pointer type</a> before being called. The new function's signature
6947 is the same as that of <tt>func</tt> with any arguments marked with
6948 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6949 is allowed, and it must be of pointer type. Calling the new function is
6950 equivalent to calling <tt>func</tt> with the same argument list, but
6951 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6952 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6953 by <tt>tramp</tt> is modified, then the effect of any later call to the
6954 returned function pointer is undefined.</p>
6955
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6956</div>
6957
6958<!-- ======================================================================= -->
6959<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6960 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6961</div>
6962
6963<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6964
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6965<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6966 hardware constructs for atomic operations and memory synchronization. This
6967 provides an interface to the hardware, not an interface to the programmer. It
6968 is aimed at a low enough level to allow any programming models or APIs
6969 (Application Programming Interfaces) which need atomic behaviors to map
6970 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6971 hardware provides a "universal IR" for source languages, it also provides a
6972 starting point for developing a "universal" atomic operation and
6973 synchronization IR.</p>
6974
6975<p>These do <em>not</em> form an API such as high-level threading libraries,
6976 software transaction memory systems, atomic primitives, and intrinsic
6977 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6978 application libraries. The hardware interface provided by LLVM should allow
6979 a clean implementation of all of these APIs and parallel programming models.
6980 No one model or paradigm should be selected above others unless the hardware
6981 itself ubiquitously does so.</p>
6982
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6983</div>
6984
6985<!-- _______________________________________________________________________ -->
6986<div class="doc_subsubsection">
6987 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6988</div>
6989<div class="doc_text">
6990<h5>Syntax:</h5>
6991<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6992 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]6993</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6994
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6995<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6996<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6997 specific pairs of memory access types.</p>
6998
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6999<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7000<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7001 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7002 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7003 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7005<ul>
7006 <li><tt>ll</tt>: load-load barrier</li>
7007 <li><tt>ls</tt>: load-store barrier</li>
7008 <li><tt>sl</tt>: store-load barrier</li>
7009 <li><tt>ss</tt>: store-store barrier</li>
7010 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7011</ul>
7012
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7013<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7014<p>This intrinsic causes the system to enforce some ordering constraints upon
7015 the loads and stores of the program. This barrier does not
7016 indicate <em>when</em> any events will occur, it only enforces
7017 an <em>order</em> in which they occur. For any of the specified pairs of load
7018 and store operations (f.ex. load-load, or store-load), all of the first
7019 operations preceding the barrier will complete before any of the second
7020 operations succeeding the barrier begin. Specifically the semantics for each
7021 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7022
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7023<ul>
7024 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7025 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7026 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7027 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7028 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7029 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7030 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7031 load after the barrier begins.</li>
7032</ul>
7033
7034<p>These semantics are applied with a logical "and" behavior when more than one
7035 is enabled in a single memory barrier intrinsic.</p>
7036
7037<p>Backends may implement stronger barriers than those requested when they do
7038 not support as fine grained a barrier as requested. Some architectures do
7039 not need all types of barriers and on such architectures, these become
7040 noops.</p>
7041
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7042<h5>Example:</h5>
7043<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7044%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7045%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7046 store i32 4, %ptr
7047
7048%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
7049 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
7050 <i>; guarantee the above finishes</i>
7051 store i32 8, %ptr <i>; before this begins</i>
7052</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7053
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7054</div>
7055
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7056<!-- _______________________________________________________________________ -->
7057<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7058 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7059</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7060
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7061<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7062
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7063<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7064<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7065 any integer bit width and for different address spaces. Not all targets
7066 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7067
7068<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7069 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
7070 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
7071 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
7072 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]7073</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7074
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7075<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7076<p>This loads a value in memory and compares it to a given value. If they are
7077 equal, it stores a new value into the memory.</p>
7078
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7079<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7080<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7081 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7082 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7083 this integer type. While any bit width integer may be used, targets may only
7084 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7085
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7086<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7087<p>This entire intrinsic must be executed atomically. It first loads the value
7088 in memory pointed to by <tt>ptr</tt> and compares it with the
7089 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7090 memory. The loaded value is yielded in all cases. This provides the
7091 equivalent of an atomic compare-and-swap operation within the SSA
7092 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7093
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7094<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7095<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7096%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7097%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7098 store i32 4, %ptr
7099
7100%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7101%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7102 <i>; yields {i32}:result1 = 4</i>
7103%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7104%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7105
7106%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7107%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7108 <i>; yields {i32}:result2 = 8</i>
7109%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7110
7111%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7112</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7113
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7114</div>
7115
7116<!-- _______________________________________________________________________ -->
7117<div class="doc_subsubsection">
7118 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7119</div>
7120<div class="doc_text">
7121<h5>Syntax:</h5>
7122
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7123<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7124 integer bit width. Not all targets support all bit widths however.</p>
7125
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7126<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7127 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
7128 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
7129 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
7130 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]7131</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7132
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7133<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7134<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7135 the value from memory. It then stores the value in <tt>val</tt> in the memory
7136 at <tt>ptr</tt>.</p>
7137
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7138<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7139<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7140 the <tt>val</tt> argument and the result must be integers of the same bit
7141 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7142 integer type. The targets may only lower integer representations they
7143 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7144
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7145<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7146<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7147 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7148 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7149
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7150<h5>Examples:</h5>
7151<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7152%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7153%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7154 store i32 4, %ptr
7155
7156%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7157%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7158 <i>; yields {i32}:result1 = 4</i>
7159%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7160%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7161
7162%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7163%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7164 <i>; yields {i32}:result2 = 8</i>
7165
7166%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7167%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7168</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7169
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7170</div>
7171
7172<!-- _______________________________________________________________________ -->
7173<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7174 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7175
7176</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7177
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7178<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7179
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7180<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7181<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7182 any integer bit width. Not all targets support all bit widths however.</p>
7183
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7184<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7185 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7186 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7187 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7188 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]7189</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7190
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7191<h5>Overview:</h5>
7192<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7193 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7194
7195<h5>Arguments:</h5>
7196<p>The intrinsic takes two arguments, the first a pointer to an integer value
7197 and the second an integer value. The result is also an integer value. These
7198 integer types can have any bit width, but they must all have the same bit
7199 width. The targets may only lower integer representations they support.</p>
7200
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7201<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7202<p>This intrinsic does a series of operations atomically. It first loads the
7203 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7204 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]7205
7206<h5>Examples:</h5>
7207<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7208%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7209%ptr = bitcast i8* %mallocP to i32*
7210 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7211%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7212 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7213%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7214 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7215%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7216 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7217%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7218</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7219
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7220</div>
7221
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7222<!-- _______________________________________________________________________ -->
7223<div class="doc_subsubsection">
7224 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7225
7226</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7227
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7228<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7229
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7230<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7231<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7232 any integer bit width and for different address spaces. Not all targets
7233 support all bit widths however.</p>
7234
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7235<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7236 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7237 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7238 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7239 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]7240</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7241
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7242<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7243<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7244 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7245
7246<h5>Arguments:</h5>
7247<p>The intrinsic takes two arguments, the first a pointer to an integer value
7248 and the second an integer value. The result is also an integer value. These
7249 integer types can have any bit width, but they must all have the same bit
7250 width. The targets may only lower integer representations they support.</p>
7251
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7252<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7253<p>This intrinsic does a series of operations atomically. It first loads the
7254 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7255 result to <tt>ptr</tt>. It yields the original value stored
7256 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7257
7258<h5>Examples:</h5>
7259<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7260%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7261%ptr = bitcast i8* %mallocP to i32*
7262 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7263%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7264 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7265%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7266 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7267%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7268 <i>; yields {i32}:result3 = 2</i>
7269%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7270</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7271
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7272</div>
7273
7274<!-- _______________________________________________________________________ -->
7275<div class="doc_subsubsection">
7276 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7277 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7278 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7279 <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]7280</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7281
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7282<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7283
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7284<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7285<p>These are overloaded intrinsics. You can
7286 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7287 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7288 bit width and for different address spaces. Not all targets support all bit
7289 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7290
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7291<pre>
7292 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7293 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7294 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7295 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]7296</pre>
7297
7298<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7299 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7300 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7301 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7302 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]7303</pre>
7304
7305<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7306 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7307 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7308 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7309 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]7310</pre>
7311
7312<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7313 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7314 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7315 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7316 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]7317</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7318
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7319<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7320<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7321 the value stored in memory at <tt>ptr</tt>. It yields the original value
7322 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7323
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7324<h5>Arguments:</h5>
7325<p>These intrinsics take two arguments, the first a pointer to an integer value
7326 and the second an integer value. The result is also an integer value. These
7327 integer types can have any bit width, but they must all have the same bit
7328 width. The targets may only lower integer representations they support.</p>
7329
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7330<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7331<p>These intrinsics does a series of operations atomically. They first load the
7332 value stored at <tt>ptr</tt>. They then do the bitwise
7333 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7334 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7335
7336<h5>Examples:</h5>
7337<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7338%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7339%ptr = bitcast i8* %mallocP to i32*
7340 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7341%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7342 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7343%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7344 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7345%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7346 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7347%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7348 <i>; yields {i32}:result3 = FF</i>
7349%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7350</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7352</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7353
7354<!-- _______________________________________________________________________ -->
7355<div class="doc_subsubsection">
7356 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7357 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7358 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7359 <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]7360</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7361
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7362<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7363
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7364<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7365<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7366 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7367 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7368 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7369
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7370<pre>
7371 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7372 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7373 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7374 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]7375</pre>
7376
7377<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7378 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7379 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7380 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7381 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]7382</pre>
7383
7384<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7385 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7386 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7387 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7388 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]7389</pre>
7390
7391<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7392 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7393 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7394 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7395 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]7396</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7397
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7398<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7399<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7400 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7401 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7402
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7403<h5>Arguments:</h5>
7404<p>These intrinsics take two arguments, the first a pointer to an integer value
7405 and the second an integer value. The result is also an integer value. These
7406 integer types can have any bit width, but they must all have the same bit
7407 width. The targets may only lower integer representations they support.</p>
7408
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7409<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7410<p>These intrinsics does a series of operations atomically. They first load the
7411 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7412 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7413 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7414
7415<h5>Examples:</h5>
7416<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7417%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7418%ptr = bitcast i8* %mallocP to i32*
7419 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7420%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7421 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7422%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7423 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7424%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7425 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7426%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7427 <i>; yields {i32}:result3 = 8</i>
7428%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7429</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7430
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7431</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7432
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7433
7434<!-- ======================================================================= -->
7435<div class="doc_subsection">
7436 <a name="int_memorymarkers">Memory Use Markers</a>
7437</div>
7438
7439<div class="doc_text">
7440
7441<p>This class of intrinsics exists to information about the lifetime of memory
7442 objects and ranges where variables are immutable.</p>
7443
7444</div>
7445
7446<!-- _______________________________________________________________________ -->
7447<div class="doc_subsubsection">
7448 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7449</div>
7450
7451<div class="doc_text">
7452
7453<h5>Syntax:</h5>
7454<pre>
7455 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7456</pre>
7457
7458<h5>Overview:</h5>
7459<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7460 object's lifetime.</p>
7461
7462<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7463<p>The first argument is a constant integer representing the size of the
7464 object, or -1 if it is variable sized. The second argument is a pointer to
7465 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7466
7467<h5>Semantics:</h5>
7468<p>This intrinsic indicates that before this point in the code, the value of the
7469 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]7470 never be used and has an undefined value. A load from the pointer that
7471 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7472 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7473
7474</div>
7475
7476<!-- _______________________________________________________________________ -->
7477<div class="doc_subsubsection">
7478 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7479</div>
7480
7481<div class="doc_text">
7482
7483<h5>Syntax:</h5>
7484<pre>
7485 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7486</pre>
7487
7488<h5>Overview:</h5>
7489<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7490 object's lifetime.</p>
7491
7492<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7493<p>The first argument is a constant integer representing the size of the
7494 object, or -1 if it is variable sized. The second argument is a pointer to
7495 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7496
7497<h5>Semantics:</h5>
7498<p>This intrinsic indicates that after this point in the code, the value of the
7499 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7500 never be used and has an undefined value. Any stores into the memory object
7501 following this intrinsic may be removed as dead.
7502
7503</div>
7504
7505<!-- _______________________________________________________________________ -->
7506<div class="doc_subsubsection">
7507 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7508</div>
7509
7510<div class="doc_text">
7511
7512<h5>Syntax:</h5>
7513<pre>
7514 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7515</pre>
7516
7517<h5>Overview:</h5>
7518<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7519 a memory object will not change.</p>
7520
7521<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7522<p>The first argument is a constant integer representing the size of the
7523 object, or -1 if it is variable sized. The second argument is a pointer to
7524 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7525
7526<h5>Semantics:</h5>
7527<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7528 the return value, the referenced memory location is constant and
7529 unchanging.</p>
7530
7531</div>
7532
7533<!-- _______________________________________________________________________ -->
7534<div class="doc_subsubsection">
7535 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7536</div>
7537
7538<div class="doc_text">
7539
7540<h5>Syntax:</h5>
7541<pre>
7542 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7543</pre>
7544
7545<h5>Overview:</h5>
7546<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7547 a memory object are mutable.</p>
7548
7549<h5>Arguments:</h5>
7550<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7551 The second argument is a constant integer representing the size of the
7552 object, or -1 if it is variable sized and the third argument is a pointer
7553 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7554
7555<h5>Semantics:</h5>
7556<p>This intrinsic indicates that the memory is mutable again.</p>
7557
7558</div>
7559
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7560<!-- ======================================================================= -->
7561<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7562 <a name="int_general">General Intrinsics</a>
7563</div>
7564
7565<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7566
7567<p>This class of intrinsics is designed to be generic and has no specific
7568 purpose.</p>
7569
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7570</div>
7571
7572<!-- _______________________________________________________________________ -->
7573<div class="doc_subsubsection">
7574 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7575</div>
7576
7577<div class="doc_text">
7578
7579<h5>Syntax:</h5>
7580<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7581 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]7582</pre>
7583
7584<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7585<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7586
7587<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7588<p>The first argument is a pointer to a value, the second is a pointer to a
7589 global string, the third is a pointer to a global string which is the source
7590 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7591
7592<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7593<p>This intrinsic allows annotation of local variables with arbitrary strings.
7594 This can be useful for special purpose optimizations that want to look for
7595 these annotations. These have no other defined use, they are ignored by code
7596 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7597
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7598</div>
7599
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7600<!-- _______________________________________________________________________ -->
7601<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7602 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7603</div>
7604
7605<div class="doc_text">
7606
7607<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7608<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7609 any integer bit width.</p>
7610
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7611<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7612 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7613 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7614 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7615 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7616 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]7617</pre>
7618
7619<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7620<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7621
7622<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7623<p>The first argument is an integer value (result of some expression), the
7624 second is a pointer to a global string, the third is a pointer to a global
7625 string which is the source file name, and the last argument is the line
7626 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7627
7628<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7629<p>This intrinsic allows annotations to be put on arbitrary expressions with
7630 arbitrary strings. This can be useful for special purpose optimizations that
7631 want to look for these annotations. These have no other defined use, they
7632 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7633
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7634</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7635
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7636<!-- _______________________________________________________________________ -->
7637<div class="doc_subsubsection">
7638 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7639</div>
7640
7641<div class="doc_text">
7642
7643<h5>Syntax:</h5>
7644<pre>
7645 declare void @llvm.trap()
7646</pre>
7647
7648<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7649<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7650
7651<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7652<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7653
7654<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7655<p>This intrinsics is lowered to the target dependent trap instruction. If the
7656 target does not have a trap instruction, this intrinsic will be lowered to
7657 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7658
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7659</div>
7660
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7661<!-- _______________________________________________________________________ -->
7662<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7663 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7664</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7665
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7666<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7667
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7668<h5>Syntax:</h5>
7669<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7670 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7671</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7672
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7673<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7674<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7675 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7676 ensure that it is placed on the stack before local variables.</p>
7677
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7678<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7679<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7680 arguments. The first argument is the value loaded from the stack
7681 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7682 that has enough space to hold the value of the guard.</p>
7683
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7684<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7685<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7686 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7687 stack. This is to ensure that if a local variable on the stack is
7688 overwritten, it will destroy the value of the guard. When the function exits,
7689 the guard on the stack is checked against the original guard. If they're
7690 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7691 function.</p>
7692
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7693</div>
7694
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7695<!-- _______________________________________________________________________ -->
7696<div class="doc_subsubsection">
7697 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7698</div>
7699
7700<div class="doc_text">
7701
7702<h5>Syntax:</h5>
7703<pre>
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7704 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7705 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7706</pre>
7707
7708<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7709<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7710 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7711 operation like memcpy will either overflow a buffer that corresponds to
7712 an object, or b) to determine that a runtime check for overflow isn't
7713 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7714 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7715
7716<h5>Arguments:</h5>
7717<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7718 argument is a pointer to or into the <tt>object</tt>. The second argument
7719 is a boolean 0 or 1. This argument determines whether you want the
7720 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7721 1, variables are not allowed.</p>
7722
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7723<h5>Semantics:</h5>
7724<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7725 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7726 (depending on the <tt>type</tt> argument if the size cannot be determined
7727 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7728
7729</div>
7730
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7731<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7732<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7733<address>
7734 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7735 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7736 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7737 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]7738
7739 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7740 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7741 Last modified: $Date$
7742</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7743
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7744</body>
7745</html>