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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 95fa80af6f0451bb52cd2d86dea1b165c5e2675a / . / 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>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]46 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]47 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]48 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]49 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]50 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]51 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]52 </ol>
53 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]54 <li><a href="#typesystem">Type System</a>
55 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]56 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]58 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]59 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_floating">Floating Point Types</a></li>
61 <li><a href="#t_void">Void Type</a></li>
62 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]63 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 </ol>
65 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]66 <li><a href="#t_derived">Derived Types</a>
67 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]68 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]69 <li><a href="#t_function">Function Type</a></li>
70 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]72 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]73 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]74 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]75 </ol>
76 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]77 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]78 </ol>
79 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]80 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]81 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]82 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]83 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]84 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
85 <li><a href="#undefvalues">Undefined Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]86 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]87 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]88 <li><a href="#metadata">Embedded Metadata</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]89 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]90 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]91 <li><a href="#othervalues">Other Values</a>
92 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]94 </ol>
95 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]96 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
97 <ol>
98 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]99 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
100 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]101 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
102 Global Variable</a></li>
103 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
104 Global Variable</a></li>
105 </ol>
106 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]107 <li><a href="#instref">Instruction Reference</a>
108 <ol>
109 <li><a href="#terminators">Terminator Instructions</a>
110 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
112 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]113 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]114 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]115 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]117 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]118 </ol>
119 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]120 <li><a href="#binaryops">Binary Operations</a>
121 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]127 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]128 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
129 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
130 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]131 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
132 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
133 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 </ol>
135 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]136 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
137 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]138 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
139 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
140 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]141 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]143 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]146 <li><a href="#vectorops">Vector Operations</a>
147 <ol>
148 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
149 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
150 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]151 </ol>
152 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]153 <li><a href="#aggregateops">Aggregate Operations</a>
154 <ol>
155 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
156 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
157 </ol>
158 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]159 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]160 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]161 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]162 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
163 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
164 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]165 </ol>
166 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]167 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]168 <ol>
169 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
170 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
171 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
172 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]174 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
175 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
176 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
177 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]178 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
179 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]180 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]181 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]182 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]183 <li><a href="#otherops">Other Operations</a>
184 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]185 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
186 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]187 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]188 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]189 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]190 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]191 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]192 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]193 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]194 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]195 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]196 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
198 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]199 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
200 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
201 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202 </ol>
203 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]204 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
205 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]206 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
207 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
208 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]209 </ol>
210 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]211 <li><a href="#int_codegen">Code Generator Intrinsics</a>
212 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]213 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
214 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
215 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
216 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
217 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
218 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
219 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]220 </ol>
221 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]222 <li><a href="#int_libc">Standard C Library Intrinsics</a>
223 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]224 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
225 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
227 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
228 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]229 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
230 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]232 </ol>
233 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]234 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]235 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]236 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]237 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
238 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
239 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]240 </ol>
241 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]242 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
243 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]244 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
245 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
246 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
247 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
248 <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]249 <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]250 </ol>
251 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]252 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]253 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]254 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]255 <ol>
256 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]257 </ol>
258 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]259 <li><a href="#int_atomics">Atomic intrinsics</a>
260 <ol>
261 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
262 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
263 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
264 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
265 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
266 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
267 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
268 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
269 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
270 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
271 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
272 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
273 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
274 </ol>
275 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]276 <li><a href="#int_memorymarkers">Memory Use Markers</a>
277 <ol>
278 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
279 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
280 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
281 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
282 </ol>
283 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]284 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]285 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]286 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]287 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]288 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]289 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]290 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]291 '<tt>llvm.trap</tt>' Intrinsic</a></li>
292 <li><a href="#int_stackprotector">
293 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]294 <li><a href="#int_objectsize">
295 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]296 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]297 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]298 </ol>
299 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]300</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]301
302<div class="doc_author">
303 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
304 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]305</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]306
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]307<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]308<div class="doc_section"> <a name="abstract">Abstract </a></div>
309<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]310
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]311<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]312
313<p>This document is a reference manual for the LLVM assembly language. LLVM is
314 a Static Single Assignment (SSA) based representation that provides type
315 safety, low-level operations, flexibility, and the capability of representing
316 'all' high-level languages cleanly. It is the common code representation
317 used throughout all phases of the LLVM compilation strategy.</p>
318
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="introduction">Introduction</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">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]326
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]327<p>The LLVM code representation is designed to be used in three different forms:
328 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
329 for fast loading by a Just-In-Time compiler), and as a human readable
330 assembly language representation. This allows LLVM to provide a powerful
331 intermediate representation for efficient compiler transformations and
332 analysis, while providing a natural means to debug and visualize the
333 transformations. The three different forms of LLVM are all equivalent. This
334 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]335
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]336<p>The LLVM representation aims to be light-weight and low-level while being
337 expressive, typed, and extensible at the same time. It aims to be a
338 "universal IR" of sorts, by being at a low enough level that high-level ideas
339 may be cleanly mapped to it (similar to how microprocessors are "universal
340 IR's", allowing many source languages to be mapped to them). By providing
341 type information, LLVM can be used as the target of optimizations: for
342 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]343 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]344 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]345
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]346</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]347
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]348<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]349<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]350
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]351<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]352
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]353<p>It is important to note that this document describes 'well formed' LLVM
354 assembly language. There is a difference between what the parser accepts and
355 what is considered 'well formed'. For example, the following instruction is
356 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]357
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]358<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]359<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]360%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]362</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]363
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]364<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
365 LLVM infrastructure provides a verification pass that may be used to verify
366 that an LLVM module is well formed. This pass is automatically run by the
367 parser after parsing input assembly and by the optimizer before it outputs
368 bitcode. The violations pointed out by the verifier pass indicate bugs in
369 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]370
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]371</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]373<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]374
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]375<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]376<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]377<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]378
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]379<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]380
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]381<p>LLVM identifiers come in two basic types: global and local. Global
382 identifiers (functions, global variables) begin with the <tt>'@'</tt>
383 character. Local identifiers (register names, types) begin with
384 the <tt>'%'</tt> character. Additionally, there are three different formats
385 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]387<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]388 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]389 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
390 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
391 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
392 other characters in their names can be surrounded with quotes. Special
393 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
394 ASCII code for the character in hexadecimal. In this way, any character
395 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]396
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]397 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]398 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]399
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]400 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]401 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]402</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]403
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]404<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]405 don't need to worry about name clashes with reserved words, and the set of
406 reserved words may be expanded in the future without penalty. Additionally,
407 unnamed identifiers allow a compiler to quickly come up with a temporary
408 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]409
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]410<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]411 languages. There are keywords for different opcodes
412 ('<tt><a href="#i_add">add</a></tt>',
413 '<tt><a href="#i_bitcast">bitcast</a></tt>',
414 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
415 ('<tt><a href="#t_void">void</a></tt>',
416 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
417 reserved words cannot conflict with variable names, because none of them
418 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]419
420<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]421 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]422
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]423<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]425<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]426<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]427%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]428</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]429</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]430
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]431<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]433<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]435%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]437</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]439<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]441<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442<pre>
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]443%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
444%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]445%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]447</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]449<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
450 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]452<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]454 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455
456 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]457 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]458
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]459 <li>Unnamed temporaries are numbered sequentially</li>
460</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]462<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]463 demonstrating instructions, we will follow an instruction with a comment that
464 defines the type and name of value produced. Comments are shown in italic
465 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]467</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]468
469<!-- *********************************************************************** -->
470<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
471<!-- *********************************************************************** -->
472
473<!-- ======================================================================= -->
474<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
475</div>
476
477<div class="doc_text">
478
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]479<p>LLVM programs are composed of "Module"s, each of which is a translation unit
480 of the input programs. Each module consists of functions, global variables,
481 and symbol table entries. Modules may be combined together with the LLVM
482 linker, which merges function (and global variable) definitions, resolves
483 forward declarations, and merges symbol table entries. Here is an example of
484 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]485
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]486<div class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]487<pre>
488<i>; Declare the string constant as a global constant.</i>
489<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]490
491<i>; External declaration of the puts function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]492<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493
494<i>; Definition of main function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]495define i32 @main() { <i>; i32()* </i>
496 <i>; Convert [13 x i8]* to i8 *...</i>
497 %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]498
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]499 <i>; Call puts function to write out the string to stdout.</i>
500 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
501 <a href="#i_ret">ret</a> i32 0<br>}<br>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]502</pre>
503</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]504
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]505<p>This example is made up of a <a href="#globalvars">global variable</a> named
506 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
507 a <a href="#functionstructure">function definition</a> for
508 "<tt>main</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]509
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]510<p>In general, a module is made up of a list of global values, where both
511 functions and global variables are global values. Global values are
512 represented by a pointer to a memory location (in this case, a pointer to an
513 array of char, and a pointer to a function), and have one of the
514 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]515
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]516</div>
517
518<!-- ======================================================================= -->
519<div class="doc_subsection">
520 <a name="linkage">Linkage Types</a>
521</div>
522
523<div class="doc_text">
524
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]525<p>All Global Variables and Functions have one of the following types of
526 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]527
528<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]529 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]530 <dd>Global values with private linkage are only directly accessible by objects
531 in the current module. In particular, linking code into a module with an
532 private global value may cause the private to be renamed as necessary to
533 avoid collisions. Because the symbol is private to the module, all
534 references can be updated. This doesn't show up in any symbol table in the
535 object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]536
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]537 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]538 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere1eaf912009-08-24 04:32:16 +0000[diff] [blame]539 removed by the linker after evaluation. Note that (unlike private
540 symbols) linker_private symbols are subject to coalescing by the linker:
541 weak symbols get merged and redefinitions are rejected. However, unlike
542 normal strong symbols, they are removed by the linker from the final
543 linked image (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]544
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]545 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]546 <dd>Similar to private, but the value shows as a local symbol
547 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
548 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]549
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]550 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]551 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]552 into the object file corresponding to the LLVM module. They exist to
553 allow inlining and other optimizations to take place given knowledge of
554 the definition of the global, which is known to be somewhere outside the
555 module. Globals with <tt>available_externally</tt> linkage are allowed to
556 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
557 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]558
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]559 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]560 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]561 the same name when linkage occurs. This can be used to implement
562 some forms of inline functions, templates, or other code which must be
563 generated in each translation unit that uses it, but where the body may
564 be overridden with a more definitive definition later. Unreferenced
565 <tt>linkonce</tt> globals are allowed to be discarded. Note that
566 <tt>linkonce</tt> linkage does not actually allow the optimizer to
567 inline the body of this function into callers because it doesn't know if
568 this definition of the function is the definitive definition within the
569 program or whether it will be overridden by a stronger definition.
570 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
571 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]572
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]573 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]574 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
575 <tt>linkonce</tt> linkage, except that unreferenced globals with
576 <tt>weak</tt> linkage may not be discarded. This is used for globals that
577 are declared "weak" in C source code.</dd>
578
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]579 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]580 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
581 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
582 global scope.
583 Symbols with "<tt>common</tt>" linkage are merged in the same way as
584 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]585 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]586 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]587 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
588 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]589
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]590
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]591 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]592 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]593 pointer to array type. When two global variables with appending linkage
594 are linked together, the two global arrays are appended together. This is
595 the LLVM, typesafe, equivalent of having the system linker append together
596 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]599 <dd>The semantics of this linkage follow the ELF object file model: the symbol
600 is weak until linked, if not linked, the symbol becomes null instead of
601 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]602
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]603 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
604 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]605 <dd>Some languages allow differing globals to be merged, such as two functions
606 with different semantics. Other languages, such as <tt>C++</tt>, ensure
607 that only equivalent globals are ever merged (the "one definition rule" -
608 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
609 and <tt>weak_odr</tt> linkage types to indicate that the global will only
610 be merged with equivalent globals. These linkage types are otherwise the
611 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]612
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]613 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]614 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]615 visible, meaning that it participates in linkage and can be used to
616 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]617</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]618
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]619<p>The next two types of linkage are targeted for Microsoft Windows platform
620 only. They are designed to support importing (exporting) symbols from (to)
621 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]622
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]623<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]624 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]625 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]626 or variable via a global pointer to a pointer that is set up by the DLL
627 exporting the symbol. On Microsoft Windows targets, the pointer name is
628 formed by combining <code>__imp_</code> and the function or variable
629 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]630
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]631 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]632 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]633 pointer to a pointer in a DLL, so that it can be referenced with the
634 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
635 name is formed by combining <code>__imp_</code> and the function or
636 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]637</dl>
638
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]639<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
640 another module defined a "<tt>.LC0</tt>" variable and was linked with this
641 one, one of the two would be renamed, preventing a collision. Since
642 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
643 declarations), they are accessible outside of the current module.</p>
644
645<p>It is illegal for a function <i>declaration</i> to have any linkage type
646 other than "externally visible", <tt>dllimport</tt>
647 or <tt>extern_weak</tt>.</p>
648
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]649<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]650 or <tt>weak_odr</tt> linkages.</p>
651
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]652</div>
653
654<!-- ======================================================================= -->
655<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]656 <a name="callingconv">Calling Conventions</a>
657</div>
658
659<div class="doc_text">
660
661<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]662 and <a href="#i_invoke">invokes</a> can all have an optional calling
663 convention specified for the call. The calling convention of any pair of
664 dynamic caller/callee must match, or the behavior of the program is
665 undefined. The following calling conventions are supported by LLVM, and more
666 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]667
668<dl>
669 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]670 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]671 specified) matches the target C calling conventions. This calling
672 convention supports varargs function calls and tolerates some mismatch in
673 the declared prototype and implemented declaration of the function (as
674 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]675
676 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]677 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]678 (e.g. by passing things in registers). This calling convention allows the
679 target to use whatever tricks it wants to produce fast code for the
680 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame^]681 (Application Binary Interface).
682 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
683 when this convention is used.</a> This calling convention does not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]684 support varargs and requires the prototype of all callees to exactly match
685 the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]686
687 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]688 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]689 as possible under the assumption that the call is not commonly executed.
690 As such, these calls often preserve all registers so that the call does
691 not break any live ranges in the caller side. This calling convention
692 does not support varargs and requires the prototype of all callees to
693 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]695 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]696 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]697 target-specific calling conventions to be used. Target specific calling
698 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]699</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]700
701<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]702 support Pascal conventions or any other well-known target-independent
703 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]704
705</div>
706
707<!-- ======================================================================= -->
708<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]709 <a name="visibility">Visibility Styles</a>
710</div>
711
712<div class="doc_text">
713
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714<p>All Global Variables and Functions have one of the following visibility
715 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]716
717<dl>
718 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]719 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]720 that the declaration is visible to other modules and, in shared libraries,
721 means that the declared entity may be overridden. On Darwin, default
722 visibility means that the declaration is visible to other modules. Default
723 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]724
725 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]726 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]727 object if they are in the same shared object. Usually, hidden visibility
728 indicates that the symbol will not be placed into the dynamic symbol
729 table, so no other module (executable or shared library) can reference it
730 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]731
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]732 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]733 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]734 the dynamic symbol table, but that references within the defining module
735 will bind to the local symbol. That is, the symbol cannot be overridden by
736 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]737</dl>
738
739</div>
740
741<!-- ======================================================================= -->
742<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]743 <a name="namedtypes">Named Types</a>
744</div>
745
746<div class="doc_text">
747
748<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]749 it easier to read the IR and make the IR more condensed (particularly when
750 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]751
752<div class="doc_code">
753<pre>
754%mytype = type { %mytype*, i32 }
755</pre>
756</div>
757
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]758<p>You may give a name to any <a href="#typesystem">type</a> except
759 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
760 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]761
762<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]763 and that you can therefore specify multiple names for the same type. This
764 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
765 uses structural typing, the name is not part of the type. When printing out
766 LLVM IR, the printer will pick <em>one name</em> to render all types of a
767 particular shape. This means that if you have code where two different
768 source types end up having the same LLVM type, that the dumper will sometimes
769 print the "wrong" or unexpected type. This is an important design point and
770 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]771
772</div>
773
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]774<!-- ======================================================================= -->
775<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]776 <a name="globalvars">Global Variables</a>
777</div>
778
779<div class="doc_text">
780
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]781<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]782 instead of run-time. Global variables may optionally be initialized, may
783 have an explicit section to be placed in, and may have an optional explicit
784 alignment specified. A variable may be defined as "thread_local", which
785 means that it will not be shared by threads (each thread will have a
786 separated copy of the variable). A variable may be defined as a global
787 "constant," which indicates that the contents of the variable
788 will <b>never</b> be modified (enabling better optimization, allowing the
789 global data to be placed in the read-only section of an executable, etc).
790 Note that variables that need runtime initialization cannot be marked
791 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]792
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]793<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
794 constant, even if the final definition of the global is not. This capability
795 can be used to enable slightly better optimization of the program, but
796 requires the language definition to guarantee that optimizations based on the
797 'constantness' are valid for the translation units that do not include the
798 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]799
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]800<p>As SSA values, global variables define pointer values that are in scope
801 (i.e. they dominate) all basic blocks in the program. Global variables
802 always define a pointer to their "content" type because they describe a
803 region of memory, and all memory objects in LLVM are accessed through
804 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]805
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]806<p>A global variable may be declared to reside in a target-specific numbered
807 address space. For targets that support them, address spaces may affect how
808 optimizations are performed and/or what target instructions are used to
809 access the variable. The default address space is zero. The address space
810 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]811
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]812<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]813 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]814
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]815<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]816 the alignment is set to zero, the alignment of the global is set by the
817 target to whatever it feels convenient. If an explicit alignment is
818 specified, the global is forced to have at least that much alignment. All
819 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]820
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]821<p>For example, the following defines a global in a numbered address space with
822 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]823
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]824<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]825<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]826@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]827</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]828</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]829
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]830</div>
831
832
833<!-- ======================================================================= -->
834<div class="doc_subsection">
835 <a name="functionstructure">Functions</a>
836</div>
837
838<div class="doc_text">
839
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]840<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
841 optional <a href="#linkage">linkage type</a>, an optional
842 <a href="#visibility">visibility style</a>, an optional
843 <a href="#callingconv">calling convention</a>, a return type, an optional
844 <a href="#paramattrs">parameter attribute</a> for the return type, a function
845 name, a (possibly empty) argument list (each with optional
846 <a href="#paramattrs">parameter attributes</a>), optional
847 <a href="#fnattrs">function attributes</a>, an optional section, an optional
848 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
849 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]850
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]851<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
852 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]853 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]854 <a href="#callingconv">calling convention</a>, a return type, an optional
855 <a href="#paramattrs">parameter attribute</a> for the return type, a function
856 name, a possibly empty list of arguments, an optional alignment, and an
857 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]858
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]859<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]860 (Control Flow Graph) for the function. Each basic block may optionally start
861 with a label (giving the basic block a symbol table entry), contains a list
862 of instructions, and ends with a <a href="#terminators">terminator</a>
863 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]864
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]865<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]866 executed on entrance to the function, and it is not allowed to have
867 predecessor basic blocks (i.e. there can not be any branches to the entry
868 block of a function). Because the block can have no predecessors, it also
869 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]870
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]871<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]872 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]873
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]874<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]875 the alignment is set to zero, the alignment of the function is set by the
876 target to whatever it feels convenient. If an explicit alignment is
877 specified, the function is forced to have at least that much alignment. All
878 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]879
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]880<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]881<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]882<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]883define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]884 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
885 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
886 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
887 [<a href="#gc">gc</a>] { ... }
888</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]889</div>
890
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]891</div>
892
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]893<!-- ======================================================================= -->
894<div class="doc_subsection">
895 <a name="aliasstructure">Aliases</a>
896</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]897
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]898<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899
900<p>Aliases act as "second name" for the aliasee value (which can be either
901 function, global variable, another alias or bitcast of global value). Aliases
902 may have an optional <a href="#linkage">linkage type</a>, and an
903 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]904
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]905<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]906<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]907<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]908@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]909</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]910</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]911
912</div>
913
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]914<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]915<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]916
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]917<div class="doc_text">
918
919<p>The return type and each parameter of a function type may have a set of
920 <i>parameter attributes</i> associated with them. Parameter attributes are
921 used to communicate additional information about the result or parameters of
922 a function. Parameter attributes are considered to be part of the function,
923 not of the function type, so functions with different parameter attributes
924 can have the same function type.</p>
925
926<p>Parameter attributes are simple keywords that follow the type specified. If
927 multiple parameter attributes are needed, they are space separated. For
928 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]929
930<div class="doc_code">
931<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]932declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]933declare i32 @atoi(i8 zeroext)
934declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]935</pre>
936</div>
937
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]938<p>Note that any attributes for the function result (<tt>nounwind</tt>,
939 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]940
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]941<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]942
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]943<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]944 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]945 <dd>This indicates to the code generator that the parameter or return value
946 should be zero-extended to a 32-bit value by the caller (for a parameter)
947 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]948
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]949 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]950 <dd>This indicates to the code generator that the parameter or return value
951 should be sign-extended to a 32-bit value by the caller (for a parameter)
952 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]953
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]954 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]955 <dd>This indicates that this parameter or return value should be treated in a
956 special target-dependent fashion during while emitting code for a function
957 call or return (usually, by putting it in a register as opposed to memory,
958 though some targets use it to distinguish between two different kinds of
959 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]960
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]961 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]962 <dd>This indicates that the pointer parameter should really be passed by value
963 to the function. The attribute implies that a hidden copy of the pointee
964 is made between the caller and the callee, so the callee is unable to
965 modify the value in the callee. This attribute is only valid on LLVM
966 pointer arguments. It is generally used to pass structs and arrays by
967 value, but is also valid on pointers to scalars. The copy is considered
968 to belong to the caller not the callee (for example,
969 <tt><a href="#readonly">readonly</a></tt> functions should not write to
970 <tt>byval</tt> parameters). This is not a valid attribute for return
971 values. The byval attribute also supports specifying an alignment with
972 the align attribute. This has a target-specific effect on the code
973 generator that usually indicates a desired alignment for the synthesized
974 stack slot.</dd>
975
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]976 <dt><tt><b>sret</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]977 <dd>This indicates that the pointer parameter specifies the address of a
978 structure that is the return value of the function in the source program.
979 This pointer must be guaranteed by the caller to be valid: loads and
980 stores to the structure may be assumed by the callee to not to trap. This
981 may only be applied to the first parameter. This is not a valid attribute
982 for return values. </dd>
983
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]984 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]985 <dd>This indicates that the pointer does not alias any global or any other
986 parameter. The caller is responsible for ensuring that this is the
987 case. On a function return value, <tt>noalias</tt> additionally indicates
988 that the pointer does not alias any other pointers visible to the
989 caller. For further details, please see the discussion of the NoAlias
990 response in
991 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
992 analysis</a>.</dd>
993
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]994 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]995 <dd>This indicates that the callee does not make any copies of the pointer
996 that outlive the callee itself. This is not a valid attribute for return
997 values.</dd>
998
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]999 <dt><tt><b>nest</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1000 <dd>This indicates that the pointer parameter can be excised using the
1001 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1002 attribute for return values.</dd>
1003</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1004
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1005</div>
1006
1007<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1008<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1009 <a name="gc">Garbage Collector Names</a>
1010</div>
1011
1012<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1013
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1014<p>Each function may specify a garbage collector name, which is simply a
1015 string:</p>
1016
1017<div class="doc_code">
1018<pre>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1019define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1020</pre>
1021</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1022
1023<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1024 collector which will cause the compiler to alter its output in order to
1025 support the named garbage collection algorithm.</p>
1026
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1027</div>
1028
1029<!-- ======================================================================= -->
1030<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1031 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1032</div>
1033
1034<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1035
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1036<p>Function attributes are set to communicate additional information about a
1037 function. Function attributes are considered to be part of the function, not
1038 of the function type, so functions with different parameter attributes can
1039 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1040
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1041<p>Function attributes are simple keywords that follow the type specified. If
1042 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1043
1044<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1045<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1046define void @f() noinline { ... }
1047define void @f() alwaysinline { ... }
1048define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1049define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1050</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1051</div>
1052
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1053<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1054 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1055 <dd>This attribute indicates that the inliner should attempt to inline this
1056 function into callers whenever possible, ignoring any active inlining size
1057 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1058
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1059 <dt><tt><b>inlinehint</b></tt></dt>
Dale Johannesende86d472009-08-26 01:08:21 +0000[diff] [blame]1060 <dd>This attribute indicates that the source code contained a hint that inlining
1061 this function is desirable (such as the "inline" keyword in C/C++). It
1062 is just a hint; it imposes no requirements on the inliner.</dd>
1063
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1064 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1065 <dd>This attribute indicates that the inliner should never inline this
1066 function in any situation. This attribute may not be used together with
1067 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1068
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1069 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1070 <dd>This attribute suggests that optimization passes and code generator passes
1071 make choices that keep the code size of this function low, and otherwise
1072 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1073
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1074 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1075 <dd>This function attribute indicates that the function never returns
1076 normally. This produces undefined behavior at runtime if the function
1077 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1078
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1079 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1080 <dd>This function attribute indicates that the function never returns with an
1081 unwind or exceptional control flow. If the function does unwind, its
1082 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1083
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1084 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1085 <dd>This attribute indicates that the function computes its result (or decides
1086 to unwind an exception) based strictly on its arguments, without
1087 dereferencing any pointer arguments or otherwise accessing any mutable
1088 state (e.g. memory, control registers, etc) visible to caller functions.
1089 It does not write through any pointer arguments
1090 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1091 changes any state visible to callers. This means that it cannot unwind
1092 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1093 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1094
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1095 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1096 <dd>This attribute indicates that the function does not write through any
1097 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1098 arguments) or otherwise modify any state (e.g. memory, control registers,
1099 etc) visible to caller functions. It may dereference pointer arguments
1100 and read state that may be set in the caller. A readonly function always
1101 returns the same value (or unwinds an exception identically) when called
1102 with the same set of arguments and global state. It cannot unwind an
1103 exception by calling the <tt>C++</tt> exception throwing methods, but may
1104 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1105
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1106 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1107 <dd>This attribute indicates that the function should emit a stack smashing
1108 protector. It is in the form of a "canary"&mdash;a random value placed on
1109 the stack before the local variables that's checked upon return from the
1110 function to see if it has been overwritten. A heuristic is used to
1111 determine if a function needs stack protectors or not.<br>
1112<br>
1113 If a function that has an <tt>ssp</tt> attribute is inlined into a
1114 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1115 function will have an <tt>ssp</tt> attribute.</dd>
1116
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1117 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1118 <dd>This attribute indicates that the function should <em>always</em> emit a
1119 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1120 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1121<br>
1122 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1123 function that doesn't have an <tt>sspreq</tt> attribute or which has
1124 an <tt>ssp</tt> attribute, then the resulting function will have
1125 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1126
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1127 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1128 <dd>This attribute indicates that the code generator should not use a red
1129 zone, even if the target-specific ABI normally permits it.</dd>
1130
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1131 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1132 <dd>This attributes disables implicit floating point instructions.</dd>
1133
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1134 <dt><tt><b>naked</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1135 <dd>This attribute disables prologue / epilogue emission for the function.
1136 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1137</dl>
1138
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1139</div>
1140
1141<!-- ======================================================================= -->
1142<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1143 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1144</div>
1145
1146<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1147
1148<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1149 the GCC "file scope inline asm" blocks. These blocks are internally
1150 concatenated by LLVM and treated as a single unit, but may be separated in
1151 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1152
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1153<div class="doc_code">
1154<pre>
1155module asm "inline asm code goes here"
1156module asm "more can go here"
1157</pre>
1158</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1159
1160<p>The strings can contain any character by escaping non-printable characters.
1161 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]1162 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1163
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1164<p>The inline asm code is simply printed to the machine code .s file when
1165 assembly code is generated.</p>
1166
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1167</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1168
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1169<!-- ======================================================================= -->
1170<div class="doc_subsection">
1171 <a name="datalayout">Data Layout</a>
1172</div>
1173
1174<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1175
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1176<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1177 data is to be laid out in memory. The syntax for the data layout is
1178 simply:</p>
1179
1180<div class="doc_code">
1181<pre>
1182target datalayout = "<i>layout specification</i>"
1183</pre>
1184</div>
1185
1186<p>The <i>layout specification</i> consists of a list of specifications
1187 separated by the minus sign character ('-'). Each specification starts with
1188 a letter and may include other information after the letter to define some
1189 aspect of the data layout. The specifications accepted are as follows:</p>
1190
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1191<dl>
1192 <dt><tt>E</tt></dt>
1193 <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]1194 bits with the most significance have the lowest address location.</dd>
1195
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1196 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1197 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1198 the bits with the least significance have the lowest address
1199 location.</dd>
1200
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1201 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1202 <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]1203 <i>preferred</i> alignments. All sizes are in bits. Specifying
1204 the <i>pref</i> alignment is optional. If omitted, the
1205 preceding <tt>:</tt> should be omitted too.</dd>
1206
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1207 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1208 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1209 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1210
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1211 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1212 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1213 <i>size</i>.</dd>
1214
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1215 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1216 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1217 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1218 (double).</dd>
1219
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1220 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1221 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1222 <i>size</i>.</dd>
1223
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1224 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1225 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1226 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1227
1228 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1229 <dd>This specifies a set of native integer widths for the target CPU
1230 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1231 "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]1232 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1233 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1234</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1235
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1236<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1237 default set of specifications which are then (possibly) overriden by the
1238 specifications in the <tt>datalayout</tt> keyword. The default specifications
1239 are given in this list:</p>
1240
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1241<ul>
1242 <li><tt>E</tt> - big endian</li>
1243 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1244 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1245 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1246 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1247 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1248 <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]1249 alignment of 64-bits</li>
1250 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1251 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1252 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1253 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1254 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1255 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1256</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1257
1258<p>When LLVM is determining the alignment for a given type, it uses the
1259 following rules:</p>
1260
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1261<ol>
1262 <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]1263 specification is used.</li>
1264
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1265 <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]1266 smallest integer type that is larger than the bitwidth of the sought type
1267 is used. If none of the specifications are larger than the bitwidth then
1268 the the largest integer type is used. For example, given the default
1269 specifications above, the i7 type will use the alignment of i8 (next
1270 largest) while both i65 and i256 will use the alignment of i64 (largest
1271 specified).</li>
1272
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1273 <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]1274 largest vector type that is smaller than the sought vector type will be
1275 used as a fall back. This happens because &lt;128 x double&gt; can be
1276 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1277</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1278
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1279</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1280
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1281<!-- ======================================================================= -->
1282<div class="doc_subsection">
1283 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1284</div>
1285
1286<div class="doc_text">
1287
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1288<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1289with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1290is undefined. Pointer values are associated with address ranges
1291according to the following rules:</p>
1292
1293<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1294 <li>A pointer value formed from a
1295 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1296 is associated with the addresses associated with the first operand
1297 of the <tt>getelementptr</tt>.</li>
1298 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1299 range of the variable's storage.</li>
1300 <li>The result value of an allocation instruction is associated with
1301 the address range of the allocated storage.</li>
1302 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1303 no address.</li>
1304 <li>A pointer value formed by an
1305 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1306 address ranges of all pointer values that contribute (directly or
1307 indirectly) to the computation of the pointer's value.</li>
1308 <li>The result value of a
1309 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1310 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1311 <li>An integer constant other than zero or a pointer value returned
1312 from a function not defined within LLVM may be associated with address
1313 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1314 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1315 allocated by mechanisms provided by LLVM.</li>
1316 </ul>
1317
1318<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1319<tt><a href="#i_load">load</a></tt> merely indicates the size and
1320alignment of the memory from which to load, as well as the
1321interpretation of the value. The first operand of a
1322<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1323and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1324
1325<p>Consequently, type-based alias analysis, aka TBAA, aka
1326<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1327LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1328additional information which specialized optimization passes may use
1329to implement type-based alias analysis.</p>
1330
1331</div>
1332
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1333<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1334<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1335<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1336
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1337<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1339<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1340 intermediate representation. Being typed enables a number of optimizations
1341 to be performed on the intermediate representation directly, without having
1342 to do extra analyses on the side before the transformation. A strong type
1343 system makes it easier to read the generated code and enables novel analyses
1344 and transformations that are not feasible to perform on normal three address
1345 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1346
1347</div>
1348
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1349<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1350<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1351Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1352
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1353<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1354
1355<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1356
1357<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1358 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1359 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1360 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1361 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1362 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1363 </tr>
1364 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1365 <td><a href="#t_floating">floating point</a></td>
1366 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1367 </tr>
1368 <tr>
1369 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1370 <td><a href="#t_integer">integer</a>,
1371 <a href="#t_floating">floating point</a>,
1372 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1373 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1374 <a href="#t_struct">structure</a>,
1375 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1376 <a href="#t_label">label</a>,
1377 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1378 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1379 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1380 <tr>
1381 <td><a href="#t_primitive">primitive</a></td>
1382 <td><a href="#t_label">label</a>,
1383 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1384 <a href="#t_floating">floating point</a>,
1385 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1386 </tr>
1387 <tr>
1388 <td><a href="#t_derived">derived</a></td>
1389 <td><a href="#t_integer">integer</a>,
1390 <a href="#t_array">array</a>,
1391 <a href="#t_function">function</a>,
1392 <a href="#t_pointer">pointer</a>,
1393 <a href="#t_struct">structure</a>,
1394 <a href="#t_pstruct">packed structure</a>,
1395 <a href="#t_vector">vector</a>,
1396 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1397 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1398 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1399 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1400</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1401
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1402<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1403 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1404 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1405
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1406</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1407
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1408<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1409<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1410
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1411<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1412
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1413<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1414 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1415
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1416</div>
1417
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1418<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1419<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1420
1421<div class="doc_text">
1422
1423<h5>Overview:</h5>
1424<p>The integer type is a very simple type that simply specifies an arbitrary
1425 bit width for the integer type desired. Any bit width from 1 bit to
1426 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1427
1428<h5>Syntax:</h5>
1429<pre>
1430 iN
1431</pre>
1432
1433<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1434 value.</p>
1435
1436<h5>Examples:</h5>
1437<table class="layout">
1438 <tr class="layout">
1439 <td class="left"><tt>i1</tt></td>
1440 <td class="left">a single-bit integer.</td>
1441 </tr>
1442 <tr class="layout">
1443 <td class="left"><tt>i32</tt></td>
1444 <td class="left">a 32-bit integer.</td>
1445 </tr>
1446 <tr class="layout">
1447 <td class="left"><tt>i1942652</tt></td>
1448 <td class="left">a really big integer of over 1 million bits.</td>
1449 </tr>
1450</table>
1451
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1452</div>
1453
1454<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1455<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1456
1457<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1458
1459<table>
1460 <tbody>
1461 <tr><th>Type</th><th>Description</th></tr>
1462 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1463 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1464 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1465 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1466 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1467 </tbody>
1468</table>
1469
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1470</div>
1471
1472<!-- _______________________________________________________________________ -->
1473<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1474
1475<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1476
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1477<h5>Overview:</h5>
1478<p>The void type does not represent any value and has no size.</p>
1479
1480<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1481<pre>
1482 void
1483</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1484
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1485</div>
1486
1487<!-- _______________________________________________________________________ -->
1488<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1489
1490<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1491
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1492<h5>Overview:</h5>
1493<p>The label type represents code labels.</p>
1494
1495<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1496<pre>
1497 label
1498</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1499
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1500</div>
1501
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1502<!-- _______________________________________________________________________ -->
1503<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1504
1505<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1506
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1507<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1508<p>The metadata type represents embedded metadata. No derived types may be
1509 created from metadata except for <a href="#t_function">function</a>
1510 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1511
1512<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1513<pre>
1514 metadata
1515</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1516
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1517</div>
1518
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1519
1520<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1521<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1522
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1523<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1524
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1525<p>The real power in LLVM comes from the derived types in the system. This is
1526 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1527 useful types. Each of these types contain one or more element types which
1528 may be a primitive type, or another derived type. For example, it is
1529 possible to have a two dimensional array, using an array as the element type
1530 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1531
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1532</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1533
1534<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1535<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1536
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1537<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1538
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1539<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1540<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1541 sequentially in memory. The array type requires a size (number of elements)
1542 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1543
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1544<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1545<pre>
1546 [&lt;# elements&gt; x &lt;elementtype&gt;]
1547</pre>
1548
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1549<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1550 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1551
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1552<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1553<table class="layout">
1554 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1555 <td class="left"><tt>[40 x i32]</tt></td>
1556 <td class="left">Array of 40 32-bit integer values.</td>
1557 </tr>
1558 <tr class="layout">
1559 <td class="left"><tt>[41 x i32]</tt></td>
1560 <td class="left">Array of 41 32-bit integer values.</td>
1561 </tr>
1562 <tr class="layout">
1563 <td class="left"><tt>[4 x i8]</tt></td>
1564 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1565 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1566</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1567<p>Here are some examples of multidimensional arrays:</p>
1568<table class="layout">
1569 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1570 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1571 <td class="left">3x4 array of 32-bit integer values.</td>
1572 </tr>
1573 <tr class="layout">
1574 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1575 <td class="left">12x10 array of single precision floating point values.</td>
1576 </tr>
1577 <tr class="layout">
1578 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1579 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1580 </tr>
1581</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1582
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1583<p>There is no restriction on indexing beyond the end of the array implied by
1584 a static type (though there are restrictions on indexing beyond the bounds
1585 of an allocated object in some cases). This means that single-dimension
1586 'variable sized array' addressing can be implemented in LLVM with a zero
1587 length array type. An implementation of 'pascal style arrays' in LLVM could
1588 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1589
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1590</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1591
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1592<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1593<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1594
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1595<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1596
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1597<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1598<p>The function type can be thought of as a function signature. It consists of
1599 a return type and a list of formal parameter types. The return type of a
1600 function type is a scalar type, a void type, or a struct type. If the return
1601 type is a struct type then all struct elements must be of first class types,
1602 and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1603
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1604<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1605<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1606 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1607</pre>
1608
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1609<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]1610 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1611 which indicates that the function takes a variable number of arguments.
1612 Variable argument functions can access their arguments with
1613 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1614 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1615 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1616
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1617<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1618<table class="layout">
1619 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1620 <td class="left"><tt>i32 (i32)</tt></td>
1621 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1622 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1623 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1624 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1625 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1626 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1627 an <tt>i16</tt> that should be sign extended and a
1628 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1629 <tt>float</tt>.
1630 </td>
1631 </tr><tr class="layout">
1632 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1633 <td class="left">A vararg function that takes at least one
1634 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1635 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1636 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1637 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1638 </tr><tr class="layout">
1639 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1640 <td class="left">A function taking an <tt>i32</tt>, returning a
1641 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1642 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1643 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1644</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1645
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1646</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1647
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1648<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1649<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1650
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1651<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1652
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1653<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1654<p>The structure type is used to represent a collection of data members together
1655 in memory. The packing of the field types is defined to match the ABI of the
1656 underlying processor. The elements of a structure may be any type that has a
1657 size.</p>
1658
1659<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1660 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1661 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1662
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1663<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1664<pre>
1665 { &lt;type list&gt; }
1666</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1667
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1668<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1669<table class="layout">
1670 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1671 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1672 <td class="left">A triple of three <tt>i32</tt> values</td>
1673 </tr><tr class="layout">
1674 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1675 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1676 second element is a <a href="#t_pointer">pointer</a> to a
1677 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1678 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1679 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1680</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1681
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1682</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1683
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1684<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1685<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1686</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1687
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1688<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1689
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1690<h5>Overview:</h5>
1691<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1692 together in memory. There is no padding between fields. Further, the
1693 alignment of a packed structure is 1 byte. The elements of a packed
1694 structure may be any type that has a size.</p>
1695
1696<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1697 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1698 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1699
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1700<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1701<pre>
1702 &lt; { &lt;type list&gt; } &gt;
1703</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1704
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1705<h5>Examples:</h5>
1706<table class="layout">
1707 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1708 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1709 <td class="left">A triple of three <tt>i32</tt> values</td>
1710 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1711 <td class="left">
1712<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1713 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1714 second element is a <a href="#t_pointer">pointer</a> to a
1715 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1716 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1717 </tr>
1718</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1719
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1720</div>
1721
1722<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1723<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1724
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1725<div class="doc_text">
1726
1727<h5>Overview:</h5>
1728<p>As in many languages, the pointer type represents a pointer or reference to
1729 another object, which must live in memory. Pointer types may have an optional
1730 address space attribute defining the target-specific numbered address space
1731 where the pointed-to object resides. The default address space is zero.</p>
1732
1733<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1734 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1735
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1736<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1737<pre>
1738 &lt;type&gt; *
1739</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1740
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1741<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1742<table class="layout">
1743 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1744 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1745 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1746 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1747 </tr>
1748 <tr class="layout">
1749 <td class="left"><tt>i32 (i32 *) *</tt></td>
1750 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1751 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1752 <tt>i32</tt>.</td>
1753 </tr>
1754 <tr class="layout">
1755 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1756 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1757 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1758 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1759</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1760
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1761</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1762
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1763<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1764<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1765
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1766<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1767
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1768<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1769<p>A vector type is a simple derived type that represents a vector of elements.
1770 Vector types are used when multiple primitive data are operated in parallel
1771 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1772 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1773 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1774
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1775<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1776<pre>
1777 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1778</pre>
1779
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1780<p>The number of elements is a constant integer value; elementtype may be any
1781 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1782
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1783<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1784<table class="layout">
1785 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1786 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1787 <td class="left">Vector of 4 32-bit integer values.</td>
1788 </tr>
1789 <tr class="layout">
1790 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1791 <td class="left">Vector of 8 32-bit floating-point values.</td>
1792 </tr>
1793 <tr class="layout">
1794 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1795 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1796 </tr>
1797</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1798
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1799</div>
1800
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1801<!-- _______________________________________________________________________ -->
1802<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1803<div class="doc_text">
1804
1805<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1806<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1807 corresponds (for example) to the C notion of a forward declared structure
1808 type. In LLVM, opaque types can eventually be resolved to any type (not just
1809 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1810
1811<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1812<pre>
1813 opaque
1814</pre>
1815
1816<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1817<table class="layout">
1818 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1819 <td class="left"><tt>opaque</tt></td>
1820 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1821 </tr>
1822</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1823
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1824</div>
1825
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1826<!-- ======================================================================= -->
1827<div class="doc_subsection">
1828 <a name="t_uprefs">Type Up-references</a>
1829</div>
1830
1831<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1832
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1833<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1834<p>An "up reference" allows you to refer to a lexically enclosing type without
1835 requiring it to have a name. For instance, a structure declaration may
1836 contain a pointer to any of the types it is lexically a member of. Example
1837 of up references (with their equivalent as named type declarations)
1838 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1839
1840<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1841 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1842 { \2 }* %y = type { %y }*
1843 \1* %z = type %z*
1844</pre>
1845
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1846<p>An up reference is needed by the asmprinter for printing out cyclic types
1847 when there is no declared name for a type in the cycle. Because the
1848 asmprinter does not want to print out an infinite type string, it needs a
1849 syntax to handle recursive types that have no names (all names are optional
1850 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1851
1852<h5>Syntax:</h5>
1853<pre>
1854 \&lt;level&gt;
1855</pre>
1856
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1857<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]1858
1859<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1860<table class="layout">
1861 <tr class="layout">
1862 <td class="left"><tt>\1*</tt></td>
1863 <td class="left">Self-referential pointer.</td>
1864 </tr>
1865 <tr class="layout">
1866 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1867 <td class="left">Recursive structure where the upref refers to the out-most
1868 structure.</td>
1869 </tr>
1870</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1871
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1872</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1873
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1874<!-- *********************************************************************** -->
1875<div class="doc_section"> <a name="constants">Constants</a> </div>
1876<!-- *********************************************************************** -->
1877
1878<div class="doc_text">
1879
1880<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1881 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1882
1883</div>
1884
1885<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1886<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1887
1888<div class="doc_text">
1889
1890<dl>
1891 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1892 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1893 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1894
1895 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1896 <dd>Standard integers (such as '4') are constants of
1897 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1898 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1899
1900 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1901 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1902 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1903 notation (see below). The assembler requires the exact decimal value of a
1904 floating-point constant. For example, the assembler accepts 1.25 but
1905 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1906 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1907
1908 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1909 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1910 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1911</dl>
1912
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1913<p>The one non-intuitive notation for constants is the hexadecimal form of
1914 floating point constants. For example, the form '<tt>double
1915 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1916 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1917 constants are required (and the only time that they are generated by the
1918 disassembler) is when a floating point constant must be emitted but it cannot
1919 be represented as a decimal floating point number in a reasonable number of
1920 digits. For example, NaN's, infinities, and other special values are
1921 represented in their IEEE hexadecimal format so that assembly and disassembly
1922 do not cause any bits to change in the constants.</p>
1923
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]1924<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1925 represented using the 16-digit form shown above (which matches the IEEE754
1926 representation for double); float values must, however, be exactly
1927 representable as IEE754 single precision. Hexadecimal format is always used
1928 for long double, and there are three forms of long double. The 80-bit format
1929 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1930 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1931 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1932 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1933 currently supported target uses this format. Long doubles will only work if
1934 they match the long double format on your target. All hexadecimal formats
1935 are big-endian (sign bit at the left).</p>
1936
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1937</div>
1938
1939<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1940<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]1941<a name="aggregateconstants"></a> <!-- old anchor -->
1942<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1943</div>
1944
1945<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1946
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1947<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1948 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1949
1950<dl>
1951 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1952 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1953 type definitions (a comma separated list of elements, surrounded by braces
1954 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1955 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1956 Structure constants must have <a href="#t_struct">structure type</a>, and
1957 the number and types of elements must match those specified by the
1958 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1959
1960 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1961 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1962 definitions (a comma separated list of elements, surrounded by square
1963 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1964 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1965 the number and types of elements must match those specified by the
1966 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1967
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1968 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1969 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1970 definitions (a comma separated list of elements, surrounded by
1971 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1972 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1973 have <a href="#t_vector">vector type</a>, and the number and types of
1974 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1975
1976 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1977 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1978 value to zero of <em>any</em> type, including scalar and aggregate types.
1979 This is often used to avoid having to print large zero initializers
1980 (e.g. for large arrays) and is always exactly equivalent to using explicit
1981 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]1982
1983 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]1984 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1985 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1986 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1987 be interpreted as part of the instruction stream, metadata is a place to
1988 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1989</dl>
1990
1991</div>
1992
1993<!-- ======================================================================= -->
1994<div class="doc_subsection">
1995 <a name="globalconstants">Global Variable and Function Addresses</a>
1996</div>
1997
1998<div class="doc_text">
1999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2000<p>The addresses of <a href="#globalvars">global variables</a>
2001 and <a href="#functionstructure">functions</a> are always implicitly valid
2002 (link-time) constants. These constants are explicitly referenced when
2003 the <a href="#identifiers">identifier for the global</a> is used and always
2004 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2005 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2006
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2007<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2008<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2009@X = global i32 17
2010@Y = global i32 42
2011@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2012</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2013</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2014
2015</div>
2016
2017<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2018<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2019<div class="doc_text">
2020
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2021<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]2022 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2023 Undefined values may be of any type (other than label or void) and be used
2024 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2025
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2026<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2027 program is well defined no matter what value is used. This gives the
2028 compiler more freedom to optimize. Here are some examples of (potentially
2029 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2030
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2031
2032<div class="doc_code">
2033<pre>
2034 %A = add %X, undef
2035 %B = sub %X, undef
2036 %C = xor %X, undef
2037Safe:
2038 %A = undef
2039 %B = undef
2040 %C = undef
2041</pre>
2042</div>
2043
2044<p>This is safe because all of the output bits are affected by the undef bits.
2045Any output bit can have a zero or one depending on the input bits.</p>
2046
2047<div class="doc_code">
2048<pre>
2049 %A = or %X, undef
2050 %B = and %X, undef
2051Safe:
2052 %A = -1
2053 %B = 0
2054Unsafe:
2055 %A = undef
2056 %B = undef
2057</pre>
2058</div>
2059
2060<p>These logical operations have bits that are not always affected by the input.
2061For example, if "%X" has a zero bit, then the output of the 'and' operation will
2062always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2063such, 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]2064However, it is safe to assume that all bits of the undef could be 0, and
2065optimize the and to 0. Likewise, it is safe to assume that all the bits of
2066the 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]2067-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2068
2069<div class="doc_code">
2070<pre>
2071 %A = select undef, %X, %Y
2072 %B = select undef, 42, %Y
2073 %C = select %X, %Y, undef
2074Safe:
2075 %A = %X (or %Y)
2076 %B = 42 (or %Y)
2077 %C = %Y
2078Unsafe:
2079 %A = undef
2080 %B = undef
2081 %C = undef
2082</pre>
2083</div>
2084
2085<p>This set of examples show that undefined select (and conditional branch)
2086conditions can go "either way" but they have to come from one of the two
2087operands. In the %A example, if %X and %Y were both known to have a clear low
2088bit, then %A would have to have a cleared low bit. However, in the %C example,
2089the optimizer is allowed to assume that the undef operand could be the same as
2090%Y, allowing the whole select to be eliminated.</p>
2091
2092
2093<div class="doc_code">
2094<pre>
2095 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2096
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2097 %B = undef
2098 %C = xor %B, %B
2099
2100 %D = undef
2101 %E = icmp lt %D, 4
2102 %F = icmp gte %D, 4
2103
2104Safe:
2105 %A = undef
2106 %B = undef
2107 %C = undef
2108 %D = undef
2109 %E = undef
2110 %F = undef
2111</pre>
2112</div>
2113
2114<p>This example points out that two undef operands are not necessarily the same.
2115This can be surprising to people (and also matches C semantics) where they
2116assume that "X^X" is always zero, even if X is undef. This isn't true for a
2117number of reasons, but the short answer is that an undef "variable" can
2118arbitrarily change its value over its "live range". This is true because the
2119"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2120logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2121so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2122to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2123would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2124
2125<div class="doc_code">
2126<pre>
2127 %A = fdiv undef, %X
2128 %B = fdiv %X, undef
2129Safe:
2130 %A = undef
2131b: unreachable
2132</pre>
2133</div>
2134
2135<p>These examples show the crucial difference between an <em>undefined
2136value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2137allowed to have an arbitrary bit-pattern. This means that the %A operation
2138can be constant folded to undef because the undef could be an SNaN, and fdiv is
2139not (currently) defined on SNaN's. However, in the second example, we can make
2140a more aggressive assumption: because the undef is allowed to be an arbitrary
2141value, 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]2142has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2143does not execute at all. This allows us to delete the divide and all code after
2144it: since the undefined operation "can't happen", the optimizer can assume that
2145it occurs in dead code.
2146</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2147
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2148<div class="doc_code">
2149<pre>
2150a: store undef -> %X
2151b: store %X -> undef
2152Safe:
2153a: &lt;deleted&gt;
2154b: unreachable
2155</pre>
2156</div>
2157
2158<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2159can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2160overwritten with bits that happen to match what was already there. However, a
2161store "to" an undefined location could clobber arbitrary memory, therefore, it
2162has undefined behavior.</p>
2163
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2164</div>
2165
2166<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2167<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2168 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2169<div class="doc_text">
2170
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2171<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2172
2173<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2174 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2175 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2176
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2177<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2178 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2179 against null. Pointer equality tests between labels addresses is undefined
2180 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2181 equal to the null pointer. This may also be passed around as an opaque
2182 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2183 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2184 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2185
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2186<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2187 using the value as the operand to an inline assembly, but that is target
2188 specific.
2189 </p>
2190
2191</div>
2192
2193
2194<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2195<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2196</div>
2197
2198<div class="doc_text">
2199
2200<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2201 to be used as constants. Constant expressions may be of
2202 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2203 operation that does not have side effects (e.g. load and call are not
2204 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2205
2206<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2207 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2208 <dd>Truncate a constant to another type. The bit size of CST must be larger
2209 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2210
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2211 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2212 <dd>Zero extend a constant to another type. The bit size of CST must be
2213 smaller or equal to the bit size of TYPE. Both types must be
2214 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2215
2216 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2217 <dd>Sign extend a constant to another type. The bit size of CST must be
2218 smaller or equal to the bit size of TYPE. Both types must be
2219 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2220
2221 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2222 <dd>Truncate a floating point constant to another floating point type. The
2223 size of CST must be larger than the size of TYPE. Both types must be
2224 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2225
2226 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2227 <dd>Floating point extend a constant to another type. The size of CST must be
2228 smaller or equal to the size of TYPE. Both types must be floating
2229 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2230
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2231 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2232 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2233 constant. TYPE must be a scalar or vector integer type. CST must be of
2234 scalar or vector floating point type. Both CST and TYPE must be scalars,
2235 or vectors of the same number of elements. If the value won't fit in the
2236 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2237
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2238 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2239 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2240 constant. TYPE must be a scalar or vector integer type. CST must be of
2241 scalar or vector floating point type. Both CST and TYPE must be scalars,
2242 or vectors of the same number of elements. If the value won't fit in the
2243 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2244
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2245 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2246 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2247 constant. TYPE must be a scalar or vector floating point type. CST must be
2248 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2249 vectors of the same number of elements. If the value won't fit in the
2250 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2251
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2252 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2253 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2254 constant. TYPE must be a scalar or vector floating point type. CST must be
2255 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2256 vectors of the same number of elements. If the value won't fit in the
2257 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2258
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2259 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2260 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2261 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2262 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2263 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2264
2265 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2266 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2267 type. CST must be of integer type. The CST value is zero extended,
2268 truncated, or unchanged to make it fit in a pointer size. This one is
2269 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2270
2271 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2272 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2273 are the same as those for the <a href="#i_bitcast">bitcast
2274 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2275
2276 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2277 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2278 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2279 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2280 instruction, the index list may have zero or more indexes, which are
2281 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2282
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2283 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2284 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2285
2286 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2287 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2288
2289 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2290 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2291
2292 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2293 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2294 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2295
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2296 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2297 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2298 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2299
2300 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2301 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2302 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2303
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2304 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2305 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2306 be any of the <a href="#binaryops">binary</a>
2307 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2308 on operands are the same as those for the corresponding instruction
2309 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2310</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2311
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2312</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2313
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2314<!-- ======================================================================= -->
2315<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2316</div>
2317
2318<div class="doc_text">
2319
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2320<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2321 stream without affecting the behaviour of the program. There are two
2322 metadata primitives, strings and nodes. All metadata has the
2323 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2324 point ('<tt>!</tt>').</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2325
2326<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2327 any character by escaping non-printable characters with "\xx" where "xx" is
2328 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2329
2330<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2331 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2332 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2333 10}</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2334
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2335<p>A metadata node will attempt to track changes to the values it holds. In the
2336 event that a value is deleted, it will be replaced with a typeless
2337 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckycb337992009-05-10 20:57:05 +0000[diff] [blame]2338
Devang Patel3e30c2a2010-01-05 20:41:31 +0000[diff] [blame]2339<p>A named metadata is a collection of metadata nodes. For example: "<tt>!foo =
2340 metadata !{!4, !3}</tt>".
2341
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2342<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2343 the program that isn't available in the instructions, or that isn't easily
2344 computable. Similarly, the code generator may expect a certain metadata
2345 format to be used to express debugging information.</p>
2346
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2347</div>
2348
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2349<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2350<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2351<!-- *********************************************************************** -->
2352
2353<!-- ======================================================================= -->
2354<div class="doc_subsection">
2355<a name="inlineasm">Inline Assembler Expressions</a>
2356</div>
2357
2358<div class="doc_text">
2359
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2360<p>LLVM supports inline assembler expressions (as opposed
2361 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2362 a special value. This value represents the inline assembler as a string
2363 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2364 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2365 expression has side effects, and a flag indicating whether the function
2366 containing the asm needs to align its stack conservatively. An example
2367 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2368
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2369<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2370<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2371i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2372</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2373</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2374
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2375<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2376 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2377 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2378
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2379<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2380<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2381%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]2382</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2383</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2384
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2385<p>Inline asms with side effects not visible in the constraint list must be
2386 marked as having side effects. This is done through the use of the
2387 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2388
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2389<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2390<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2391call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2392</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2393</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2394
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2395<p>In some cases inline asms will contain code that will not work unless the
2396 stack is aligned in some way, such as calls or SSE instructions on x86,
2397 yet will not contain code that does that alignment within the asm.
2398 The compiler should make conservative assumptions about what the asm might
2399 contain and should generate its usual stack alignment code in the prologue
2400 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2401
2402<div class="doc_code">
2403<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2404call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2405</pre>
2406</div>
2407
2408<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2409 first.</p>
2410
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2411<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2412 documented here. Constraints on what can be done (e.g. duplication, moving,
2413 etc need to be documented). This is probably best done by reference to
2414 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2415
2416</div>
2417
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2418
2419<!-- *********************************************************************** -->
2420<div class="doc_section">
2421 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2422</div>
2423<!-- *********************************************************************** -->
2424
2425<p>LLVM has a number of "magic" global variables that contain data that affect
2426code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2427of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2428section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2429by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2430
2431<!-- ======================================================================= -->
2432<div class="doc_subsection">
2433<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2434</div>
2435
2436<div class="doc_text">
2437
2438<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2439href="#linkage_appending">appending linkage</a>. This array contains a list of
2440pointers to global variables and functions which may optionally have a pointer
2441cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2442
2443<pre>
2444 @X = global i8 4
2445 @Y = global i32 123
2446
2447 @llvm.used = appending global [2 x i8*] [
2448 i8* @X,
2449 i8* bitcast (i32* @Y to i8*)
2450 ], section "llvm.metadata"
2451</pre>
2452
2453<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2454compiler, assembler, and linker are required to treat the symbol as if there is
2455a reference to the global that it cannot see. For example, if a variable has
2456internal linkage and no references other than that from the <tt>@llvm.used</tt>
2457list, it cannot be deleted. This is commonly used to represent references from
2458inline asms and other things the compiler cannot "see", and corresponds to
2459"attribute((used))" in GNU C.</p>
2460
2461<p>On some targets, the code generator must emit a directive to the assembler or
2462object file to prevent the assembler and linker from molesting the symbol.</p>
2463
2464</div>
2465
2466<!-- ======================================================================= -->
2467<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2468<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2469</div>
2470
2471<div class="doc_text">
2472
2473<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2474<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2475touching the symbol. On targets that support it, this allows an intelligent
2476linker to optimize references to the symbol without being impeded as it would be
2477by <tt>@llvm.used</tt>.</p>
2478
2479<p>This is a rare construct that should only be used in rare circumstances, and
2480should not be exposed to source languages.</p>
2481
2482</div>
2483
2484<!-- ======================================================================= -->
2485<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2486<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2487</div>
2488
2489<div class="doc_text">
2490
2491<p>TODO: Describe this.</p>
2492
2493</div>
2494
2495<!-- ======================================================================= -->
2496<div class="doc_subsection">
2497<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2498</div>
2499
2500<div class="doc_text">
2501
2502<p>TODO: Describe this.</p>
2503
2504</div>
2505
2506
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2507<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2508<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2509<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2510
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2511<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2512
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2513<p>The LLVM instruction set consists of several different classifications of
2514 instructions: <a href="#terminators">terminator
2515 instructions</a>, <a href="#binaryops">binary instructions</a>,
2516 <a href="#bitwiseops">bitwise binary instructions</a>,
2517 <a href="#memoryops">memory instructions</a>, and
2518 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2519
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2520</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2521
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2522<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2523<div class="doc_subsection"> <a name="terminators">Terminator
2524Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2525
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2526<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2527
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2528<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2529 in a program ends with a "Terminator" instruction, which indicates which
2530 block should be executed after the current block is finished. These
2531 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2532 control flow, not values (the one exception being the
2533 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2534
2535<p>There are six different terminator instructions: the
2536 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2537 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2538 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2539 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2540 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2541 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2542 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2543
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2544</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2545
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2546<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2547<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2548Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2549
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2550<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2551
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2552<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2553<pre>
2554 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]2555 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2556</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2557
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2558<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2559<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2560 a value) from a function back to the caller.</p>
2561
2562<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2563 value and then causes control flow, and one that just causes control flow to
2564 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2565
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2566<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2567<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2568 return value. The type of the return value must be a
2569 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2570
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2571<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2572 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2573 value or a return value with a type that does not match its type, or if it
2574 has a void return type and contains a '<tt>ret</tt>' instruction with a
2575 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2576
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2577<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2578<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2579 the calling function's context. If the caller is a
2580 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2581 instruction after the call. If the caller was an
2582 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2583 the beginning of the "normal" destination block. If the instruction returns
2584 a value, that value shall set the call or invoke instruction's return
2585 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2587<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2588<pre>
2589 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2590 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2591 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]2592</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2593
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2594</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2595<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2596<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2597
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2598<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2599
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2600<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2601<pre>
2602 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]2603</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2604
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2605<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2606<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2607 different basic block in the current function. There are two forms of this
2608 instruction, corresponding to a conditional branch and an unconditional
2609 branch.</p>
2610
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2611<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2612<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2613 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2614 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2615 target.</p>
2616
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2617<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2618<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2619 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2620 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2621 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2622
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2623<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2624<pre>
2625Test:
2626 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2627 br i1 %cond, label %IfEqual, label %IfUnequal
2628IfEqual:
2629 <a href="#i_ret">ret</a> i32 1
2630IfUnequal:
2631 <a href="#i_ret">ret</a> i32 0
2632</pre>
2633
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2634</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2635
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2636<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2637<div class="doc_subsubsection">
2638 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2639</div>
2640
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2641<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2642
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2643<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2644<pre>
2645 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2646</pre>
2647
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2648<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2649<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]2650 several different places. It is a generalization of the '<tt>br</tt>'
2651 instruction, allowing a branch to occur to one of many possible
2652 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2653
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2654<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2655<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2656 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2657 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2658 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2659
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2660<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2661<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2662 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2663 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2664 transferred to the corresponding destination; otherwise, control flow is
2665 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2666
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2667<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2668<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2669 <tt>switch</tt> instruction, this instruction may be code generated in
2670 different ways. For example, it could be generated as a series of chained
2671 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2672
2673<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2674<pre>
2675 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2676 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2677 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2678
2679 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2680 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2681
2682 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2683 switch i32 %val, label %otherwise [ i32 0, label %onzero
2684 i32 1, label %onone
2685 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2686</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2687
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2688</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2689
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2690
2691<!-- _______________________________________________________________________ -->
2692<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2693 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2694</div>
2695
2696<div class="doc_text">
2697
2698<h5>Syntax:</h5>
2699<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2700 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]2701</pre>
2702
2703<h5>Overview:</h5>
2704
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2705<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2706 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2707 "<tt>address</tt>". Address must be derived from a <a
2708 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2709
2710<h5>Arguments:</h5>
2711
2712<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2713 rest of the arguments indicate the full set of possible destinations that the
2714 address may point to. Blocks are allowed to occur multiple times in the
2715 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2716
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2717<p>This destination list is required so that dataflow analysis has an accurate
2718 understanding of the CFG.</p>
2719
2720<h5>Semantics:</h5>
2721
2722<p>Control transfers to the block specified in the address argument. All
2723 possible destination blocks must be listed in the label list, otherwise this
2724 instruction has undefined behavior. This implies that jumps to labels
2725 defined in other functions have undefined behavior as well.</p>
2726
2727<h5>Implementation:</h5>
2728
2729<p>This is typically implemented with a jump through a register.</p>
2730
2731<h5>Example:</h5>
2732<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2733 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2734</pre>
2735
2736</div>
2737
2738
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2739<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2740<div class="doc_subsubsection">
2741 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2742</div>
2743
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2744<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2745
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2746<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2747<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2748 &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]2749 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2750</pre>
2751
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2752<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2753<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2754 function, with the possibility of control flow transfer to either the
2755 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2756 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2757 control flow will return to the "normal" label. If the callee (or any
2758 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2759 instruction, control is interrupted and continued at the dynamically nearest
2760 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2761
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2762<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2763<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2764
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2765<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2766 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2767 convention</a> the call should use. If none is specified, the call
2768 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2769
2770 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2771 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2772 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2773
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2774 <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]2775 function value being invoked. In most cases, this is a direct function
2776 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2777 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2778
2779 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2780 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2781
2782 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2783 signature argument types. If the function signature indicates the
2784 function accepts a variable number of arguments, the extra arguments can
2785 be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2786
2787 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2788 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2789
2790 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2791 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2792
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2793 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2794 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2795 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2796</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2797
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2798<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2799<p>This instruction is designed to operate as a standard
2800 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2801 primary difference is that it establishes an association with a label, which
2802 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2803
2804<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2805 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2806 exception. Additionally, this is important for implementation of
2807 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2808
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2809<p>For the purposes of the SSA form, the definition of the value returned by the
2810 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2811 block to the "normal" label. If the callee unwinds then no return value is
2812 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]2813
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2814<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2815<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2816 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2817 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2818 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2819 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2820</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2821
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2822</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2823
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2824<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2825
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2826<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2827Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2828
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2829<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2830
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2831<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2832<pre>
2833 unwind
2834</pre>
2835
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2836<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2837<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2838 at the first callee in the dynamic call stack which used
2839 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2840 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2841
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2842<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2843<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2844 immediately halt. The dynamic call stack is then searched for the
2845 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2846 Once found, execution continues at the "exceptional" destination block
2847 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2848 instruction in the dynamic call chain, undefined behavior results.</p>
2849
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2850</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2851
2852<!-- _______________________________________________________________________ -->
2853
2854<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2855Instruction</a> </div>
2856
2857<div class="doc_text">
2858
2859<h5>Syntax:</h5>
2860<pre>
2861 unreachable
2862</pre>
2863
2864<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2865<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2866 instruction is used to inform the optimizer that a particular portion of the
2867 code is not reachable. This can be used to indicate that the code after a
2868 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2869
2870<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2871<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2872
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2873</div>
2874
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2875<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2876<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2877
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2878<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2879
2880<p>Binary operators are used to do most of the computation in a program. They
2881 require two operands of the same type, execute an operation on them, and
2882 produce a single value. The operands might represent multiple data, as is
2883 the case with the <a href="#t_vector">vector</a> data type. The result value
2884 has the same type as its operands.</p>
2885
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2886<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2887
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2888</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2889
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2890<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2891<div class="doc_subsubsection">
2892 <a name="i_add">'<tt>add</tt>' Instruction</a>
2893</div>
2894
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2895<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2896
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2897<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2898<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2899 &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]2900 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2901 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2902 &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]2903</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2904
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2905<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2906<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2907
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2908<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2909<p>The two arguments to the '<tt>add</tt>' instruction must
2910 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2911 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2912
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2913<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2914<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2915
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2916<p>If the sum has unsigned overflow, the result returned is the mathematical
2917 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]2918
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2919<p>Because LLVM integers use a two's complement representation, this instruction
2920 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2921
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2922<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2923 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2924 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2925 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2926
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2927<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2928<pre>
2929 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2930</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2931
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2932</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2933
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2934<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2935<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2936 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2937</div>
2938
2939<div class="doc_text">
2940
2941<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2942<pre>
2943 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2944</pre>
2945
2946<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2947<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2948
2949<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2950<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2951 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2952 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2953
2954<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2955<p>The value produced is the floating point sum of the two operands.</p>
2956
2957<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2958<pre>
2959 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2960</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2961
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2962</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2963
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2964<!-- _______________________________________________________________________ -->
2965<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2966 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2967</div>
2968
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2969<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2970
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2971<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2972<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2973 &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]2974 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2975 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2976 &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]2977</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2978
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2979<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2980<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2981 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2982
2983<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2984 '<tt>neg</tt>' instruction present in most other intermediate
2985 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2986
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2987<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2988<p>The two arguments to the '<tt>sub</tt>' instruction must
2989 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2990 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2991
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2992<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2993<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2994
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2995<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2996 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2997 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2998
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2999<p>Because LLVM integers use a two's complement representation, this instruction
3000 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3001
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3002<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3003 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3004 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3005 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3007<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3008<pre>
3009 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3010 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3011</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3012
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3013</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3014
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3015<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3016<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3017 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3018</div>
3019
3020<div class="doc_text">
3021
3022<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3023<pre>
3024 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3025</pre>
3026
3027<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3028<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3029 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3030
3031<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3032 '<tt>fneg</tt>' instruction present in most other intermediate
3033 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3034
3035<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3036<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3037 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3038 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3039
3040<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3041<p>The value produced is the floating point difference of the two operands.</p>
3042
3043<h5>Example:</h5>
3044<pre>
3045 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3046 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3047</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3048
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3049</div>
3050
3051<!-- _______________________________________________________________________ -->
3052<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3053 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3054</div>
3055
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3056<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3057
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3058<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3059<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3060 &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]3061 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3062 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3063 &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]3064</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3065
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3066<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3067<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3068
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3069<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3070<p>The two arguments to the '<tt>mul</tt>' instruction must
3071 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3072 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3073
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3074<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3075<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3076
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3077<p>If the result of the multiplication has unsigned overflow, the result
3078 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3079 width of the result.</p>
3080
3081<p>Because LLVM integers use a two's complement representation, and the result
3082 is the same width as the operands, this instruction returns the correct
3083 result for both signed and unsigned integers. If a full product
3084 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3085 be sign-extended or zero-extended as appropriate to the width of the full
3086 product.</p>
3087
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3088<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3089 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3090 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3091 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3092
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3093<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3094<pre>
3095 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3096</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3097
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3098</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3099
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3100<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3101<div class="doc_subsubsection">
3102 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3103</div>
3104
3105<div class="doc_text">
3106
3107<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3108<pre>
3109 &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]3110</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3111
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3112<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3113<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3114
3115<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3116<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3117 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3118 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3119
3120<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3121<p>The value produced is the floating point product of the two operands.</p>
3122
3123<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3124<pre>
3125 &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]3126</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3127
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3128</div>
3129
3130<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3131<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3132</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3133
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3134<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3135
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3136<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3137<pre>
3138 &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]3139</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3140
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3141<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3142<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3143
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3144<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3145<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3146 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3147 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3148
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3149<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3150<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3151
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3152<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3153 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3154
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3155<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3156
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3157<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3158<pre>
3159 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3160</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3161
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3162</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3163
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3164<!-- _______________________________________________________________________ -->
3165<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3166</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3167
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3168<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3169
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3170<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3171<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3172 &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]3173 &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]3174</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3175
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3176<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3177<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3178
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3179<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3180<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3181 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3182 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3183
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3184<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3185<p>The value produced is the signed integer quotient of the two operands rounded
3186 towards zero.</p>
3187
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3188<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3189 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3190
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3191<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3192 undefined behavior; this is a rare case, but can occur, for example, by doing
3193 a 32-bit division of -2147483648 by -1.</p>
3194
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3195<p>If the <tt>exact</tt> keyword is present, the result value of the
3196 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3197 would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3198
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3199<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3200<pre>
3201 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3202</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3203
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3204</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3205
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3206<!-- _______________________________________________________________________ -->
3207<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3208Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3209
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3210<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3211
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3212<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3213<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3214 &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]3215</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3216
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3217<h5>Overview:</h5>
3218<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3219
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3220<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3221<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3222 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3223 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3224
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3225<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3226<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3227
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3228<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3229<pre>
3230 &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]3231</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3232
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3233</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3234
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3235<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3236<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3237</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3238
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3239<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3240
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3241<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3242<pre>
3243 &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]3244</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3245
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3246<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3247<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3248 division of its two arguments.</p>
3249
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3250<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3251<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3252 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3253 values. Both arguments must have identical types.</p>
3254
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3255<h5>Semantics:</h5>
3256<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3257 This instruction always performs an unsigned division to get the
3258 remainder.</p>
3259
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3260<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3261 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3262
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3263<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3264
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3265<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3266<pre>
3267 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3268</pre>
3269
3270</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3271
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3272<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3273<div class="doc_subsubsection">
3274 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3275</div>
3276
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3277<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3278
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3279<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3280<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3281 &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]3282</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3283
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3284<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3285<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3286 division of its two operands. This instruction can also take
3287 <a href="#t_vector">vector</a> versions of the values in which case the
3288 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3289
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3290<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3291<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3292 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3293 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3294
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3295<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3296<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3297 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3298 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3299 a value. For more information about the difference,
3300 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3301 Math Forum</a>. For a table of how this is implemented in various languages,
3302 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3303 Wikipedia: modulo operation</a>.</p>
3304
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3305<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3306 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3307
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3308<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3309 Overflow also leads to undefined behavior; this is a rare case, but can
3310 occur, for example, by taking the remainder of a 32-bit division of
3311 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3312 lets srem be implemented using instructions that return both the result of
3313 the division and the remainder.)</p>
3314
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3315<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3316<pre>
3317 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3318</pre>
3319
3320</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3321
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3322<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3323<div class="doc_subsubsection">
3324 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3325
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3326<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3327
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3328<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3329<pre>
3330 &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]3331</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3332
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3333<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3334<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3335 its two operands.</p>
3336
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3337<h5>Arguments:</h5>
3338<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3339 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3340 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3341
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3342<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3343<p>This instruction returns the <i>remainder</i> of a division. The remainder
3344 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3345
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3346<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3347<pre>
3348 &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]3349</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3350
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3351</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3352
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3353<!-- ======================================================================= -->
3354<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3355Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3356
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3357<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3358
3359<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3360 program. They are generally very efficient instructions and can commonly be
3361 strength reduced from other instructions. They require two operands of the
3362 same type, execute an operation on them, and produce a single value. The
3363 resulting value is the same type as its operands.</p>
3364
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3365</div>
3366
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3367<!-- _______________________________________________________________________ -->
3368<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3369Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3370
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3371<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3372
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3373<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3374<pre>
3375 &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]3376</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3377
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3378<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3379<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3380 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3381
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3382<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3383<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3384 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3385 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3386
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3387<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3388<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3389 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3390 is (statically or dynamically) negative or equal to or larger than the number
3391 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3392 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3393 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3395<h5>Example:</h5>
3396<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3397 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3398 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3399 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3400 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3401 &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]3402</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3403
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3404</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3405
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3406<!-- _______________________________________________________________________ -->
3407<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3408Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3409
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3410<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3411
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3412<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3413<pre>
3414 &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]3415</pre>
3416
3417<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3418<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3419 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3420
3421<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3422<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3423 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3424 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3425
3426<h5>Semantics:</h5>
3427<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3428 significant bits of the result will be filled with zero bits after the shift.
3429 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3430 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3431 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3432 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3433
3434<h5>Example:</h5>
3435<pre>
3436 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3437 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3438 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3439 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3440 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3441 &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]3442</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3443
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3444</div>
3445
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3446<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3447<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3448Instruction</a> </div>
3449<div class="doc_text">
3450
3451<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452<pre>
3453 &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]3454</pre>
3455
3456<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3457<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3458 operand shifted to the right a specified number of bits with sign
3459 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3460
3461<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3462<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3463 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3464 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3465
3466<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3467<p>This instruction always performs an arithmetic shift right operation, The
3468 most significant bits of the result will be filled with the sign bit
3469 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3470 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3471 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3472 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3473
3474<h5>Example:</h5>
3475<pre>
3476 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3477 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3478 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3479 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3480 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3481 &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]3482</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3483
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3484</div>
3485
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3486<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3487<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3488Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3489
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3490<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3491
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3492<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3493<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3494 &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]3495</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3496
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3497<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3498<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3499 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3500
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3501<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3502<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3503 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3504 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3505
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3506<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3507<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3509<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3510 <tbody>
3511 <tr>
3512 <td>In0</td>
3513 <td>In1</td>
3514 <td>Out</td>
3515 </tr>
3516 <tr>
3517 <td>0</td>
3518 <td>0</td>
3519 <td>0</td>
3520 </tr>
3521 <tr>
3522 <td>0</td>
3523 <td>1</td>
3524 <td>0</td>
3525 </tr>
3526 <tr>
3527 <td>1</td>
3528 <td>0</td>
3529 <td>0</td>
3530 </tr>
3531 <tr>
3532 <td>1</td>
3533 <td>1</td>
3534 <td>1</td>
3535 </tr>
3536 </tbody>
3537</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3538
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3539<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3540<pre>
3541 &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]3542 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3543 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3544</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3545</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3546<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3547<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3548
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3549<div class="doc_text">
3550
3551<h5>Syntax:</h5>
3552<pre>
3553 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3554</pre>
3555
3556<h5>Overview:</h5>
3557<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3558 two operands.</p>
3559
3560<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3561<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3562 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3563 values. Both arguments must have identical types.</p>
3564
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3565<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3566<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3567
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3568<table border="1" cellspacing="0" cellpadding="4">
3569 <tbody>
3570 <tr>
3571 <td>In0</td>
3572 <td>In1</td>
3573 <td>Out</td>
3574 </tr>
3575 <tr>
3576 <td>0</td>
3577 <td>0</td>
3578 <td>0</td>
3579 </tr>
3580 <tr>
3581 <td>0</td>
3582 <td>1</td>
3583 <td>1</td>
3584 </tr>
3585 <tr>
3586 <td>1</td>
3587 <td>0</td>
3588 <td>1</td>
3589 </tr>
3590 <tr>
3591 <td>1</td>
3592 <td>1</td>
3593 <td>1</td>
3594 </tr>
3595 </tbody>
3596</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3597
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3598<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3599<pre>
3600 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3601 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3602 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3603</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3604
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3605</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3606
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3607<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3608<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3609Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3610
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3611<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3612
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3613<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3614<pre>
3615 &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]3616</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3617
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3618<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3619<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3620 its two operands. The <tt>xor</tt> is used to implement the "one's
3621 complement" operation, which is the "~" operator in C.</p>
3622
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3623<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3624<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3625 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3626 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3627
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3628<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3629<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3630
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3631<table border="1" cellspacing="0" cellpadding="4">
3632 <tbody>
3633 <tr>
3634 <td>In0</td>
3635 <td>In1</td>
3636 <td>Out</td>
3637 </tr>
3638 <tr>
3639 <td>0</td>
3640 <td>0</td>
3641 <td>0</td>
3642 </tr>
3643 <tr>
3644 <td>0</td>
3645 <td>1</td>
3646 <td>1</td>
3647 </tr>
3648 <tr>
3649 <td>1</td>
3650 <td>0</td>
3651 <td>1</td>
3652 </tr>
3653 <tr>
3654 <td>1</td>
3655 <td>1</td>
3656 <td>0</td>
3657 </tr>
3658 </tbody>
3659</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3660
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3661<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3662<pre>
3663 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3664 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3665 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3666 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3667</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3668
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3669</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3670
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3671<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3672<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3673 <a name="vectorops">Vector Operations</a>
3674</div>
3675
3676<div class="doc_text">
3677
3678<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3679 target-independent manner. These instructions cover the element-access and
3680 vector-specific operations needed to process vectors effectively. While LLVM
3681 does directly support these vector operations, many sophisticated algorithms
3682 will want to use target-specific intrinsics to take full advantage of a
3683 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3684
3685</div>
3686
3687<!-- _______________________________________________________________________ -->
3688<div class="doc_subsubsection">
3689 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3690</div>
3691
3692<div class="doc_text">
3693
3694<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3695<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3696 &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]3697</pre>
3698
3699<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3700<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3701 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3702
3703
3704<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3705<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3706 of <a href="#t_vector">vector</a> type. The second operand is an index
3707 indicating the position from which to extract the element. The index may be
3708 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3709
3710<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3711<p>The result is a scalar of the same type as the element type of
3712 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3713 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3714 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3715
3716<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3717<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3718 &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]3719</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3720
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3721</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3722
3723<!-- _______________________________________________________________________ -->
3724<div class="doc_subsubsection">
3725 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3726</div>
3727
3728<div class="doc_text">
3729
3730<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3731<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]3732 &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]3733</pre>
3734
3735<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3736<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3737 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3738
3739<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3740<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3741 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3742 whose type must equal the element type of the first operand. The third
3743 operand is an index indicating the position at which to insert the value.
3744 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3745
3746<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3747<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3748 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3749 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3750 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3751
3752<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3753<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3754 &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]3755</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3756
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3757</div>
3758
3759<!-- _______________________________________________________________________ -->
3760<div class="doc_subsubsection">
3761 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3762</div>
3763
3764<div class="doc_text">
3765
3766<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3767<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3768 &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]3769</pre>
3770
3771<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3772<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3773 from two input vectors, returning a vector with the same element type as the
3774 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3775
3776<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3777<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3778 with types that match each other. The third argument is a shuffle mask whose
3779 element type is always 'i32'. The result of the instruction is a vector
3780 whose length is the same as the shuffle mask and whose element type is the
3781 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3782
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3783<p>The shuffle mask operand is required to be a constant vector with either
3784 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3785
3786<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3787<p>The elements of the two input vectors are numbered from left to right across
3788 both of the vectors. The shuffle mask operand specifies, for each element of
3789 the result vector, which element of the two input vectors the result element
3790 gets. The element selector may be undef (meaning "don't care") and the
3791 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3792
3793<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3794<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3795 &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]3796 &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]3797 &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]3798 &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]3799 &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]3800 &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]3801 &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]3802 &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]3803</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3804
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3805</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]3806
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3807<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3808<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3809 <a name="aggregateops">Aggregate Operations</a>
3810</div>
3811
3812<div class="doc_text">
3813
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3814<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3815
3816</div>
3817
3818<!-- _______________________________________________________________________ -->
3819<div class="doc_subsubsection">
3820 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3821</div>
3822
3823<div class="doc_text">
3824
3825<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3826<pre>
3827 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3828</pre>
3829
3830<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3831<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3832 or array element from an aggregate value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3833
3834<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3835<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3836 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3837 operands are constant indices to specify which value to extract in a similar
3838 manner as indices in a
3839 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3840
3841<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3842<p>The result is the value at the position in the aggregate specified by the
3843 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3844
3845<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3846<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3847 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3848</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3849
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3850</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3851
3852<!-- _______________________________________________________________________ -->
3853<div class="doc_subsubsection">
3854 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3855</div>
3856
3857<div class="doc_text">
3858
3859<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3860<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3861 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3862</pre>
3863
3864<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3865<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3866 array element in an aggregate.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3867
3868
3869<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3870<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3871 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3872 second operand is a first-class value to insert. The following operands are
3873 constant indices indicating the position at which to insert the value in a
3874 similar manner as indices in a
3875 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3876 value to insert must have the same type as the value identified by the
3877 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3878
3879<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3880<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3881 that of <tt>val</tt> except that the value at the position specified by the
3882 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3883
3884<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3885<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3886 &lt;result&gt; = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3887</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3888
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3889</div>
3890
3891
3892<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3893<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3894 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3895</div>
3896
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3897<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3898
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3899<p>A key design point of an SSA-based representation is how it represents
3900 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]3901 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3902 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3903
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3904</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3906<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3907<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3908 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3909</div>
3910
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3911<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3912
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3913<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3914<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3915 &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]3916</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3917
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3918<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3919<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3920 currently executing function, to be automatically released when this function
3921 returns to its caller. The object is always allocated in the generic address
3922 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3923
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3924<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3925<p>The '<tt>alloca</tt>' instruction
3926 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3927 runtime stack, returning a pointer of the appropriate type to the program.
3928 If "NumElements" is specified, it is the number of elements allocated,
3929 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3930 specified, the value result of the allocation is guaranteed to be aligned to
3931 at least that boundary. If not specified, or if zero, the target can choose
3932 to align the allocation on any convenient boundary compatible with the
3933 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3934
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3935<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3937<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]3938<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3939 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3940 memory is automatically released when the function returns. The
3941 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3942 variables that must have an address available. When the function returns
3943 (either with the <tt><a href="#i_ret">ret</a></tt>
3944 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3945 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3946
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3947<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3948<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3949 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3950 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3951 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3952 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3953</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3954
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3955</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3956
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3957<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3958<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3959Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3960
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3961<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3963<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3964<pre>
3965 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3966 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3967</pre>
3968
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3969<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3970<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3971
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3972<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3973<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3974 from which to load. The pointer must point to
3975 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3976 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3977 number or order of execution of this <tt>load</tt> with other
3978 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3979 instructions. </p>
3980
3981<p>The optional constant "align" argument specifies the alignment of the
3982 operation (that is, the alignment of the memory address). A value of 0 or an
3983 omitted "align" argument means that the operation has the preferential
3984 alignment for the target. It is the responsibility of the code emitter to
3985 ensure that the alignment information is correct. Overestimating the
3986 alignment results in an undefined behavior. Underestimating the alignment may
3987 produce less efficient code. An alignment of 1 is always safe.</p>
3988
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3989<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3990<p>The location of memory pointed to is loaded. If the value being loaded is of
3991 scalar type then the number of bytes read does not exceed the minimum number
3992 of bytes needed to hold all bits of the type. For example, loading an
3993 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3994 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3995 is undefined if the value was not originally written using a store of the
3996 same type.</p>
3997
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3998<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3999<pre>
4000 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4001 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4002 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4003</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4004
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4005</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4006
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4007<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4008<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4009Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4010
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4011<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4012
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4013<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4014<pre>
4015 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]4016 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4017</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4018
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4019<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4020<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4021
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4022<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4023<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4024 and an address at which to store it. The type of the
4025 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4026 the <a href="#t_firstclass">first class</a> type of the
4027 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4028 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4029 or order of execution of this <tt>store</tt> with other
4030 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4031 instructions.</p>
4032
4033<p>The optional constant "align" argument specifies the alignment of the
4034 operation (that is, the alignment of the memory address). A value of 0 or an
4035 omitted "align" argument means that the operation has the preferential
4036 alignment for the target. It is the responsibility of the code emitter to
4037 ensure that the alignment information is correct. Overestimating the
4038 alignment results in an undefined behavior. Underestimating the alignment may
4039 produce less efficient code. An alignment of 1 is always safe.</p>
4040
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4041<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4042<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4043 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4044 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4045 does not exceed the minimum number of bytes needed to hold all bits of the
4046 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4047 writing a value of a type like <tt>i20</tt> with a size that is not an
4048 integral number of bytes, it is unspecified what happens to the extra bits
4049 that do not belong to the type, but they will typically be overwritten.</p>
4050
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4051<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4052<pre>
4053 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4054 store i32 3, i32* %ptr <i>; yields {void}</i>
4055 %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]4056</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4057
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4058</div>
4059
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4060<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4061<div class="doc_subsubsection">
4062 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4063</div>
4064
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4065<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4066
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4067<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4068<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4069 &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]4070 &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]4071</pre>
4072
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4073<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4074<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4075 subelement of an aggregate data structure. It performs address calculation
4076 only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4077
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4078<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4079<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4080 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4081 elements of the aggregate object are indexed. The interpretation of each
4082 index is dependent on the type being indexed into. The first index always
4083 indexes the pointer value given as the first argument, the second index
4084 indexes a value of the type pointed to (not necessarily the value directly
4085 pointed to, since the first index can be non-zero), etc. The first type
4086 indexed into must be a pointer value, subsequent types can be arrays, vectors
4087 and structs. Note that subsequent types being indexed into can never be
4088 pointers, since that would require loading the pointer before continuing
4089 calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4090
4091<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4092 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4093 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4094 vector, integers of any width are allowed, and they are not required to be
4095 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4096
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4097<p>For example, let's consider a C code fragment and how it gets compiled to
4098 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4099
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4100<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4101<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4102struct RT {
4103 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4104 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4105 char C;
4106};
4107struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4108 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4109 double Y;
4110 struct RT Z;
4111};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4112
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4113int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4114 return &amp;s[1].Z.B[5][13];
4115}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4116</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4117</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4118
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4119<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4120
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4121<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4122<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4123%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4124%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4125
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4126define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4127entry:
4128 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4129 ret i32* %reg
4130}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4131</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4132</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4133
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4134<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4135<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]4136 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4137 }</tt>' type, a structure. The second index indexes into the third element
4138 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4139 i8 }</tt>' type, another structure. The third index indexes into the second
4140 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4141 array. The two dimensions of the array are subscripted into, yielding an
4142 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4143 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4144
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4145<p>Note that it is perfectly legal to index partially through a structure,
4146 returning a pointer to an inner element. Because of this, the LLVM code for
4147 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4148
4149<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4150 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4151 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4152 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4153 %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]4154 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4155 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4156 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4157 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4158</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4159
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4160<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4161 <tt>getelementptr</tt> is undefined if the base pointer is not an
4162 <i>in bounds</i> address of an allocated object, or if any of the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4163 that would be formed by successive addition of the offsets implied by the
4164 indices to the base address with infinitely precise arithmetic are not an
4165 <i>in bounds</i> address of that allocated object.
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4166 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4167 that point into the object, plus the address one byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4168
4169<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4170 the base address with silently-wrapping two's complement arithmetic, and
4171 the result value of the <tt>getelementptr</tt> may be outside the object
4172 pointed to by the base pointer. The result value may not necessarily be
4173 used to access memory though, even if it happens to point into allocated
4174 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4175 section for more information.</p>
4176
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4177<p>The getelementptr instruction is often confusing. For some more insight into
4178 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4179
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4180<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4181<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4182 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4183 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4184 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4185 %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]4186 <i>; yields i8*:eptr</i>
4187 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4188 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4189 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4190</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4191
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4192</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4193
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4194<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4195<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4196</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4197
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4198<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4199
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4200<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4201 which all take a single operand and a type. They perform various bit
4202 conversions on the operand.</p>
4203
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4204</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4205
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4206<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4207<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4208 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4209</div>
4210<div class="doc_text">
4211
4212<h5>Syntax:</h5>
4213<pre>
4214 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4215</pre>
4216
4217<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4218<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4219 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4220
4221<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4222<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4223 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4224 size and type of the result, which must be
4225 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4226 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4227 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4228
4229<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4230<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4231 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4232 source size must be larger than the destination size, <tt>trunc</tt> cannot
4233 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4234
4235<h5>Example:</h5>
4236<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4237 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4238 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4239 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4240</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4241
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4242</div>
4243
4244<!-- _______________________________________________________________________ -->
4245<div class="doc_subsubsection">
4246 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4247</div>
4248<div class="doc_text">
4249
4250<h5>Syntax:</h5>
4251<pre>
4252 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4253</pre>
4254
4255<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4256<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4257 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4258
4259
4260<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4261<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]4262 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4263 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]4264 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4265 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4266
4267<h5>Semantics:</h5>
4268<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]4269 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4270
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4271<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]4272
4273<h5>Example:</h5>
4274<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4275 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4276 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4277</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4278
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4279</div>
4280
4281<!-- _______________________________________________________________________ -->
4282<div class="doc_subsubsection">
4283 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4284</div>
4285<div class="doc_text">
4286
4287<h5>Syntax:</h5>
4288<pre>
4289 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4290</pre>
4291
4292<h5>Overview:</h5>
4293<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4294
4295<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4296<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]4297 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4298 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]4299 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4300 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4301
4302<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4303<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4304 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4305 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4306
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4307<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]4308
4309<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4310<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4311 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4312 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4313</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4314
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4315</div>
4316
4317<!-- _______________________________________________________________________ -->
4318<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4319 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4320</div>
4321
4322<div class="doc_text">
4323
4324<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4325<pre>
4326 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4327</pre>
4328
4329<h5>Overview:</h5>
4330<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4331 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4332
4333<h5>Arguments:</h5>
4334<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4335 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4336 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]4337 <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]4338 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4339
4340<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4341<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4342 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4343 <a href="#t_floating">floating point</a> type. If the value cannot fit
4344 within the destination type, <tt>ty2</tt>, then the results are
4345 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4346
4347<h5>Example:</h5>
4348<pre>
4349 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4350 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4351</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4352
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4353</div>
4354
4355<!-- _______________________________________________________________________ -->
4356<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4357 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4358</div>
4359<div class="doc_text">
4360
4361<h5>Syntax:</h5>
4362<pre>
4363 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4364</pre>
4365
4366<h5>Overview:</h5>
4367<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]4368 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4369
4370<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4371<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4372 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4373 a <a href="#t_floating">floating point</a> type to cast it to. The source
4374 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4375
4376<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4377<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4378 <a href="#t_floating">floating point</a> type to a larger
4379 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4380 used to make a <i>no-op cast</i> because it always changes bits. Use
4381 <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]4382
4383<h5>Example:</h5>
4384<pre>
4385 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4386 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4387</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4388
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4389</div>
4390
4391<!-- _______________________________________________________________________ -->
4392<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4393 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4394</div>
4395<div class="doc_text">
4396
4397<h5>Syntax:</h5>
4398<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4399 &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]4400</pre>
4401
4402<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4403<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4404 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4405
4406<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4407<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4408 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4409 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4410 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4411 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4412
4413<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4414<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4415 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4416 towards zero) unsigned integer value. If the value cannot fit
4417 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4418
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4419<h5>Example:</h5>
4420<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4421 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4422 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4423 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4424</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4425
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4426</div>
4427
4428<!-- _______________________________________________________________________ -->
4429<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4430 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4431</div>
4432<div class="doc_text">
4433
4434<h5>Syntax:</h5>
4435<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4436 &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]4437</pre>
4438
4439<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4440<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4441 <a href="#t_floating">floating point</a> <tt>value</tt> to
4442 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4443
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4444<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4445<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4446 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4447 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4448 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4449 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4450
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4451<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4452<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4453 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4454 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4455 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4456
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4457<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4458<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4459 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4460 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4461 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4462</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4463
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4464</div>
4465
4466<!-- _______________________________________________________________________ -->
4467<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4468 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4469</div>
4470<div class="doc_text">
4471
4472<h5>Syntax:</h5>
4473<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4474 &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]4475</pre>
4476
4477<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4478<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4479 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4480
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4481<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4482<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]4483 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4484 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4485 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4486 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4487
4488<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4489<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4490 integer quantity and converts it to the corresponding floating point
4491 value. If the value cannot fit in the floating point value, the results are
4492 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4493
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4494<h5>Example:</h5>
4495<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4496 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4497 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4498</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4499
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4500</div>
4501
4502<!-- _______________________________________________________________________ -->
4503<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4504 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4505</div>
4506<div class="doc_text">
4507
4508<h5>Syntax:</h5>
4509<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4510 &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]4511</pre>
4512
4513<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4514<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4515 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4516
4517<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4518<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]4519 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4520 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4521 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4522 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4523
4524<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4525<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4526 quantity and converts it to the corresponding floating point value. If the
4527 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4528
4529<h5>Example:</h5>
4530<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4531 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4532 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4533</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4534
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4535</div>
4536
4537<!-- _______________________________________________________________________ -->
4538<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4539 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4540</div>
4541<div class="doc_text">
4542
4543<h5>Syntax:</h5>
4544<pre>
4545 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4546</pre>
4547
4548<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4549<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4550 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4551
4552<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4553<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4554 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4555 <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]4556
4557<h5>Semantics:</h5>
4558<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4559 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4560 truncating or zero extending that value to the size of the integer type. If
4561 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4562 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4563 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4564 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4565
4566<h5>Example:</h5>
4567<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4568 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4569 %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]4570</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4571
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4572</div>
4573
4574<!-- _______________________________________________________________________ -->
4575<div class="doc_subsubsection">
4576 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4577</div>
4578<div class="doc_text">
4579
4580<h5>Syntax:</h5>
4581<pre>
4582 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4583</pre>
4584
4585<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4586<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4587 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4588
4589<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4590<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4591 value to cast, and a type to cast it to, which must be a
4592 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4593
4594<h5>Semantics:</h5>
4595<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4596 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4597 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4598 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4599 than the size of a pointer then a zero extension is done. If they are the
4600 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4601
4602<h5>Example:</h5>
4603<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4604 %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]4605 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4606 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4607</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4608
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4609</div>
4610
4611<!-- _______________________________________________________________________ -->
4612<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4613 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4614</div>
4615<div class="doc_text">
4616
4617<h5>Syntax:</h5>
4618<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4619 &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]4620</pre>
4621
4622<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4623<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4624 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4625
4626<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4627<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4628 non-aggregate first class value, and a type to cast it to, which must also be
4629 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4630 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4631 identical. If the source type is a pointer, the destination type must also be
4632 a pointer. This instruction supports bitwise conversion of vectors to
4633 integers and to vectors of other types (as long as they have the same
4634 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4635
4636<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4637<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4638 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4639 this conversion. The conversion is done as if the <tt>value</tt> had been
4640 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4641 be converted to other pointer types with this instruction. To convert
4642 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4643 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4644
4645<h5>Example:</h5>
4646<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4647 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4648 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4649 %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]4650</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4651
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4652</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4653
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4654<!-- ======================================================================= -->
4655<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4656
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4657<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4658
4659<p>The instructions in this category are the "miscellaneous" instructions, which
4660 defy better classification.</p>
4661
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4662</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4663
4664<!-- _______________________________________________________________________ -->
4665<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4666</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4667
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4668<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4669
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4670<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4671<pre>
4672 &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]4673</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4674
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4675<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4676<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4677 boolean values based on comparison of its two integer, integer vector, or
4678 pointer operands.</p>
4679
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4680<h5>Arguments:</h5>
4681<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4682 the condition code indicating the kind of comparison to perform. It is not a
4683 value, just a keyword. The possible condition code are:</p>
4684
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4685<ol>
4686 <li><tt>eq</tt>: equal</li>
4687 <li><tt>ne</tt>: not equal </li>
4688 <li><tt>ugt</tt>: unsigned greater than</li>
4689 <li><tt>uge</tt>: unsigned greater or equal</li>
4690 <li><tt>ult</tt>: unsigned less than</li>
4691 <li><tt>ule</tt>: unsigned less or equal</li>
4692 <li><tt>sgt</tt>: signed greater than</li>
4693 <li><tt>sge</tt>: signed greater or equal</li>
4694 <li><tt>slt</tt>: signed less than</li>
4695 <li><tt>sle</tt>: signed less or equal</li>
4696</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4697
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4698<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4699 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4700 typed. They must also be identical types.</p>
4701
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4702<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4703<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4704 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4705 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]4706 result, as follows:</p>
4707
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4708<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4709 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4710 <tt>false</tt> otherwise. No sign interpretation is necessary or
4711 performed.</li>
4712
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4713 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4714 <tt>false</tt> otherwise. No sign interpretation is necessary or
4715 performed.</li>
4716
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4717 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4718 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4719
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4720 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4721 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4722 to <tt>op2</tt>.</li>
4723
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4724 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4725 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4726
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4727 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4728 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4729
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4730 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4731 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4732
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4733 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4734 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4735 to <tt>op2</tt>.</li>
4736
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4737 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4738 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4739
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4740 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741 <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]4742</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4743
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4744<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4745 values are compared as if they were integers.</p>
4746
4747<p>If the operands are integer vectors, then they are compared element by
4748 element. The result is an <tt>i1</tt> vector with the same number of elements
4749 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4750
4751<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4752<pre>
4753 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4754 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4755 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4756 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4757 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4758 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4759</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4760
4761<p>Note that the code generator does not yet support vector types with
4762 the <tt>icmp</tt> instruction.</p>
4763
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4764</div>
4765
4766<!-- _______________________________________________________________________ -->
4767<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4768</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4769
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4770<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4771
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4772<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4773<pre>
4774 &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]4775</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4776
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4777<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4778<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4779 values based on comparison of its operands.</p>
4780
4781<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]4782(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4783
4784<p>If the operands are floating point vectors, then the result type is a vector
4785 of boolean with the same number of elements as the operands being
4786 compared.</p>
4787
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4788<h5>Arguments:</h5>
4789<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4790 the condition code indicating the kind of comparison to perform. It is not a
4791 value, just a keyword. The possible condition code are:</p>
4792
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4793<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4794 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4795 <li><tt>oeq</tt>: ordered and equal</li>
4796 <li><tt>ogt</tt>: ordered and greater than </li>
4797 <li><tt>oge</tt>: ordered and greater than or equal</li>
4798 <li><tt>olt</tt>: ordered and less than </li>
4799 <li><tt>ole</tt>: ordered and less than or equal</li>
4800 <li><tt>one</tt>: ordered and not equal</li>
4801 <li><tt>ord</tt>: ordered (no nans)</li>
4802 <li><tt>ueq</tt>: unordered or equal</li>
4803 <li><tt>ugt</tt>: unordered or greater than </li>
4804 <li><tt>uge</tt>: unordered or greater than or equal</li>
4805 <li><tt>ult</tt>: unordered or less than </li>
4806 <li><tt>ule</tt>: unordered or less than or equal</li>
4807 <li><tt>une</tt>: unordered or not equal</li>
4808 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4809 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4810</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4811
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4812<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4813 <i>unordered</i> means that either operand may be a QNAN.</p>
4814
4815<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4816 a <a href="#t_floating">floating point</a> type or
4817 a <a href="#t_vector">vector</a> of floating point type. They must have
4818 identical types.</p>
4819
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4820<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4821<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4822 according to the condition code given as <tt>cond</tt>. If the operands are
4823 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4824 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4825 follows:</p>
4826
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4827<ol>
4828 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4829
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4830 <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]4831 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4832
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4833 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4834 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4835
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4836 <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]4837 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4838
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4839 <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]4840 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4841
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4842 <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]4843 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4844
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4845 <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]4846 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4847
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4848 <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]4849
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4850 <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]4851 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4852
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4853 <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]4854 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4855
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4856 <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]4857 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4858
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4859 <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]4860 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4861
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4862 <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]4863 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4864
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4865 <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]4866 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4867
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4868 <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]4869
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4870 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4871</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4872
4873<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4874<pre>
4875 &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]4876 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4877 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4878 &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]4879</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4880
4881<p>Note that the code generator does not yet support vector types with
4882 the <tt>fcmp</tt> instruction.</p>
4883
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4884</div>
4885
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4886<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]4887<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4888 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4889</div>
4890
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4891<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4892
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4893<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4894<pre>
4895 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4896</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4897
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4898<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4899<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4900 SSA graph representing the function.</p>
4901
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4902<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4903<p>The type of the incoming values is specified with the first type field. After
4904 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4905 one pair for each predecessor basic block of the current block. Only values
4906 of <a href="#t_firstclass">first class</a> type may be used as the value
4907 arguments to the PHI node. Only labels may be used as the label
4908 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4909
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4910<p>There must be no non-phi instructions between the start of a basic block and
4911 the PHI instructions: i.e. PHI instructions must be first in a basic
4912 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4913
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4914<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4915 occur on the edge from the corresponding predecessor block to the current
4916 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4917 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]4918
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4919<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4920<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4921 specified by the pair corresponding to the predecessor basic block that
4922 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4923
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4924<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4925<pre>
4926Loop: ; Infinite loop that counts from 0 on up...
4927 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4928 %nextindvar = add i32 %indvar, 1
4929 br label %Loop
4930</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4931
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4932</div>
4933
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4934<!-- _______________________________________________________________________ -->
4935<div class="doc_subsubsection">
4936 <a name="i_select">'<tt>select</tt>' Instruction</a>
4937</div>
4938
4939<div class="doc_text">
4940
4941<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4942<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4943 &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>
4944
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4945 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4946</pre>
4947
4948<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4949<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4950 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4951
4952
4953<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4954<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4955 values indicating the condition, and two values of the
4956 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4957 vectors and the condition is a scalar, then entire vectors are selected, not
4958 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4959
4960<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4961<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4962 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4963
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4964<p>If the condition is a vector of i1, then the value arguments must be vectors
4965 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4966
4967<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4968<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4969 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4970</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4971
4972<p>Note that the code generator does not yet support conditions
4973 with vector type.</p>
4974
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4975</div>
4976
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]4977<!-- _______________________________________________________________________ -->
4978<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4979 <a name="i_call">'<tt>call</tt>' Instruction</a>
4980</div>
4981
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4982<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4983
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4984<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4985<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]4986 &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]4987</pre>
4988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4989<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4990<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4991
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4992<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4993<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4994
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4995<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame^]4996 <li>The optional "tail" marker indicates that the callee function does not
4997 access any allocas or varargs in the caller. Note that calls may be
4998 marked "tail" even if they do not occur before
4999 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5000 present, the function call is eligible for tail call optimization,
5001 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
5002 optimized into a jump</a>. As of this writing, the extra requirements for
5003 a call to actually be optimized are:
5004 <ul>
5005 <li>Caller and callee both have the calling
5006 convention <tt>fastcc</tt>.</li>
5007 <li>The call is in tail position (ret immediately follows call and ret
5008 uses value of call or is void).</li>
5009 <li>Option <tt>-tailcallopt</tt> is enabled,
5010 or <code>llvm::PerformTailCallOpt</code> is <code>true</code>.</li>
5011 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5012 constraints are met.</a></li>
5013 </ul>
5014 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5015
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5016 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5017 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame^]5018 defaults to using C calling conventions. The calling convention of the
5019 call must match the calling convention of the target function, or else the
5020 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5021
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5022 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5023 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5024 '<tt>inreg</tt>' attributes are valid here.</li>
5025
5026 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5027 type of the return value. Functions that return no value are marked
5028 <tt><a href="#t_void">void</a></tt>.</li>
5029
5030 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5031 being invoked. The argument types must match the types implied by this
5032 signature. This type can be omitted if the function is not varargs and if
5033 the function type does not return a pointer to a function.</li>
5034
5035 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5036 be invoked. In most cases, this is a direct function invocation, but
5037 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5038 to function value.</li>
5039
5040 <li>'<tt>function args</tt>': argument list whose types match the function
5041 signature argument types. All arguments must be of
5042 <a href="#t_firstclass">first class</a> type. If the function signature
5043 indicates the function accepts a variable number of arguments, the extra
5044 arguments can be specified.</li>
5045
5046 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5047 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5048 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5049</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5050
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5051<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5052<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5053 a specified function, with its incoming arguments bound to the specified
5054 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5055 function, control flow continues with the instruction after the function
5056 call, and the return value of the function is bound to the result
5057 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5058
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5059<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5060<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5061 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5062 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5063 %X = tail call i32 @foo() <i>; yields i32</i>
5064 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5065 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5066
5067 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5068 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5069 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5070 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5071 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5072 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5073</pre>
5074
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5075<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5076standard C99 library as being the C99 library functions, and may perform
5077optimizations or generate code for them under that assumption. This is
5078something we'd like to change in the future to provide better support for
5079freestanding environments and non-C-based langauges.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5080
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5081</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5082
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5083<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5084<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5085 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5086</div>
5087
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5088<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5089
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5090<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5091<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5092 &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]5093</pre>
5094
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5095<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5096<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5097 the "variable argument" area of a function call. It is used to implement the
5098 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5099
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5100<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5101<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5102 argument. It returns a value of the specified argument type and increments
5103 the <tt>va_list</tt> to point to the next argument. The actual type
5104 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5105
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5106<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5107<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5108 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5109 to the next argument. For more information, see the variable argument
5110 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5111
5112<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]5113 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5114 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5115
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5116<p><tt>va_arg</tt> is an LLVM instruction instead of
5117 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5118 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5119
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5120<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5121<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5122
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5123<p>Note that the code generator does not yet fully support va_arg on many
5124 targets. Also, it does not currently support va_arg with aggregate types on
5125 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5126
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5127</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5128
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5129<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5130<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5131<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5132
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5133<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5134
5135<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5136 well known names and semantics and are required to follow certain
5137 restrictions. Overall, these intrinsics represent an extension mechanism for
5138 the LLVM language that does not require changing all of the transformations
5139 in LLVM when adding to the language (or the bitcode reader/writer, the
5140 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5141
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5142<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5143 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5144 begin with this prefix. Intrinsic functions must always be external
5145 functions: you cannot define the body of intrinsic functions. Intrinsic
5146 functions may only be used in call or invoke instructions: it is illegal to
5147 take the address of an intrinsic function. Additionally, because intrinsic
5148 functions are part of the LLVM language, it is required if any are added that
5149 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5150
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5151<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5152 family of functions that perform the same operation but on different data
5153 types. Because LLVM can represent over 8 million different integer types,
5154 overloading is used commonly to allow an intrinsic function to operate on any
5155 integer type. One or more of the argument types or the result type can be
5156 overloaded to accept any integer type. Argument types may also be defined as
5157 exactly matching a previous argument's type or the result type. This allows
5158 an intrinsic function which accepts multiple arguments, but needs all of them
5159 to be of the same type, to only be overloaded with respect to a single
5160 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5161
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5162<p>Overloaded intrinsics will have the names of its overloaded argument types
5163 encoded into its function name, each preceded by a period. Only those types
5164 which are overloaded result in a name suffix. Arguments whose type is matched
5165 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5166 can take an integer of any width and returns an integer of exactly the same
5167 integer width. This leads to a family of functions such as
5168 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5169 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5170 suffix is required. Because the argument's type is matched against the return
5171 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5172
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5173<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5174 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5175
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5176</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5177
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5178<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5179<div class="doc_subsection">
5180 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5181</div>
5182
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5183<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5184
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5185<p>Variable argument support is defined in LLVM with
5186 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5187 intrinsic functions. These functions are related to the similarly named
5188 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5189
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5190<p>All of these functions operate on arguments that use a target-specific value
5191 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5192 not define what this type is, so all transformations should be prepared to
5193 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5194
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5195<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]5196 instruction and the variable argument handling intrinsic functions are
5197 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5198
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5199<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5200<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5201define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5202 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5203 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5204 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5205 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5206
5207 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5208 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5209
5210 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5211 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5212 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5213 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5214 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5215
5216 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5217 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5218 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5219}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5220
5221declare void @llvm.va_start(i8*)
5222declare void @llvm.va_copy(i8*, i8*)
5223declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5224</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5225</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5226
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5227</div>
5228
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5229<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5230<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5231 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5232</div>
5233
5234
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5235<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5236
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5237<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5238<pre>
5239 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5240</pre>
5241
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5242<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5243<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5244 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]5245
5246<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5247<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]5248
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5249<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5250<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]5251 macro available in C. In a target-dependent way, it initializes
5252 the <tt>va_list</tt> element to which the argument points, so that the next
5253 call to <tt>va_arg</tt> will produce the first variable argument passed to
5254 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5255 need to know the last argument of the function as the compiler can figure
5256 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5257
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5258</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5259
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5260<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5261<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5262 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5263</div>
5264
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5265<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5266
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5267<h5>Syntax:</h5>
5268<pre>
5269 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5270</pre>
5271
5272<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5273<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5274 which has been initialized previously
5275 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5276 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5277
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5278<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5279<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]5280
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5281<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5282<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]5283 macro available in C. In a target-dependent way, it destroys
5284 the <tt>va_list</tt> element to which the argument points. Calls
5285 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5286 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5287 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5288
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5289</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5290
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5291<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5292<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5293 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5294</div>
5295
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5296<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5297
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5298<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5299<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5300 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5301</pre>
5302
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5303<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5304<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5305 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5306
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5307<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5308<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]5309 The second argument is a pointer to a <tt>va_list</tt> element to copy
5310 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5311
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5312<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5313<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]5314 macro available in C. In a target-dependent way, it copies the
5315 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5316 element. This intrinsic is necessary because
5317 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5318 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5319
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5320</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5321
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5322<!-- ======================================================================= -->
5323<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5324 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5325</div>
5326
5327<div class="doc_text">
5328
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5329<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5330Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5331intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5332roots on the stack</a>, as well as garbage collector implementations that
5333require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5334barriers. Front-ends for type-safe garbage collected languages should generate
5335these intrinsics to make use of the LLVM garbage collectors. For more details,
5336see <a href="GarbageCollection.html">Accurate Garbage Collection with
5337LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5338
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5339<p>The garbage collection intrinsics only operate on objects in the generic
5340 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5341
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5342</div>
5343
5344<!-- _______________________________________________________________________ -->
5345<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5346 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5347</div>
5348
5349<div class="doc_text">
5350
5351<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5352<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5353 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5354</pre>
5355
5356<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5357<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]5358 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5359
5360<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5361<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5362 root pointer. The second pointer (which must be either a constant or a
5363 global value address) contains the meta-data to be associated with the
5364 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5365
5366<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5367<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]5368 location. At compile-time, the code generator generates information to allow
5369 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5370 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5371 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5372
5373</div>
5374
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5375<!-- _______________________________________________________________________ -->
5376<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5377 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5378</div>
5379
5380<div class="doc_text">
5381
5382<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5383<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5384 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5385</pre>
5386
5387<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5388<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5389 locations, allowing garbage collector implementations that require read
5390 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5391
5392<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5393<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]5394 allocated from the garbage collector. The first object is a pointer to the
5395 start of the referenced object, if needed by the language runtime (otherwise
5396 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5397
5398<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5399<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5400 instruction, but may be replaced with substantially more complex code by the
5401 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5402 may only be used in a function which <a href="#gc">specifies a GC
5403 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5404
5405</div>
5406
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5407<!-- _______________________________________________________________________ -->
5408<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5409 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5410</div>
5411
5412<div class="doc_text">
5413
5414<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5415<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5416 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5417</pre>
5418
5419<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5420<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5421 locations, allowing garbage collector implementations that require write
5422 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5423
5424<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5425<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]5426 object to store it to, and the third is the address of the field of Obj to
5427 store to. If the runtime does not require a pointer to the object, Obj may
5428 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5429
5430<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5431<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5432 instruction, but may be replaced with substantially more complex code by the
5433 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5434 may only be used in a function which <a href="#gc">specifies a GC
5435 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5436
5437</div>
5438
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5439<!-- ======================================================================= -->
5440<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5441 <a name="int_codegen">Code Generator Intrinsics</a>
5442</div>
5443
5444<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5445
5446<p>These intrinsics are provided by LLVM to expose special features that may
5447 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5448
5449</div>
5450
5451<!-- _______________________________________________________________________ -->
5452<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5453 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5454</div>
5455
5456<div class="doc_text">
5457
5458<h5>Syntax:</h5>
5459<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5460 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5461</pre>
5462
5463<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5464<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5465 target-specific value indicating the return address of the current function
5466 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5467
5468<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5469<p>The argument to this intrinsic indicates which function to return the address
5470 for. Zero indicates the calling function, one indicates its caller, etc.
5471 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5472
5473<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5474<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5475 indicating the return address of the specified call frame, or zero if it
5476 cannot be identified. The value returned by this intrinsic is likely to be
5477 incorrect or 0 for arguments other than zero, so it should only be used for
5478 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5479
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5480<p>Note that calling this intrinsic does not prevent function inlining or other
5481 aggressive transformations, so the value returned may not be that of the
5482 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5483
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5484</div>
5485
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5486<!-- _______________________________________________________________________ -->
5487<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5488 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5489</div>
5490
5491<div class="doc_text">
5492
5493<h5>Syntax:</h5>
5494<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5495 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5496</pre>
5497
5498<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5499<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5500 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5501
5502<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5503<p>The argument to this intrinsic indicates which function to return the frame
5504 pointer for. Zero indicates the calling function, one indicates its caller,
5505 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5506
5507<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5508<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5509 indicating the frame address of the specified call frame, or zero if it
5510 cannot be identified. The value returned by this intrinsic is likely to be
5511 incorrect or 0 for arguments other than zero, so it should only be used for
5512 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5513
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5514<p>Note that calling this intrinsic does not prevent function inlining or other
5515 aggressive transformations, so the value returned may not be that of the
5516 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5517
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5518</div>
5519
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5520<!-- _______________________________________________________________________ -->
5521<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5522 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5523</div>
5524
5525<div class="doc_text">
5526
5527<h5>Syntax:</h5>
5528<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5529 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5530</pre>
5531
5532<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5533<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5534 of the function stack, for use
5535 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5536 useful for implementing language features like scoped automatic variable
5537 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5538
5539<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5540<p>This intrinsic returns a opaque pointer value that can be passed
5541 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5542 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5543 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5544 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5545 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5546 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5547
5548</div>
5549
5550<!-- _______________________________________________________________________ -->
5551<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5552 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5553</div>
5554
5555<div class="doc_text">
5556
5557<h5>Syntax:</h5>
5558<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5559 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5560</pre>
5561
5562<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5563<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5564 the function stack to the state it was in when the
5565 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5566 executed. This is useful for implementing language features like scoped
5567 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5568
5569<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5570<p>See the description
5571 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5572
5573</div>
5574
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5575<!-- _______________________________________________________________________ -->
5576<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5577 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5578</div>
5579
5580<div class="doc_text">
5581
5582<h5>Syntax:</h5>
5583<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5584 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]5585</pre>
5586
5587<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5588<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5589 insert a prefetch instruction if supported; otherwise, it is a noop.
5590 Prefetches have no effect on the behavior of the program but can change its
5591 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5592
5593<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5594<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5595 specifier determining if the fetch should be for a read (0) or write (1),
5596 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5597 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5598 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5599
5600<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5601<p>This intrinsic does not modify the behavior of the program. In particular,
5602 prefetches cannot trap and do not produce a value. On targets that support
5603 this intrinsic, the prefetch can provide hints to the processor cache for
5604 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5605
5606</div>
5607
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5608<!-- _______________________________________________________________________ -->
5609<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5610 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5611</div>
5612
5613<div class="doc_text">
5614
5615<h5>Syntax:</h5>
5616<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5617 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5618</pre>
5619
5620<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5621<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5622 Counter (PC) in a region of code to simulators and other tools. The method
5623 is target specific, but it is expected that the marker will use exported
5624 symbols to transmit the PC of the marker. The marker makes no guarantees
5625 that it will remain with any specific instruction after optimizations. It is
5626 possible that the presence of a marker will inhibit optimizations. The
5627 intended use is to be inserted after optimizations to allow correlations of
5628 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5629
5630<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5631<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5632
5633<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5634<p>This intrinsic does not modify the behavior of the program. Backends that do
5635 not support this intrinisic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5636
5637</div>
5638
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5639<!-- _______________________________________________________________________ -->
5640<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5641 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5642</div>
5643
5644<div class="doc_text">
5645
5646<h5>Syntax:</h5>
5647<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5648 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5649</pre>
5650
5651<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5652<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5653 counter register (or similar low latency, high accuracy clocks) on those
5654 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5655 should map to RPCC. As the backing counters overflow quickly (on the order
5656 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5657
5658<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5659<p>When directly supported, reading the cycle counter should not modify any
5660 memory. Implementations are allowed to either return a application specific
5661 value or a system wide value. On backends without support, this is lowered
5662 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5663
5664</div>
5665
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5666<!-- ======================================================================= -->
5667<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5668 <a name="int_libc">Standard C Library Intrinsics</a>
5669</div>
5670
5671<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5672
5673<p>LLVM provides intrinsics for a few important standard C library functions.
5674 These intrinsics allow source-language front-ends to pass information about
5675 the alignment of the pointer arguments to the code generator, providing
5676 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5677
5678</div>
5679
5680<!-- _______________________________________________________________________ -->
5681<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5682 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5683</div>
5684
5685<div class="doc_text">
5686
5687<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5688<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5689 integer bit width. Not all targets support all bit widths however.</p>
5690
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5691<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5692 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5693 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5694 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5695 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5696 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5697 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5698 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5699 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5700</pre>
5701
5702<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5703<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5704 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5705
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5706<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5707 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5708
5709<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5710<p>The first argument is a pointer to the destination, the second is a pointer
5711 to the source. The third argument is an integer argument specifying the
5712 number of bytes to copy, and the fourth argument is the alignment of the
5713 source and destination locations.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5714
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5715<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5716 then the caller guarantees that both the source and destination pointers are
5717 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5718
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5719<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5720<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5721 source location to the destination location, which are not allowed to
5722 overlap. It copies "len" bytes of memory over. If the argument is known to
5723 be aligned to some boundary, this can be specified as the fourth argument,
5724 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5725
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5726</div>
5727
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5728<!-- _______________________________________________________________________ -->
5729<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5730 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5731</div>
5732
5733<div class="doc_text">
5734
5735<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5736<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5737 width. Not all targets support all bit widths however.</p>
5738
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5739<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5740 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5741 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5742 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5743 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5744 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5745 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5746 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5747 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5748</pre>
5749
5750<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5751<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5752 source location to the destination location. It is similar to the
5753 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5754 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5755
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5756<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5757 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5758
5759<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5760<p>The first argument is a pointer to the destination, the second is a pointer
5761 to the source. The third argument is an integer argument specifying the
5762 number of bytes to copy, and the fourth argument is the alignment of the
5763 source and destination locations.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5764
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5765<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5766 then the caller guarantees that the source and destination pointers are
5767 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5768
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5769<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5770<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5771 source location to the destination location, which may overlap. It copies
5772 "len" bytes of memory over. If the argument is known to be aligned to some
5773 boundary, this can be specified as the fourth argument, otherwise it should
5774 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5775
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5776</div>
5777
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5778<!-- _______________________________________________________________________ -->
5779<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5780 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5781</div>
5782
5783<div class="doc_text">
5784
5785<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5786<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5787 width. Not all targets support all bit widths however.</p>
5788
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5789<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5790 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5791 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5792 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5793 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5794 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5795 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5796 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5797 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5798</pre>
5799
5800<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5801<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5802 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5803
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5804<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5805 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5806
5807<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5808<p>The first argument is a pointer to the destination to fill, the second is the
5809 byte value to fill it with, the third argument is an integer argument
5810 specifying the number of bytes to fill, and the fourth argument is the known
5811 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5812
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5813<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5814 then the caller guarantees that the destination pointer is aligned to that
5815 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5816
5817<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5818<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5819 at the destination location. If the argument is known to be aligned to some
5820 boundary, this can be specified as the fourth argument, otherwise it should
5821 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5822
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5823</div>
5824
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5825<!-- _______________________________________________________________________ -->
5826<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5827 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5828</div>
5829
5830<div class="doc_text">
5831
5832<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5833<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5834 floating point or vector of floating point type. Not all targets support all
5835 types however.</p>
5836
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5837<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5838 declare float @llvm.sqrt.f32(float %Val)
5839 declare double @llvm.sqrt.f64(double %Val)
5840 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5841 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5842 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5843</pre>
5844
5845<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5846<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5847 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5848 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5849 behavior for negative numbers other than -0.0 (which allows for better
5850 optimization, because there is no need to worry about errno being
5851 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]5852
5853<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5854<p>The argument and return value are floating point numbers of the same
5855 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5856
5857<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5858<p>This function returns the sqrt of the specified operand if it is a
5859 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5860
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5861</div>
5862
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5863<!-- _______________________________________________________________________ -->
5864<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5865 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5866</div>
5867
5868<div class="doc_text">
5869
5870<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5871<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5872 floating point or vector of floating point type. Not all targets support all
5873 types however.</p>
5874
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5875<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5876 declare float @llvm.powi.f32(float %Val, i32 %power)
5877 declare double @llvm.powi.f64(double %Val, i32 %power)
5878 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5879 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5880 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5881</pre>
5882
5883<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5884<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5885 specified (positive or negative) power. The order of evaluation of
5886 multiplications is not defined. When a vector of floating point type is
5887 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5888
5889<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5890<p>The second argument is an integer power, and the first is a value to raise to
5891 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5892
5893<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5894<p>This function returns the first value raised to the second power with an
5895 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5896
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5897</div>
5898
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5899<!-- _______________________________________________________________________ -->
5900<div class="doc_subsubsection">
5901 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5902</div>
5903
5904<div class="doc_text">
5905
5906<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5907<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5908 floating point or vector of floating point type. Not all targets support all
5909 types however.</p>
5910
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5911<pre>
5912 declare float @llvm.sin.f32(float %Val)
5913 declare double @llvm.sin.f64(double %Val)
5914 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5915 declare fp128 @llvm.sin.f128(fp128 %Val)
5916 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5917</pre>
5918
5919<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5920<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5921
5922<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5923<p>The argument and return value are floating point numbers of the same
5924 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5925
5926<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5927<p>This function returns the sine of the specified operand, returning the same
5928 values as the libm <tt>sin</tt> functions would, and handles error conditions
5929 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5930
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5931</div>
5932
5933<!-- _______________________________________________________________________ -->
5934<div class="doc_subsubsection">
5935 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5936</div>
5937
5938<div class="doc_text">
5939
5940<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5941<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5942 floating point or vector of floating point type. Not all targets support all
5943 types however.</p>
5944
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5945<pre>
5946 declare float @llvm.cos.f32(float %Val)
5947 declare double @llvm.cos.f64(double %Val)
5948 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5949 declare fp128 @llvm.cos.f128(fp128 %Val)
5950 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5951</pre>
5952
5953<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5954<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5955
5956<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5957<p>The argument and return value are floating point numbers of the same
5958 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5959
5960<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5961<p>This function returns the cosine of the specified operand, returning the same
5962 values as the libm <tt>cos</tt> functions would, and handles error conditions
5963 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5964
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5965</div>
5966
5967<!-- _______________________________________________________________________ -->
5968<div class="doc_subsubsection">
5969 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5970</div>
5971
5972<div class="doc_text">
5973
5974<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5975<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5976 floating point or vector of floating point type. Not all targets support all
5977 types however.</p>
5978
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5979<pre>
5980 declare float @llvm.pow.f32(float %Val, float %Power)
5981 declare double @llvm.pow.f64(double %Val, double %Power)
5982 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5983 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5984 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5985</pre>
5986
5987<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5988<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5989 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5990
5991<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5992<p>The second argument is a floating point power, and the first is a value to
5993 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5994
5995<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5996<p>This function returns the first value raised to the second power, returning
5997 the same values as the libm <tt>pow</tt> functions would, and handles error
5998 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5999
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6000</div>
6001
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6002<!-- ======================================================================= -->
6003<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6004 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6005</div>
6006
6007<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6008
6009<p>LLVM provides intrinsics for a few important bit manipulation operations.
6010 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6011
6012</div>
6013
6014<!-- _______________________________________________________________________ -->
6015<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6016 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6017</div>
6018
6019<div class="doc_text">
6020
6021<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6022<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6023 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6024
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6025<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6026 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6027 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6028 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6029</pre>
6030
6031<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6032<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6033 values with an even number of bytes (positive multiple of 16 bits). These
6034 are useful for performing operations on data that is not in the target's
6035 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6036
6037<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6038<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6039 and low byte of the input i16 swapped. Similarly,
6040 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6041 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6042 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6043 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6044 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6045 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6046
6047</div>
6048
6049<!-- _______________________________________________________________________ -->
6050<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6051 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6052</div>
6053
6054<div class="doc_text">
6055
6056<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6057<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]6058 width. Not all targets support all bit widths however.</p>
6059
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6060<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6061 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6062 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6063 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6064 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6065 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6066</pre>
6067
6068<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6069<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6070 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6071
6072<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6073<p>The only argument is the value to be counted. The argument may be of any
6074 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6075
6076<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6077<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]6078
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6079</div>
6080
6081<!-- _______________________________________________________________________ -->
6082<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6083 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6084</div>
6085
6086<div class="doc_text">
6087
6088<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6089<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6090 integer bit width. Not all targets support all bit widths however.</p>
6091
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6092<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6093 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6094 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6095 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6096 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6097 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6098</pre>
6099
6100<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6101<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6102 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6103
6104<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6105<p>The only argument is the value to be counted. The argument may be of any
6106 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6107
6108<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6109<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6110 zeros in a variable. If the src == 0 then the result is the size in bits of
6111 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6112
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6113</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6114
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6115<!-- _______________________________________________________________________ -->
6116<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6117 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6118</div>
6119
6120<div class="doc_text">
6121
6122<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6123<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6124 integer bit width. Not all targets support all bit widths however.</p>
6125
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6126<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6127 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6128 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6129 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6130 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6131 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6132</pre>
6133
6134<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6135<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6136 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6137
6138<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6139<p>The only argument is the value to be counted. The argument may be of any
6140 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6141
6142<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6143<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6144 zeros in a variable. If the src == 0 then the result is the size in bits of
6145 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6146
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6147</div>
6148
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6149<!-- ======================================================================= -->
6150<div class="doc_subsection">
6151 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6152</div>
6153
6154<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6155
6156<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6157
6158</div>
6159
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6160<!-- _______________________________________________________________________ -->
6161<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6162 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6163</div>
6164
6165<div class="doc_text">
6166
6167<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6168<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]6169 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6170
6171<pre>
6172 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6173 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6174 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6175</pre>
6176
6177<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6178<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6179 a signed addition of the two arguments, and indicate whether an overflow
6180 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6181
6182<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6183<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]6184 be of integer types of any bit width, but they must have the same bit
6185 width. The second element of the result structure must be of
6186 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6187 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6188
6189<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6190<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6191 a signed addition of the two variables. They return a structure &mdash; the
6192 first element of which is the signed summation, and the second element of
6193 which is a bit specifying if the signed summation resulted in an
6194 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6195
6196<h5>Examples:</h5>
6197<pre>
6198 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6199 %sum = extractvalue {i32, i1} %res, 0
6200 %obit = extractvalue {i32, i1} %res, 1
6201 br i1 %obit, label %overflow, label %normal
6202</pre>
6203
6204</div>
6205
6206<!-- _______________________________________________________________________ -->
6207<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6208 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6209</div>
6210
6211<div class="doc_text">
6212
6213<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6214<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]6215 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6216
6217<pre>
6218 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6219 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6220 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6221</pre>
6222
6223<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6224<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6225 an unsigned addition of the two arguments, and indicate whether a carry
6226 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6227
6228<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6229<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]6230 be of integer types of any bit width, but they must have the same bit
6231 width. The second element of the result structure must be of
6232 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6233 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6234
6235<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6236<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6237 an unsigned addition of the two arguments. They return a structure &mdash;
6238 the first element of which is the sum, and the second element of which is a
6239 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6240
6241<h5>Examples:</h5>
6242<pre>
6243 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6244 %sum = extractvalue {i32, i1} %res, 0
6245 %obit = extractvalue {i32, i1} %res, 1
6246 br i1 %obit, label %carry, label %normal
6247</pre>
6248
6249</div>
6250
6251<!-- _______________________________________________________________________ -->
6252<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6253 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6254</div>
6255
6256<div class="doc_text">
6257
6258<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6259<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]6260 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6261
6262<pre>
6263 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6264 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6265 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6266</pre>
6267
6268<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6269<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6270 a signed subtraction of the two arguments, and indicate whether an overflow
6271 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6272
6273<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6274<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]6275 be of integer types of any bit width, but they must have the same bit
6276 width. The second element of the result structure must be of
6277 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6278 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6279
6280<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6281<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6282 a signed subtraction of the two arguments. They return a structure &mdash;
6283 the first element of which is the subtraction, and the second element of
6284 which is a bit specifying if the signed subtraction resulted in an
6285 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6286
6287<h5>Examples:</h5>
6288<pre>
6289 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6290 %sum = extractvalue {i32, i1} %res, 0
6291 %obit = extractvalue {i32, i1} %res, 1
6292 br i1 %obit, label %overflow, label %normal
6293</pre>
6294
6295</div>
6296
6297<!-- _______________________________________________________________________ -->
6298<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6299 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6300</div>
6301
6302<div class="doc_text">
6303
6304<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6305<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]6306 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6307
6308<pre>
6309 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6310 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6311 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6312</pre>
6313
6314<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6315<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6316 an unsigned subtraction of the two arguments, and indicate whether an
6317 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6318
6319<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6320<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]6321 be of integer types of any bit width, but they must have the same bit
6322 width. The second element of the result structure must be of
6323 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6324 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6325
6326<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6327<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6328 an unsigned subtraction of the two arguments. They return a structure &mdash;
6329 the first element of which is the subtraction, and the second element of
6330 which is a bit specifying if the unsigned subtraction resulted in an
6331 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6332
6333<h5>Examples:</h5>
6334<pre>
6335 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6336 %sum = extractvalue {i32, i1} %res, 0
6337 %obit = extractvalue {i32, i1} %res, 1
6338 br i1 %obit, label %overflow, label %normal
6339</pre>
6340
6341</div>
6342
6343<!-- _______________________________________________________________________ -->
6344<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6345 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6346</div>
6347
6348<div class="doc_text">
6349
6350<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6351<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]6352 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6353
6354<pre>
6355 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6356 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6357 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6358</pre>
6359
6360<h5>Overview:</h5>
6361
6362<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6363 a signed multiplication of the two arguments, and indicate whether an
6364 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6365
6366<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6367<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]6368 be of integer types of any bit width, but they must have the same bit
6369 width. The second element of the result structure must be of
6370 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6371 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6372
6373<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6374<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6375 a signed multiplication of the two arguments. They return a structure &mdash;
6376 the first element of which is the multiplication, and the second element of
6377 which is a bit specifying if the signed multiplication resulted in an
6378 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6379
6380<h5>Examples:</h5>
6381<pre>
6382 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6383 %sum = extractvalue {i32, i1} %res, 0
6384 %obit = extractvalue {i32, i1} %res, 1
6385 br i1 %obit, label %overflow, label %normal
6386</pre>
6387
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6388</div>
6389
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6390<!-- _______________________________________________________________________ -->
6391<div class="doc_subsubsection">
6392 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6393</div>
6394
6395<div class="doc_text">
6396
6397<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6398<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]6399 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6400
6401<pre>
6402 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6403 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6404 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6405</pre>
6406
6407<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6408<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6409 a unsigned multiplication of the two arguments, and indicate whether an
6410 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6411
6412<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6413<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]6414 be of integer types of any bit width, but they must have the same bit
6415 width. The second element of the result structure must be of
6416 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6417 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6418
6419<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6420<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6421 an unsigned multiplication of the two arguments. They return a structure
6422 &mdash; the first element of which is the multiplication, and the second
6423 element of which is a bit specifying if the unsigned multiplication resulted
6424 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6425
6426<h5>Examples:</h5>
6427<pre>
6428 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6429 %sum = extractvalue {i32, i1} %res, 0
6430 %obit = extractvalue {i32, i1} %res, 1
6431 br i1 %obit, label %overflow, label %normal
6432</pre>
6433
6434</div>
6435
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6436<!-- ======================================================================= -->
6437<div class="doc_subsection">
6438 <a name="int_debugger">Debugger Intrinsics</a>
6439</div>
6440
6441<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6442
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6443<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6444 prefix), are described in
6445 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6446 Level Debugging</a> document.</p>
6447
6448</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6449
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6450<!-- ======================================================================= -->
6451<div class="doc_subsection">
6452 <a name="int_eh">Exception Handling Intrinsics</a>
6453</div>
6454
6455<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6456
6457<p>The LLVM exception handling intrinsics (which all start with
6458 <tt>llvm.eh.</tt> prefix), are described in
6459 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6460 Handling</a> document.</p>
6461
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6462</div>
6463
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6464<!-- ======================================================================= -->
6465<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6466 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6467</div>
6468
6469<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6470
6471<p>This intrinsic makes it possible to excise one parameter, marked with
6472 the <tt>nest</tt> attribute, from a function. The result is a callable
6473 function pointer lacking the nest parameter - the caller does not need to
6474 provide a value for it. Instead, the value to use is stored in advance in a
6475 "trampoline", a block of memory usually allocated on the stack, which also
6476 contains code to splice the nest value into the argument list. This is used
6477 to implement the GCC nested function address extension.</p>
6478
6479<p>For example, if the function is
6480 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6481 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6482 follows:</p>
6483
6484<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6485<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6486 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6487 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6488 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6489 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6490</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6491</div>
6492
6493<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6494 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6495
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6496</div>
6497
6498<!-- _______________________________________________________________________ -->
6499<div class="doc_subsubsection">
6500 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6501</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6502
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6503<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6504
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6505<h5>Syntax:</h5>
6506<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6507 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]6508</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6509
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6510<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6511<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6512 function pointer suitable for executing it.</p>
6513
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6514<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6515<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6516 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6517 sufficiently aligned block of memory; this memory is written to by the
6518 intrinsic. Note that the size and the alignment are target-specific - LLVM
6519 currently provides no portable way of determining them, so a front-end that
6520 generates this intrinsic needs to have some target-specific knowledge.
6521 The <tt>func</tt> argument must hold a function bitcast to
6522 an <tt>i8*</tt>.</p>
6523
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6524<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6525<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6526 dependent code, turning it into a function. A pointer to this function is
6527 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6528 function pointer type</a> before being called. The new function's signature
6529 is the same as that of <tt>func</tt> with any arguments marked with
6530 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6531 is allowed, and it must be of pointer type. Calling the new function is
6532 equivalent to calling <tt>func</tt> with the same argument list, but
6533 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6534 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6535 by <tt>tramp</tt> is modified, then the effect of any later call to the
6536 returned function pointer is undefined.</p>
6537
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6538</div>
6539
6540<!-- ======================================================================= -->
6541<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6542 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6543</div>
6544
6545<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6546
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6547<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6548 hardware constructs for atomic operations and memory synchronization. This
6549 provides an interface to the hardware, not an interface to the programmer. It
6550 is aimed at a low enough level to allow any programming models or APIs
6551 (Application Programming Interfaces) which need atomic behaviors to map
6552 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6553 hardware provides a "universal IR" for source languages, it also provides a
6554 starting point for developing a "universal" atomic operation and
6555 synchronization IR.</p>
6556
6557<p>These do <em>not</em> form an API such as high-level threading libraries,
6558 software transaction memory systems, atomic primitives, and intrinsic
6559 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6560 application libraries. The hardware interface provided by LLVM should allow
6561 a clean implementation of all of these APIs and parallel programming models.
6562 No one model or paradigm should be selected above others unless the hardware
6563 itself ubiquitously does so.</p>
6564
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6565</div>
6566
6567<!-- _______________________________________________________________________ -->
6568<div class="doc_subsubsection">
6569 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6570</div>
6571<div class="doc_text">
6572<h5>Syntax:</h5>
6573<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6574 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]6575</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6576
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6577<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6578<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6579 specific pairs of memory access types.</p>
6580
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6581<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6582<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6583 The first four arguments enables a specific barrier as listed below. The
6584 fith argument specifies that the barrier applies to io or device or uncached
6585 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6586
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6587<ul>
6588 <li><tt>ll</tt>: load-load barrier</li>
6589 <li><tt>ls</tt>: load-store barrier</li>
6590 <li><tt>sl</tt>: store-load barrier</li>
6591 <li><tt>ss</tt>: store-store barrier</li>
6592 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6593</ul>
6594
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6595<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6596<p>This intrinsic causes the system to enforce some ordering constraints upon
6597 the loads and stores of the program. This barrier does not
6598 indicate <em>when</em> any events will occur, it only enforces
6599 an <em>order</em> in which they occur. For any of the specified pairs of load
6600 and store operations (f.ex. load-load, or store-load), all of the first
6601 operations preceding the barrier will complete before any of the second
6602 operations succeeding the barrier begin. Specifically the semantics for each
6603 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6604
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6605<ul>
6606 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6607 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6608 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6609 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6610 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6611 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6612 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6613 load after the barrier begins.</li>
6614</ul>
6615
6616<p>These semantics are applied with a logical "and" behavior when more than one
6617 is enabled in a single memory barrier intrinsic.</p>
6618
6619<p>Backends may implement stronger barriers than those requested when they do
6620 not support as fine grained a barrier as requested. Some architectures do
6621 not need all types of barriers and on such architectures, these become
6622 noops.</p>
6623
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6624<h5>Example:</h5>
6625<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6626%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6627%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6628 store i32 4, %ptr
6629
6630%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6631 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6632 <i>; guarantee the above finishes</i>
6633 store i32 8, %ptr <i>; before this begins</i>
6634</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6635
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6636</div>
6637
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6638<!-- _______________________________________________________________________ -->
6639<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6640 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6641</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6642
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6643<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6644
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6645<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6646<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6647 any integer bit width and for different address spaces. Not all targets
6648 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6649
6650<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6651 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6652 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6653 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6654 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]6655</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6656
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6657<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6658<p>This loads a value in memory and compares it to a given value. If they are
6659 equal, it stores a new value into the memory.</p>
6660
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6661<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6662<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6663 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6664 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6665 this integer type. While any bit width integer may be used, targets may only
6666 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6667
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6668<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6669<p>This entire intrinsic must be executed atomically. It first loads the value
6670 in memory pointed to by <tt>ptr</tt> and compares it with the
6671 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6672 memory. The loaded value is yielded in all cases. This provides the
6673 equivalent of an atomic compare-and-swap operation within the SSA
6674 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6675
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6676<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6677<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6678%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6679%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6680 store i32 4, %ptr
6681
6682%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6683%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6684 <i>; yields {i32}:result1 = 4</i>
6685%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6686%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6687
6688%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6689%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6690 <i>; yields {i32}:result2 = 8</i>
6691%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6692
6693%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6694</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6695
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6696</div>
6697
6698<!-- _______________________________________________________________________ -->
6699<div class="doc_subsubsection">
6700 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6701</div>
6702<div class="doc_text">
6703<h5>Syntax:</h5>
6704
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6705<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6706 integer bit width. Not all targets support all bit widths however.</p>
6707
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6708<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6709 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6710 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6711 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6712 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]6713</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6714
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6715<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6716<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6717 the value from memory. It then stores the value in <tt>val</tt> in the memory
6718 at <tt>ptr</tt>.</p>
6719
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6720<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6721<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6722 the <tt>val</tt> argument and the result must be integers of the same bit
6723 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6724 integer type. The targets may only lower integer representations they
6725 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6726
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6727<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6728<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6729 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6730 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6731
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6732<h5>Examples:</h5>
6733<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6734%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6735%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6736 store i32 4, %ptr
6737
6738%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6739%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6740 <i>; yields {i32}:result1 = 4</i>
6741%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6742%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6743
6744%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6745%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6746 <i>; yields {i32}:result2 = 8</i>
6747
6748%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6749%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6750</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6751
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6752</div>
6753
6754<!-- _______________________________________________________________________ -->
6755<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6756 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6757
6758</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6759
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6760<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6761
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6762<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6763<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6764 any integer bit width. Not all targets support all bit widths however.</p>
6765
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6766<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6767 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6768 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6769 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6770 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]6771</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6772
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6773<h5>Overview:</h5>
6774<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6775 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6776
6777<h5>Arguments:</h5>
6778<p>The intrinsic takes two arguments, the first a pointer to an integer value
6779 and the second an integer value. The result is also an integer value. These
6780 integer types can have any bit width, but they must all have the same bit
6781 width. The targets may only lower integer representations they support.</p>
6782
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6783<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6784<p>This intrinsic does a series of operations atomically. It first loads the
6785 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6786 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]6787
6788<h5>Examples:</h5>
6789<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6790%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6791%ptr = bitcast i8* %mallocP to i32*
6792 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6793%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6794 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6795%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6796 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6797%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6798 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6799%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6800</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6801
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6802</div>
6803
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6804<!-- _______________________________________________________________________ -->
6805<div class="doc_subsubsection">
6806 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6807
6808</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6809
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6810<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6811
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6812<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6813<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6814 any integer bit width and for different address spaces. Not all targets
6815 support all bit widths however.</p>
6816
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6817<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6818 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6819 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6820 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6821 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]6822</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6823
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6824<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6825<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6826 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6827
6828<h5>Arguments:</h5>
6829<p>The intrinsic takes two arguments, the first a pointer to an integer value
6830 and the second an integer value. The result is also an integer value. These
6831 integer types can have any bit width, but they must all have the same bit
6832 width. The targets may only lower integer representations they support.</p>
6833
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6834<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6835<p>This intrinsic does a series of operations atomically. It first loads the
6836 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6837 result to <tt>ptr</tt>. It yields the original value stored
6838 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6839
6840<h5>Examples:</h5>
6841<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6842%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6843%ptr = bitcast i8* %mallocP to i32*
6844 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6845%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6846 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6847%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6848 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6849%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6850 <i>; yields {i32}:result3 = 2</i>
6851%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6852</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6853
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6854</div>
6855
6856<!-- _______________________________________________________________________ -->
6857<div class="doc_subsubsection">
6858 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6859 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6860 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6861 <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]6862</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6863
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6864<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6865
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6866<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6867<p>These are overloaded intrinsics. You can
6868 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6869 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6870 bit width and for different address spaces. Not all targets support all bit
6871 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6872
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6873<pre>
6874 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6875 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6876 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6877 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]6878</pre>
6879
6880<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6881 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6882 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6883 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6884 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]6885</pre>
6886
6887<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6888 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6889 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6890 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6891 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]6892</pre>
6893
6894<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6895 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6896 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6897 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6898 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]6899</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6900
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6901<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6902<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6903 the value stored in memory at <tt>ptr</tt>. It yields the original value
6904 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6905
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6906<h5>Arguments:</h5>
6907<p>These intrinsics take two arguments, the first a pointer to an integer value
6908 and the second an integer value. The result is also an integer value. These
6909 integer types can have any bit width, but they must all have the same bit
6910 width. The targets may only lower integer representations they support.</p>
6911
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6912<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6913<p>These intrinsics does a series of operations atomically. They first load the
6914 value stored at <tt>ptr</tt>. They then do the bitwise
6915 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6916 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6917
6918<h5>Examples:</h5>
6919<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6920%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6921%ptr = bitcast i8* %mallocP to i32*
6922 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6923%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6924 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6925%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6926 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6927%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6928 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6929%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6930 <i>; yields {i32}:result3 = FF</i>
6931%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6932</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6933
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6934</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6935
6936<!-- _______________________________________________________________________ -->
6937<div class="doc_subsubsection">
6938 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6939 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6940 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6941 <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]6942</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6943
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6944<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6945
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6946<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6947<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6948 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6949 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6950 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6951
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6952<pre>
6953 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6954 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6955 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6956 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]6957</pre>
6958
6959<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6960 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6961 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6962 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6963 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]6964</pre>
6965
6966<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6967 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6968 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6969 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6970 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]6971</pre>
6972
6973<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6974 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6975 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6976 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6977 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]6978</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6979
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6980<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6981<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6982 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6983 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6984
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6985<h5>Arguments:</h5>
6986<p>These intrinsics take two arguments, the first a pointer to an integer value
6987 and the second an integer value. The result is also an integer value. These
6988 integer types can have any bit width, but they must all have the same bit
6989 width. The targets may only lower integer representations they support.</p>
6990
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6991<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6992<p>These intrinsics does a series of operations atomically. They first load the
6993 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6994 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6995 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6996
6997<h5>Examples:</h5>
6998<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6999%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7000%ptr = bitcast i8* %mallocP to i32*
7001 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7002%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7003 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7004%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7005 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7006%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7007 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7008%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7009 <i>; yields {i32}:result3 = 8</i>
7010%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7011</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7012
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7013</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7014
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7015
7016<!-- ======================================================================= -->
7017<div class="doc_subsection">
7018 <a name="int_memorymarkers">Memory Use Markers</a>
7019</div>
7020
7021<div class="doc_text">
7022
7023<p>This class of intrinsics exists to information about the lifetime of memory
7024 objects and ranges where variables are immutable.</p>
7025
7026</div>
7027
7028<!-- _______________________________________________________________________ -->
7029<div class="doc_subsubsection">
7030 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7031</div>
7032
7033<div class="doc_text">
7034
7035<h5>Syntax:</h5>
7036<pre>
7037 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7038</pre>
7039
7040<h5>Overview:</h5>
7041<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7042 object's lifetime.</p>
7043
7044<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7045<p>The first argument is a constant integer representing the size of the
7046 object, or -1 if it is variable sized. The second argument is a pointer to
7047 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7048
7049<h5>Semantics:</h5>
7050<p>This intrinsic indicates that before this point in the code, the value of the
7051 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]7052 never be used and has an undefined value. A load from the pointer that
7053 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7054 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7055
7056</div>
7057
7058<!-- _______________________________________________________________________ -->
7059<div class="doc_subsubsection">
7060 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7061</div>
7062
7063<div class="doc_text">
7064
7065<h5>Syntax:</h5>
7066<pre>
7067 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7068</pre>
7069
7070<h5>Overview:</h5>
7071<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7072 object's lifetime.</p>
7073
7074<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7075<p>The first argument is a constant integer representing the size of the
7076 object, or -1 if it is variable sized. The second argument is a pointer to
7077 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7078
7079<h5>Semantics:</h5>
7080<p>This intrinsic indicates that after this point in the code, the value of the
7081 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7082 never be used and has an undefined value. Any stores into the memory object
7083 following this intrinsic may be removed as dead.
7084
7085</div>
7086
7087<!-- _______________________________________________________________________ -->
7088<div class="doc_subsubsection">
7089 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7090</div>
7091
7092<div class="doc_text">
7093
7094<h5>Syntax:</h5>
7095<pre>
7096 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7097</pre>
7098
7099<h5>Overview:</h5>
7100<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7101 a memory object will not change.</p>
7102
7103<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7104<p>The first argument is a constant integer representing the size of the
7105 object, or -1 if it is variable sized. The second argument is a pointer to
7106 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7107
7108<h5>Semantics:</h5>
7109<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7110 the return value, the referenced memory location is constant and
7111 unchanging.</p>
7112
7113</div>
7114
7115<!-- _______________________________________________________________________ -->
7116<div class="doc_subsubsection">
7117 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7118</div>
7119
7120<div class="doc_text">
7121
7122<h5>Syntax:</h5>
7123<pre>
7124 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7125</pre>
7126
7127<h5>Overview:</h5>
7128<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7129 a memory object are mutable.</p>
7130
7131<h5>Arguments:</h5>
7132<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7133 The second argument is a constant integer representing the size of the
7134 object, or -1 if it is variable sized and the third argument is a pointer
7135 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7136
7137<h5>Semantics:</h5>
7138<p>This intrinsic indicates that the memory is mutable again.</p>
7139
7140</div>
7141
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7142<!-- ======================================================================= -->
7143<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7144 <a name="int_general">General Intrinsics</a>
7145</div>
7146
7147<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7148
7149<p>This class of intrinsics is designed to be generic and has no specific
7150 purpose.</p>
7151
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7152</div>
7153
7154<!-- _______________________________________________________________________ -->
7155<div class="doc_subsubsection">
7156 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7157</div>
7158
7159<div class="doc_text">
7160
7161<h5>Syntax:</h5>
7162<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7163 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]7164</pre>
7165
7166<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7167<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7168
7169<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7170<p>The first argument is a pointer to a value, the second is a pointer to a
7171 global string, the third is a pointer to a global string which is the source
7172 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7173
7174<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7175<p>This intrinsic allows annotation of local variables with arbitrary strings.
7176 This can be useful for special purpose optimizations that want to look for
7177 these annotations. These have no other defined use, they are ignored by code
7178 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7179
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7180</div>
7181
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7182<!-- _______________________________________________________________________ -->
7183<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7184 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7185</div>
7186
7187<div class="doc_text">
7188
7189<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7190<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7191 any integer bit width.</p>
7192
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7193<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7194 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7195 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7196 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7197 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7198 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]7199</pre>
7200
7201<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7202<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7203
7204<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7205<p>The first argument is an integer value (result of some expression), the
7206 second is a pointer to a global string, the third is a pointer to a global
7207 string which is the source file name, and the last argument is the line
7208 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7209
7210<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7211<p>This intrinsic allows annotations to be put on arbitrary expressions with
7212 arbitrary strings. This can be useful for special purpose optimizations that
7213 want to look for these annotations. These have no other defined use, they
7214 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7215
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7216</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7217
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7218<!-- _______________________________________________________________________ -->
7219<div class="doc_subsubsection">
7220 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7221</div>
7222
7223<div class="doc_text">
7224
7225<h5>Syntax:</h5>
7226<pre>
7227 declare void @llvm.trap()
7228</pre>
7229
7230<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7231<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7232
7233<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7234<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7235
7236<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7237<p>This intrinsics is lowered to the target dependent trap instruction. If the
7238 target does not have a trap instruction, this intrinsic will be lowered to
7239 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7240
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7241</div>
7242
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7243<!-- _______________________________________________________________________ -->
7244<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7245 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7246</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7247
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7248<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7249
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7250<h5>Syntax:</h5>
7251<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7252 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7253</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7254
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7255<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7256<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7257 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7258 ensure that it is placed on the stack before local variables.</p>
7259
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7260<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7261<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7262 arguments. The first argument is the value loaded from the stack
7263 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7264 that has enough space to hold the value of the guard.</p>
7265
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7266<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7267<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7268 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7269 stack. This is to ensure that if a local variable on the stack is
7270 overwritten, it will destroy the value of the guard. When the function exits,
7271 the guard on the stack is checked against the original guard. If they're
7272 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7273 function.</p>
7274
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7275</div>
7276
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7277<!-- _______________________________________________________________________ -->
7278<div class="doc_subsubsection">
7279 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7280</div>
7281
7282<div class="doc_text">
7283
7284<h5>Syntax:</h5>
7285<pre>
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7286 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7287 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7288</pre>
7289
7290<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7291<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7292 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7293 operation like memcpy will either overflow a buffer that corresponds to
7294 an object, or b) to determine that a runtime check for overflow isn't
7295 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7296 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7297
7298<h5>Arguments:</h5>
7299<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7300 argument is a pointer to or into the <tt>object</tt>. The second argument
7301 is a boolean 0 or 1. This argument determines whether you want the
7302 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7303 1, variables are not allowed.</p>
7304
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7305<h5>Semantics:</h5>
7306<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7307 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7308 (depending on the <tt>type</tt> argument if the size cannot be determined
7309 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7310
7311</div>
7312
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7313<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7314<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7315<address>
7316 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7317 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7318 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7319 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]7320
7321 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7322 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7323 Last modified: $Date$
7324</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7325
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7326</body>
7327</html>