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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 65687f76c0732e04eb3dac2164e88ff269615111 / . / 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">
8 <meta name="description"
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>
Robert Bocchino7b81c752006-02-17 21:18:08 +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>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]294 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]295 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]296 </ol>
297 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]298</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]299
300<div class="doc_author">
301 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
302 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]303</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]304
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]305<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]306<div class="doc_section"> <a name="abstract">Abstract </a></div>
307<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]308
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]309<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]310
311<p>This document is a reference manual for the LLVM assembly language. LLVM is
312 a Static Single Assignment (SSA) based representation that provides type
313 safety, low-level operations, flexibility, and the capability of representing
314 'all' high-level languages cleanly. It is the common code representation
315 used throughout all phases of the LLVM compilation strategy.</p>
316
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]317</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]318
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]319<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]320<div class="doc_section"> <a name="introduction">Introduction</a> </div>
321<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]322
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]323<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]324
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]325<p>The LLVM code representation is designed to be used in three different forms:
326 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
327 for fast loading by a Just-In-Time compiler), and as a human readable
328 assembly language representation. This allows LLVM to provide a powerful
329 intermediate representation for efficient compiler transformations and
330 analysis, while providing a natural means to debug and visualize the
331 transformations. The three different forms of LLVM are all equivalent. This
332 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]333
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]334<p>The LLVM representation aims to be light-weight and low-level while being
335 expressive, typed, and extensible at the same time. It aims to be a
336 "universal IR" of sorts, by being at a low enough level that high-level ideas
337 may be cleanly mapped to it (similar to how microprocessors are "universal
338 IR's", allowing many source languages to be mapped to them). By providing
339 type information, LLVM can be used as the target of optimizations: for
340 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]341 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]342 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]343
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]344</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]345
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]346<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]347<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]348
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]349<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]351<p>It is important to note that this document describes 'well formed' LLVM
352 assembly language. There is a difference between what the parser accepts and
353 what is considered 'well formed'. For example, the following instruction is
354 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]355
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]356<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]357<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]358%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]359</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]360</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]362<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
363 LLVM infrastructure provides a verification pass that may be used to verify
364 that an LLVM module is well formed. This pass is automatically run by the
365 parser after parsing input assembly and by the optimizer before it outputs
366 bitcode. The violations pointed out by the verifier pass indicate bugs in
367 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]368
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]369</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]370
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]371<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]373<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]374<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]375<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]376
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]377<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]378
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]379<p>LLVM identifiers come in two basic types: global and local. Global
380 identifiers (functions, global variables) begin with the <tt>'@'</tt>
381 character. Local identifiers (register names, types) begin with
382 the <tt>'%'</tt> character. Additionally, there are three different formats
383 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]384
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]385<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]386 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]387 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
388 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
389 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
390 other characters in their names can be surrounded with quotes. Special
391 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
392 ASCII code for the character in hexadecimal. In this way, any character
393 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]394
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]395 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]396 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]397
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]398 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]399 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]400</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]401
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]402<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]403 don't need to worry about name clashes with reserved words, and the set of
404 reserved words may be expanded in the future without penalty. Additionally,
405 unnamed identifiers allow a compiler to quickly come up with a temporary
406 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]407
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]408<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]409 languages. There are keywords for different opcodes
410 ('<tt><a href="#i_add">add</a></tt>',
411 '<tt><a href="#i_bitcast">bitcast</a></tt>',
412 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
413 ('<tt><a href="#t_void">void</a></tt>',
414 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
415 reserved words cannot conflict with variable names, because none of them
416 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
418<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]420
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]421<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]422
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]423<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]425%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]426</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]427</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]428
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]429<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]430
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]431<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]433%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]435</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]439<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440<pre>
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]441%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
442%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]443%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]445</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]447<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
448 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]450<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]452 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453
454 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]455 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]457 <li>Unnamed temporaries are numbered sequentially</li>
458</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]460<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]461 demonstrating instructions, we will follow an instruction with a comment that
462 defines the type and name of value produced. Comments are shown in italic
463 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]464
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]465</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]466
467<!-- *********************************************************************** -->
468<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
469<!-- *********************************************************************** -->
470
471<!-- ======================================================================= -->
472<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
473</div>
474
475<div class="doc_text">
476
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]477<p>LLVM programs are composed of "Module"s, each of which is a translation unit
478 of the input programs. Each module consists of functions, global variables,
479 and symbol table entries. Modules may be combined together with the LLVM
480 linker, which merges function (and global variable) definitions, resolves
481 forward declarations, and merges symbol table entries. Here is an example of
482 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]483
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]484<div class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]485<pre>
486<i>; Declare the string constant as a global constant.</i>
487<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]488
489<i>; External declaration of the puts function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]490<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]491
492<i>; Definition of main function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]493define i32 @main() { <i>; i32()* </i>
494 <i>; Convert [13 x i8]* to i8 *...</i>
495 %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]496
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]497 <i>; Call puts function to write out the string to stdout.</i>
498 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
499 <a href="#i_ret">ret</a> i32 0<br>}<br>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]500</pre>
501</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]502
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]503<p>This example is made up of a <a href="#globalvars">global variable</a> named
504 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
505 a <a href="#functionstructure">function definition</a> for
506 "<tt>main</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]507
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]508<p>In general, a module is made up of a list of global values, where both
509 functions and global variables are global values. Global values are
510 represented by a pointer to a memory location (in this case, a pointer to an
511 array of char, and a pointer to a function), and have one of the
512 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]513
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]514</div>
515
516<!-- ======================================================================= -->
517<div class="doc_subsection">
518 <a name="linkage">Linkage Types</a>
519</div>
520
521<div class="doc_text">
522
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]523<p>All Global Variables and Functions have one of the following types of
524 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]525
526<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]527 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]528 <dd>Global values with private linkage are only directly accessible by objects
529 in the current module. In particular, linking code into a module with an
530 private global value may cause the private to be renamed as necessary to
531 avoid collisions. Because the symbol is private to the module, all
532 references can be updated. This doesn't show up in any symbol table in the
533 object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]534
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]535 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]536 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere1eaf912009-08-24 04:32:16 +0000[diff] [blame]537 removed by the linker after evaluation. Note that (unlike private
538 symbols) linker_private symbols are subject to coalescing by the linker:
539 weak symbols get merged and redefinitions are rejected. However, unlike
540 normal strong symbols, they are removed by the linker from the final
541 linked image (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]542
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]544 <dd>Similar to private, but the value shows as a local symbol
545 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
546 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]547
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]549 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]550 into the object file corresponding to the LLVM module. They exist to
551 allow inlining and other optimizations to take place given knowledge of
552 the definition of the global, which is known to be somewhere outside the
553 module. Globals with <tt>available_externally</tt> linkage are allowed to
554 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
555 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]556
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]557 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]558 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]559 the same name when linkage occurs. This is typically used to implement
560 inline functions, templates, or other code which must be generated in each
561 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
562 allowed to be discarded.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]563
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]565 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
566 <tt>linkonce</tt> linkage, except that unreferenced globals with
567 <tt>weak</tt> linkage may not be discarded. This is used for globals that
568 are declared "weak" in C source code.</dd>
569
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]571 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
572 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
573 global scope.
574 Symbols with "<tt>common</tt>" linkage are merged in the same way as
575 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]576 <tt>common</tt> symbols may not have an explicit section,
577 must have a zero initializer, and may not be marked '<a
578 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
579 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]580
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]581
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]582 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]583 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]584 pointer to array type. When two global variables with appending linkage
585 are linked together, the two global arrays are appended together. This is
586 the LLVM, typesafe, equivalent of having the system linker append together
587 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]588
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]590 <dd>The semantics of this linkage follow the ELF object file model: the symbol
591 is weak until linked, if not linked, the symbol becomes null instead of
592 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]593
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]594 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
595 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]596 <dd>Some languages allow differing globals to be merged, such as two functions
597 with different semantics. Other languages, such as <tt>C++</tt>, ensure
598 that only equivalent globals are ever merged (the "one definition rule" -
599 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
600 and <tt>weak_odr</tt> linkage types to indicate that the global will only
601 be merged with equivalent globals. These linkage types are otherwise the
602 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]603
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]605 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]606 visible, meaning that it participates in linkage and can be used to
607 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]608</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]609
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]610<p>The next two types of linkage are targeted for Microsoft Windows platform
611 only. They are designed to support importing (exporting) symbols from (to)
612 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]613
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]614<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]616 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]617 or variable via a global pointer to a pointer that is set up by the DLL
618 exporting the symbol. On Microsoft Windows targets, the pointer name is
619 formed by combining <code>__imp_</code> and the function or variable
620 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]621
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]623 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 pointer to a pointer in a DLL, so that it can be referenced with the
625 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
626 name is formed by combining <code>__imp_</code> and the function or
627 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]628</dl>
629
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]630<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
631 another module defined a "<tt>.LC0</tt>" variable and was linked with this
632 one, one of the two would be renamed, preventing a collision. Since
633 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
634 declarations), they are accessible outside of the current module.</p>
635
636<p>It is illegal for a function <i>declaration</i> to have any linkage type
637 other than "externally visible", <tt>dllimport</tt>
638 or <tt>extern_weak</tt>.</p>
639
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]640<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]641 or <tt>weak_odr</tt> linkages.</p>
642
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]643</div>
644
645<!-- ======================================================================= -->
646<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]647 <a name="callingconv">Calling Conventions</a>
648</div>
649
650<div class="doc_text">
651
652<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]653 and <a href="#i_invoke">invokes</a> can all have an optional calling
654 convention specified for the call. The calling convention of any pair of
655 dynamic caller/callee must match, or the behavior of the program is
656 undefined. The following calling conventions are supported by LLVM, and more
657 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]658
659<dl>
660 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]661 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]662 specified) matches the target C calling conventions. This calling
663 convention supports varargs function calls and tolerates some mismatch in
664 the declared prototype and implemented declaration of the function (as
665 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]666
667 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]668 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]669 (e.g. by passing things in registers). This calling convention allows the
670 target to use whatever tricks it wants to produce fast code for the
671 target, without having to conform to an externally specified ABI
672 (Application Binary Interface). Implementations of this convention should
673 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
674 optimization</a> to be supported. This calling convention does not
675 support varargs and requires the prototype of all callees to exactly match
676 the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]677
678 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]679 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]680 as possible under the assumption that the call is not commonly executed.
681 As such, these calls often preserve all registers so that the call does
682 not break any live ranges in the caller side. This calling convention
683 does not support varargs and requires the prototype of all callees to
684 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]685
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]686 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]687 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]688 target-specific calling conventions to be used. Target specific calling
689 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]690</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]691
692<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]693 support Pascal conventions or any other well-known target-independent
694 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695
696</div>
697
698<!-- ======================================================================= -->
699<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]700 <a name="visibility">Visibility Styles</a>
701</div>
702
703<div class="doc_text">
704
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]705<p>All Global Variables and Functions have one of the following visibility
706 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]707
708<dl>
709 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]710 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]711 that the declaration is visible to other modules and, in shared libraries,
712 means that the declared entity may be overridden. On Darwin, default
713 visibility means that the declaration is visible to other modules. Default
714 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]715
716 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]717 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]718 object if they are in the same shared object. Usually, hidden visibility
719 indicates that the symbol will not be placed into the dynamic symbol
720 table, so no other module (executable or shared library) can reference it
721 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]722
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]723 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]724 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]725 the dynamic symbol table, but that references within the defining module
726 will bind to the local symbol. That is, the symbol cannot be overridden by
727 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]728</dl>
729
730</div>
731
732<!-- ======================================================================= -->
733<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]734 <a name="namedtypes">Named Types</a>
735</div>
736
737<div class="doc_text">
738
739<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]740 it easier to read the IR and make the IR more condensed (particularly when
741 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]742
743<div class="doc_code">
744<pre>
745%mytype = type { %mytype*, i32 }
746</pre>
747</div>
748
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]749<p>You may give a name to any <a href="#typesystem">type</a> except
750 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
751 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]752
753<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]754 and that you can therefore specify multiple names for the same type. This
755 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
756 uses structural typing, the name is not part of the type. When printing out
757 LLVM IR, the printer will pick <em>one name</em> to render all types of a
758 particular shape. This means that if you have code where two different
759 source types end up having the same LLVM type, that the dumper will sometimes
760 print the "wrong" or unexpected type. This is an important design point and
761 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]762
763</div>
764
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]765<!-- ======================================================================= -->
766<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]767 <a name="globalvars">Global Variables</a>
768</div>
769
770<div class="doc_text">
771
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]772<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]773 instead of run-time. Global variables may optionally be initialized, may
774 have an explicit section to be placed in, and may have an optional explicit
775 alignment specified. A variable may be defined as "thread_local", which
776 means that it will not be shared by threads (each thread will have a
777 separated copy of the variable). A variable may be defined as a global
778 "constant," which indicates that the contents of the variable
779 will <b>never</b> be modified (enabling better optimization, allowing the
780 global data to be placed in the read-only section of an executable, etc).
781 Note that variables that need runtime initialization cannot be marked
782 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]783
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]784<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
785 constant, even if the final definition of the global is not. This capability
786 can be used to enable slightly better optimization of the program, but
787 requires the language definition to guarantee that optimizations based on the
788 'constantness' are valid for the translation units that do not include the
789 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]790
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]791<p>As SSA values, global variables define pointer values that are in scope
792 (i.e. they dominate) all basic blocks in the program. Global variables
793 always define a pointer to their "content" type because they describe a
794 region of memory, and all memory objects in LLVM are accessed through
795 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]796
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]797<p>A global variable may be declared to reside in a target-specific numbered
798 address space. For targets that support them, address spaces may affect how
799 optimizations are performed and/or what target instructions are used to
800 access the variable. The default address space is zero. The address space
801 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]802
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]803<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]804 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]805
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]806<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]807 the alignment is set to zero, the alignment of the global is set by the
808 target to whatever it feels convenient. If an explicit alignment is
809 specified, the global is forced to have at least that much alignment. All
810 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]811
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]812<p>For example, the following defines a global in a numbered address space with
813 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]814
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]815<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]816<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]817@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]818</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]819</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]820
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]821</div>
822
823
824<!-- ======================================================================= -->
825<div class="doc_subsection">
826 <a name="functionstructure">Functions</a>
827</div>
828
829<div class="doc_text">
830
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]831<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
832 optional <a href="#linkage">linkage type</a>, an optional
833 <a href="#visibility">visibility style</a>, an optional
834 <a href="#callingconv">calling convention</a>, a return type, an optional
835 <a href="#paramattrs">parameter attribute</a> for the return type, a function
836 name, a (possibly empty) argument list (each with optional
837 <a href="#paramattrs">parameter attributes</a>), optional
838 <a href="#fnattrs">function attributes</a>, an optional section, an optional
839 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
840 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]841
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]842<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
843 optional <a href="#linkage">linkage type</a>, an optional
844 <a href="#visibility">visibility style</a>, an optional
845 <a href="#callingconv">calling convention</a>, a return type, an optional
846 <a href="#paramattrs">parameter attribute</a> for the return type, a function
847 name, a possibly empty list of arguments, an optional alignment, and an
848 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]849
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]850<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]851 (Control Flow Graph) for the function. Each basic block may optionally start
852 with a label (giving the basic block a symbol table entry), contains a list
853 of instructions, and ends with a <a href="#terminators">terminator</a>
854 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]855
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]856<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]857 executed on entrance to the function, and it is not allowed to have
858 predecessor basic blocks (i.e. there can not be any branches to the entry
859 block of a function). Because the block can have no predecessors, it also
860 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]861
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]862<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]864
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]865<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]866 the alignment is set to zero, the alignment of the function is set by the
867 target to whatever it feels convenient. If an explicit alignment is
868 specified, the function is forced to have at least that much alignment. All
869 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]870
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]871<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]872<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]873<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]874define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]875 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
876 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
877 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
878 [<a href="#gc">gc</a>] { ... }
879</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]880</div>
881
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]882</div>
883
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]884<!-- ======================================================================= -->
885<div class="doc_subsection">
886 <a name="aliasstructure">Aliases</a>
887</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]888
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]889<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]890
891<p>Aliases act as "second name" for the aliasee value (which can be either
892 function, global variable, another alias or bitcast of global value). Aliases
893 may have an optional <a href="#linkage">linkage type</a>, and an
894 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]895
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]896<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]897<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]898<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]899@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]900</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]901</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]902
903</div>
904
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]905<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]906<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]907
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]908<div class="doc_text">
909
910<p>The return type and each parameter of a function type may have a set of
911 <i>parameter attributes</i> associated with them. Parameter attributes are
912 used to communicate additional information about the result or parameters of
913 a function. Parameter attributes are considered to be part of the function,
914 not of the function type, so functions with different parameter attributes
915 can have the same function type.</p>
916
917<p>Parameter attributes are simple keywords that follow the type specified. If
918 multiple parameter attributes are needed, they are space separated. For
919 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]920
921<div class="doc_code">
922<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]923declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]924declare i32 @atoi(i8 zeroext)
925declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]926</pre>
927</div>
928
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]929<p>Note that any attributes for the function result (<tt>nounwind</tt>,
930 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]931
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]932<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]933
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]934<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]935 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]936 <dd>This indicates to the code generator that the parameter or return value
937 should be zero-extended to a 32-bit value by the caller (for a parameter)
938 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]939
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]940 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]941 <dd>This indicates to the code generator that the parameter or return value
942 should be sign-extended to a 32-bit value by the caller (for a parameter)
943 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]944
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]945 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]946 <dd>This indicates that this parameter or return value should be treated in a
947 special target-dependent fashion during while emitting code for a function
948 call or return (usually, by putting it in a register as opposed to memory,
949 though some targets use it to distinguish between two different kinds of
950 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]951
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]952 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]953 <dd>This indicates that the pointer parameter should really be passed by value
954 to the function. The attribute implies that a hidden copy of the pointee
955 is made between the caller and the callee, so the callee is unable to
956 modify the value in the callee. This attribute is only valid on LLVM
957 pointer arguments. It is generally used to pass structs and arrays by
958 value, but is also valid on pointers to scalars. The copy is considered
959 to belong to the caller not the callee (for example,
960 <tt><a href="#readonly">readonly</a></tt> functions should not write to
961 <tt>byval</tt> parameters). This is not a valid attribute for return
962 values. The byval attribute also supports specifying an alignment with
963 the align attribute. This has a target-specific effect on the code
964 generator that usually indicates a desired alignment for the synthesized
965 stack slot.</dd>
966
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]967 <dt><tt><b>sret</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]968 <dd>This indicates that the pointer parameter specifies the address of a
969 structure that is the return value of the function in the source program.
970 This pointer must be guaranteed by the caller to be valid: loads and
971 stores to the structure may be assumed by the callee to not to trap. This
972 may only be applied to the first parameter. This is not a valid attribute
973 for return values. </dd>
974
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]975 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]976 <dd>This indicates that the pointer does not alias any global or any other
977 parameter. The caller is responsible for ensuring that this is the
978 case. On a function return value, <tt>noalias</tt> additionally indicates
979 that the pointer does not alias any other pointers visible to the
980 caller. For further details, please see the discussion of the NoAlias
981 response in
982 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
983 analysis</a>.</dd>
984
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]985 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]986 <dd>This indicates that the callee does not make any copies of the pointer
987 that outlive the callee itself. This is not a valid attribute for return
988 values.</dd>
989
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]990 <dt><tt><b>nest</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]991 <dd>This indicates that the pointer parameter can be excised using the
992 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
993 attribute for return values.</dd>
994</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]995
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]996</div>
997
998<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]999<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1000 <a name="gc">Garbage Collector Names</a>
1001</div>
1002
1003<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005<p>Each function may specify a garbage collector name, which is simply a
1006 string:</p>
1007
1008<div class="doc_code">
1009<pre>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1010define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1011</pre>
1012</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1013
1014<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1015 collector which will cause the compiler to alter its output in order to
1016 support the named garbage collection algorithm.</p>
1017
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1018</div>
1019
1020<!-- ======================================================================= -->
1021<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1022 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1023</div>
1024
1025<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1026
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1027<p>Function attributes are set to communicate additional information about a
1028 function. Function attributes are considered to be part of the function, not
1029 of the function type, so functions with different parameter attributes can
1030 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1031
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1032<p>Function attributes are simple keywords that follow the type specified. If
1033 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1034
1035<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1036<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1037define void @f() noinline { ... }
1038define void @f() alwaysinline { ... }
1039define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1040define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1041</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1042</div>
1043
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1044<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1045 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1046 <dd>This attribute indicates that the inliner should attempt to inline this
1047 function into callers whenever possible, ignoring any active inlining size
1048 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1049
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1050 <dt><tt><b>inlinehint</b></tt></dt>
Dale Johannesende86d472009-08-26 01:08:21 +0000[diff] [blame]1051 <dd>This attribute indicates that the source code contained a hint that inlining
1052 this function is desirable (such as the "inline" keyword in C/C++). It
1053 is just a hint; it imposes no requirements on the inliner.</dd>
1054
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1055 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This attribute indicates that the inliner should never inline this
1057 function in any situation. This attribute may not be used together with
1058 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1059
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1060 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This attribute suggests that optimization passes and code generator passes
1062 make choices that keep the code size of this function low, and otherwise
1063 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1064
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1065 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This function attribute indicates that the function never returns
1067 normally. This produces undefined behavior at runtime if the function
1068 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1069
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1070 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This function attribute indicates that the function never returns with an
1072 unwind or exceptional control flow. If the function does unwind, its
1073 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1074
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1075 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1076 <dd>This attribute indicates that the function computes its result (or decides
1077 to unwind an exception) based strictly on its arguments, without
1078 dereferencing any pointer arguments or otherwise accessing any mutable
1079 state (e.g. memory, control registers, etc) visible to caller functions.
1080 It does not write through any pointer arguments
1081 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1082 changes any state visible to callers. This means that it cannot unwind
1083 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1084 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1085
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1086 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1087 <dd>This attribute indicates that the function does not write through any
1088 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1089 arguments) or otherwise modify any state (e.g. memory, control registers,
1090 etc) visible to caller functions. It may dereference pointer arguments
1091 and read state that may be set in the caller. A readonly function always
1092 returns the same value (or unwinds an exception identically) when called
1093 with the same set of arguments and global state. It cannot unwind an
1094 exception by calling the <tt>C++</tt> exception throwing methods, but may
1095 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1096
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1097 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1098 <dd>This attribute indicates that the function should emit a stack smashing
1099 protector. It is in the form of a "canary"&mdash;a random value placed on
1100 the stack before the local variables that's checked upon return from the
1101 function to see if it has been overwritten. A heuristic is used to
1102 determine if a function needs stack protectors or not.<br>
1103<br>
1104 If a function that has an <tt>ssp</tt> attribute is inlined into a
1105 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1106 function will have an <tt>ssp</tt> attribute.</dd>
1107
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1108 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1109 <dd>This attribute indicates that the function should <em>always</em> emit a
1110 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1111 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1112<br>
1113 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1114 function that doesn't have an <tt>sspreq</tt> attribute or which has
1115 an <tt>ssp</tt> attribute, then the resulting function will have
1116 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1117
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1118 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1119 <dd>This attribute indicates that the code generator should not use a red
1120 zone, even if the target-specific ABI normally permits it.</dd>
1121
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1122 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1123 <dd>This attributes disables implicit floating point instructions.</dd>
1124
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1125 <dt><tt><b>naked</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1126 <dd>This attribute disables prologue / epilogue emission for the function.
1127 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1128</dl>
1129
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1130</div>
1131
1132<!-- ======================================================================= -->
1133<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1134 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1135</div>
1136
1137<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1138
1139<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1140 the GCC "file scope inline asm" blocks. These blocks are internally
1141 concatenated by LLVM and treated as a single unit, but may be separated in
1142 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1143
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1144<div class="doc_code">
1145<pre>
1146module asm "inline asm code goes here"
1147module asm "more can go here"
1148</pre>
1149</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1150
1151<p>The strings can contain any character by escaping non-printable characters.
1152 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]1153 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1154
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1155<p>The inline asm code is simply printed to the machine code .s file when
1156 assembly code is generated.</p>
1157
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1158</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1159
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1160<!-- ======================================================================= -->
1161<div class="doc_subsection">
1162 <a name="datalayout">Data Layout</a>
1163</div>
1164
1165<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1166
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1167<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1168 data is to be laid out in memory. The syntax for the data layout is
1169 simply:</p>
1170
1171<div class="doc_code">
1172<pre>
1173target datalayout = "<i>layout specification</i>"
1174</pre>
1175</div>
1176
1177<p>The <i>layout specification</i> consists of a list of specifications
1178 separated by the minus sign character ('-'). Each specification starts with
1179 a letter and may include other information after the letter to define some
1180 aspect of the data layout. The specifications accepted are as follows:</p>
1181
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1182<dl>
1183 <dt><tt>E</tt></dt>
1184 <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]1185 bits with the most significance have the lowest address location.</dd>
1186
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1187 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1188 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1189 the bits with the least significance have the lowest address
1190 location.</dd>
1191
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1192 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1193 <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]1194 <i>preferred</i> alignments. All sizes are in bits. Specifying
1195 the <i>pref</i> alignment is optional. If omitted, the
1196 preceding <tt>:</tt> should be omitted too.</dd>
1197
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1198 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1199 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1200 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1201
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1202 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1203 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1204 <i>size</i>.</dd>
1205
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1206 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1207 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1208 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1209 (double).</dd>
1210
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1211 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1212 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1213 <i>size</i>.</dd>
1214
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1215 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1216 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1217 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1218
1219 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1220 <dd>This specifies a set of native integer widths for the target CPU
1221 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1222 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
1223 this set are considered to support most general arithmetic
1224 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1225</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1226
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1227<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1228 default set of specifications which are then (possibly) overriden by the
1229 specifications in the <tt>datalayout</tt> keyword. The default specifications
1230 are given in this list:</p>
1231
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1232<ul>
1233 <li><tt>E</tt> - big endian</li>
1234 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1235 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1236 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1237 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1238 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1239 <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]1240 alignment of 64-bits</li>
1241 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1242 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1243 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1244 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1245 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1246 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1247</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1248
1249<p>When LLVM is determining the alignment for a given type, it uses the
1250 following rules:</p>
1251
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1252<ol>
1253 <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]1254 specification is used.</li>
1255
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1256 <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]1257 smallest integer type that is larger than the bitwidth of the sought type
1258 is used. If none of the specifications are larger than the bitwidth then
1259 the the largest integer type is used. For example, given the default
1260 specifications above, the i7 type will use the alignment of i8 (next
1261 largest) while both i65 and i256 will use the alignment of i64 (largest
1262 specified).</li>
1263
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1264 <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]1265 largest vector type that is smaller than the sought vector type will be
1266 used as a fall back. This happens because &lt;128 x double&gt; can be
1267 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1268</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1269
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1270</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1271
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1272<!-- ======================================================================= -->
1273<div class="doc_subsection">
1274 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1275</div>
1276
1277<div class="doc_text">
1278
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1279<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1280with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1281is undefined. Pointer values are associated with address ranges
1282according to the following rules:</p>
1283
1284<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1285 <li>A pointer value formed from a
1286 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1287 is associated with the addresses associated with the first operand
1288 of the <tt>getelementptr</tt>.</li>
1289 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1290 range of the variable's storage.</li>
1291 <li>The result value of an allocation instruction is associated with
1292 the address range of the allocated storage.</li>
1293 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1294 no address.</li>
1295 <li>A pointer value formed by an
1296 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1297 address ranges of all pointer values that contribute (directly or
1298 indirectly) to the computation of the pointer's value.</li>
1299 <li>The result value of a
1300 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1301 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1302 <li>An integer constant other than zero or a pointer value returned
1303 from a function not defined within LLVM may be associated with address
1304 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1305 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1306 allocated by mechanisms provided by LLVM.</li>
1307 </ul>
1308
1309<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1310<tt><a href="#i_load">load</a></tt> merely indicates the size and
1311alignment of the memory from which to load, as well as the
1312interpretation of the value. The first operand of a
1313<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1314and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1315
1316<p>Consequently, type-based alias analysis, aka TBAA, aka
1317<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1318LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1319additional information which specialized optimization passes may use
1320to implement type-based alias analysis.</p>
1321
1322</div>
1323
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1324<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1325<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1326<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1327
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1328<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1329
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1330<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1331 intermediate representation. Being typed enables a number of optimizations
1332 to be performed on the intermediate representation directly, without having
1333 to do extra analyses on the side before the transformation. A strong type
1334 system makes it easier to read the generated code and enables novel analyses
1335 and transformations that are not feasible to perform on normal three address
1336 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1337
1338</div>
1339
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1340<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1341<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1342Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1343
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1344<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1345
1346<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1347
1348<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1349 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1350 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1351 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1352 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1353 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1354 </tr>
1355 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1356 <td><a href="#t_floating">floating point</a></td>
1357 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1358 </tr>
1359 <tr>
1360 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1361 <td><a href="#t_integer">integer</a>,
1362 <a href="#t_floating">floating point</a>,
1363 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1364 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1365 <a href="#t_struct">structure</a>,
1366 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1367 <a href="#t_label">label</a>,
1368 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1369 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1370 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1371 <tr>
1372 <td><a href="#t_primitive">primitive</a></td>
1373 <td><a href="#t_label">label</a>,
1374 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1375 <a href="#t_floating">floating point</a>,
1376 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1377 </tr>
1378 <tr>
1379 <td><a href="#t_derived">derived</a></td>
1380 <td><a href="#t_integer">integer</a>,
1381 <a href="#t_array">array</a>,
1382 <a href="#t_function">function</a>,
1383 <a href="#t_pointer">pointer</a>,
1384 <a href="#t_struct">structure</a>,
1385 <a href="#t_pstruct">packed structure</a>,
1386 <a href="#t_vector">vector</a>,
1387 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1388 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1389 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1390 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1391</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1392
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1393<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1394 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1395 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1396
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1397</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1398
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1399<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1400<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1401
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1402<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1403
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1404<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1405 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1406
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1407</div>
1408
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1409<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1410<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1411
1412<div class="doc_text">
1413
1414<h5>Overview:</h5>
1415<p>The integer type is a very simple type that simply specifies an arbitrary
1416 bit width for the integer type desired. Any bit width from 1 bit to
1417 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1418
1419<h5>Syntax:</h5>
1420<pre>
1421 iN
1422</pre>
1423
1424<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1425 value.</p>
1426
1427<h5>Examples:</h5>
1428<table class="layout">
1429 <tr class="layout">
1430 <td class="left"><tt>i1</tt></td>
1431 <td class="left">a single-bit integer.</td>
1432 </tr>
1433 <tr class="layout">
1434 <td class="left"><tt>i32</tt></td>
1435 <td class="left">a 32-bit integer.</td>
1436 </tr>
1437 <tr class="layout">
1438 <td class="left"><tt>i1942652</tt></td>
1439 <td class="left">a really big integer of over 1 million bits.</td>
1440 </tr>
1441</table>
1442
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1443</div>
1444
1445<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1446<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1447
1448<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1449
1450<table>
1451 <tbody>
1452 <tr><th>Type</th><th>Description</th></tr>
1453 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1454 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1455 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1456 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1457 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1458 </tbody>
1459</table>
1460
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1461</div>
1462
1463<!-- _______________________________________________________________________ -->
1464<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1465
1466<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1467
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1468<h5>Overview:</h5>
1469<p>The void type does not represent any value and has no size.</p>
1470
1471<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1472<pre>
1473 void
1474</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1475
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1476</div>
1477
1478<!-- _______________________________________________________________________ -->
1479<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1480
1481<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1482
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1483<h5>Overview:</h5>
1484<p>The label type represents code labels.</p>
1485
1486<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1487<pre>
1488 label
1489</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1490
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1491</div>
1492
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1493<!-- _______________________________________________________________________ -->
1494<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1495
1496<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1497
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1498<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1499<p>The metadata type represents embedded metadata. No derived types may be
1500 created from metadata except for <a href="#t_function">function</a>
1501 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1502
1503<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1504<pre>
1505 metadata
1506</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1507
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1508</div>
1509
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1510
1511<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1512<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1513
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1514<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1516<p>The real power in LLVM comes from the derived types in the system. This is
1517 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1518 useful types. Each of these types contain one or more element types which
1519 may be a primitive type, or another derived type. For example, it is
1520 possible to have a two dimensional array, using an array as the element type
1521 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1522
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1523</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1524
1525<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1526<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1527
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1528<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1529
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1530<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1531<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1532 sequentially in memory. The array type requires a size (number of elements)
1533 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1534
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1535<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1536<pre>
1537 [&lt;# elements&gt; x &lt;elementtype&gt;]
1538</pre>
1539
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1540<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1541 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1542
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1543<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1544<table class="layout">
1545 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1546 <td class="left"><tt>[40 x i32]</tt></td>
1547 <td class="left">Array of 40 32-bit integer values.</td>
1548 </tr>
1549 <tr class="layout">
1550 <td class="left"><tt>[41 x i32]</tt></td>
1551 <td class="left">Array of 41 32-bit integer values.</td>
1552 </tr>
1553 <tr class="layout">
1554 <td class="left"><tt>[4 x i8]</tt></td>
1555 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1556 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1557</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1558<p>Here are some examples of multidimensional arrays:</p>
1559<table class="layout">
1560 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1561 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1562 <td class="left">3x4 array of 32-bit integer values.</td>
1563 </tr>
1564 <tr class="layout">
1565 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1566 <td class="left">12x10 array of single precision floating point values.</td>
1567 </tr>
1568 <tr class="layout">
1569 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1570 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1571 </tr>
1572</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1573
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1574<p>There is no restriction on indexing beyond the end of the array implied by
1575 a static type (though there are restrictions on indexing beyond the bounds
1576 of an allocated object in some cases). This means that single-dimension
1577 'variable sized array' addressing can be implemented in LLVM with a zero
1578 length array type. An implementation of 'pascal style arrays' in LLVM could
1579 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1580
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1581</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1582
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1583<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1584<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1585
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1586<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1587
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1588<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1589<p>The function type can be thought of as a function signature. It consists of
1590 a return type and a list of formal parameter types. The return type of a
1591 function type is a scalar type, a void type, or a struct type. If the return
1592 type is a struct type then all struct elements must be of first class types,
1593 and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1594
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1595<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1596<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1597 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1598</pre>
1599
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1600<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]1601 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1602 which indicates that the function takes a variable number of arguments.
1603 Variable argument functions can access their arguments with
1604 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1605 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1606 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1607
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1608<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1609<table class="layout">
1610 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1611 <td class="left"><tt>i32 (i32)</tt></td>
1612 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1613 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1614 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1615 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1616 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1617 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1618 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1619 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1620 <tt>float</tt>.
1621 </td>
1622 </tr><tr class="layout">
1623 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1624 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1625 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1626 which returns an integer. This is the signature for <tt>printf</tt> in
1627 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1628 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1629 </tr><tr class="layout">
1630 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1631 <td class="left">A function taking an <tt>i32</tt>, returning a
1632 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1633 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1634 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1635</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1636
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1637</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1638
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1639<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1640<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1641
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1642<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1643
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1644<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1645<p>The structure type is used to represent a collection of data members together
1646 in memory. The packing of the field types is defined to match the ABI of the
1647 underlying processor. The elements of a structure may be any type that has a
1648 size.</p>
1649
1650<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1651 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1652 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1653
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1654<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1655<pre>
1656 { &lt;type list&gt; }
1657</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1658
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1659<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1660<table class="layout">
1661 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1662 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1663 <td class="left">A triple of three <tt>i32</tt> values</td>
1664 </tr><tr class="layout">
1665 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1666 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1667 second element is a <a href="#t_pointer">pointer</a> to a
1668 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1669 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1670 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1671</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1672
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1673</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1674
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1675<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1676<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1677</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1678
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1679<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1680
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1681<h5>Overview:</h5>
1682<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1683 together in memory. There is no padding between fields. Further, the
1684 alignment of a packed structure is 1 byte. The elements of a packed
1685 structure may be any type that has a size.</p>
1686
1687<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1688 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1689 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1690
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1691<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1692<pre>
1693 &lt; { &lt;type list&gt; } &gt;
1694</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1695
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1696<h5>Examples:</h5>
1697<table class="layout">
1698 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1699 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1700 <td class="left">A triple of three <tt>i32</tt> values</td>
1701 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1702 <td class="left">
1703<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1704 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1705 second element is a <a href="#t_pointer">pointer</a> to a
1706 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1707 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1708 </tr>
1709</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1710
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1711</div>
1712
1713<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1714<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1715
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1716<div class="doc_text">
1717
1718<h5>Overview:</h5>
1719<p>As in many languages, the pointer type represents a pointer or reference to
1720 another object, which must live in memory. Pointer types may have an optional
1721 address space attribute defining the target-specific numbered address space
1722 where the pointed-to object resides. The default address space is zero.</p>
1723
1724<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1725 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1726
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1727<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1728<pre>
1729 &lt;type&gt; *
1730</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1731
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1732<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1733<table class="layout">
1734 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1735 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1736 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1737 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1738 </tr>
1739 <tr class="layout">
1740 <td class="left"><tt>i32 (i32 *) *</tt></td>
1741 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1742 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1743 <tt>i32</tt>.</td>
1744 </tr>
1745 <tr class="layout">
1746 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1747 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1748 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1749 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1750</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1751
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1752</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1753
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1754<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1755<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1756
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1757<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1758
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1759<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1760<p>A vector type is a simple derived type that represents a vector of elements.
1761 Vector types are used when multiple primitive data are operated in parallel
1762 using a single instruction (SIMD). A vector type requires a size (number of
1763 elements) and an underlying primitive data type. Vectors must have a power
1764 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1765 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1766
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1767<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1768<pre>
1769 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1770</pre>
1771
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1772<p>The number of elements is a constant integer value; elementtype may be any
1773 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1774
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1775<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1776<table class="layout">
1777 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1778 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1779 <td class="left">Vector of 4 32-bit integer values.</td>
1780 </tr>
1781 <tr class="layout">
1782 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1783 <td class="left">Vector of 8 32-bit floating-point values.</td>
1784 </tr>
1785 <tr class="layout">
1786 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1787 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1788 </tr>
1789</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1790
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1791</div>
1792
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1793<!-- _______________________________________________________________________ -->
1794<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1795<div class="doc_text">
1796
1797<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1798<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1799 corresponds (for example) to the C notion of a forward declared structure
1800 type. In LLVM, opaque types can eventually be resolved to any type (not just
1801 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1802
1803<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1804<pre>
1805 opaque
1806</pre>
1807
1808<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1809<table class="layout">
1810 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1811 <td class="left"><tt>opaque</tt></td>
1812 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1813 </tr>
1814</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1815
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1816</div>
1817
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1818<!-- ======================================================================= -->
1819<div class="doc_subsection">
1820 <a name="t_uprefs">Type Up-references</a>
1821</div>
1822
1823<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1824
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1825<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1826<p>An "up reference" allows you to refer to a lexically enclosing type without
1827 requiring it to have a name. For instance, a structure declaration may
1828 contain a pointer to any of the types it is lexically a member of. Example
1829 of up references (with their equivalent as named type declarations)
1830 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1831
1832<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1833 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1834 { \2 }* %y = type { %y }*
1835 \1* %z = type %z*
1836</pre>
1837
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1838<p>An up reference is needed by the asmprinter for printing out cyclic types
1839 when there is no declared name for a type in the cycle. Because the
1840 asmprinter does not want to print out an infinite type string, it needs a
1841 syntax to handle recursive types that have no names (all names are optional
1842 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1843
1844<h5>Syntax:</h5>
1845<pre>
1846 \&lt;level&gt;
1847</pre>
1848
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1849<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]1850
1851<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1852<table class="layout">
1853 <tr class="layout">
1854 <td class="left"><tt>\1*</tt></td>
1855 <td class="left">Self-referential pointer.</td>
1856 </tr>
1857 <tr class="layout">
1858 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1859 <td class="left">Recursive structure where the upref refers to the out-most
1860 structure.</td>
1861 </tr>
1862</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1863
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1864</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1865
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1866<!-- *********************************************************************** -->
1867<div class="doc_section"> <a name="constants">Constants</a> </div>
1868<!-- *********************************************************************** -->
1869
1870<div class="doc_text">
1871
1872<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1873 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1874
1875</div>
1876
1877<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1878<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1879
1880<div class="doc_text">
1881
1882<dl>
1883 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1884 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1885 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1886
1887 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1888 <dd>Standard integers (such as '4') are constants of
1889 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1890 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1891
1892 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1893 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1894 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1895 notation (see below). The assembler requires the exact decimal value of a
1896 floating-point constant. For example, the assembler accepts 1.25 but
1897 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1898 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1899
1900 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1901 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1902 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1903</dl>
1904
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1905<p>The one non-intuitive notation for constants is the hexadecimal form of
1906 floating point constants. For example, the form '<tt>double
1907 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1908 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1909 constants are required (and the only time that they are generated by the
1910 disassembler) is when a floating point constant must be emitted but it cannot
1911 be represented as a decimal floating point number in a reasonable number of
1912 digits. For example, NaN's, infinities, and other special values are
1913 represented in their IEEE hexadecimal format so that assembly and disassembly
1914 do not cause any bits to change in the constants.</p>
1915
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]1916<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1917 represented using the 16-digit form shown above (which matches the IEEE754
1918 representation for double); float values must, however, be exactly
1919 representable as IEE754 single precision. Hexadecimal format is always used
1920 for long double, and there are three forms of long double. The 80-bit format
1921 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1922 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1923 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1924 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1925 currently supported target uses this format. Long doubles will only work if
1926 they match the long double format on your target. All hexadecimal formats
1927 are big-endian (sign bit at the left).</p>
1928
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1929</div>
1930
1931<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1932<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]1933<a name="aggregateconstants"></a> <!-- old anchor -->
1934<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1935</div>
1936
1937<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1938
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1939<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1940 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1941
1942<dl>
1943 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1944 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1945 type definitions (a comma separated list of elements, surrounded by braces
1946 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1947 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1948 Structure constants must have <a href="#t_struct">structure type</a>, and
1949 the number and types of elements must match those specified by the
1950 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1951
1952 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1953 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1954 definitions (a comma separated list of elements, surrounded by square
1955 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1956 ]</tt>". Array constants must have <a href="#t_array">array 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
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1960 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1961 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1962 definitions (a comma separated list of elements, surrounded by
1963 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1964 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1965 have <a href="#t_vector">vector type</a>, and the number and types of
1966 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1967
1968 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1969 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1970 value to zero of <em>any</em> type, including scalar and aggregate types.
1971 This is often used to avoid having to print large zero initializers
1972 (e.g. for large arrays) and is always exactly equivalent to using explicit
1973 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]1974
1975 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]1976 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1977 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1978 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1979 be interpreted as part of the instruction stream, metadata is a place to
1980 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1981</dl>
1982
1983</div>
1984
1985<!-- ======================================================================= -->
1986<div class="doc_subsection">
1987 <a name="globalconstants">Global Variable and Function Addresses</a>
1988</div>
1989
1990<div class="doc_text">
1991
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1992<p>The addresses of <a href="#globalvars">global variables</a>
1993 and <a href="#functionstructure">functions</a> are always implicitly valid
1994 (link-time) constants. These constants are explicitly referenced when
1995 the <a href="#identifiers">identifier for the global</a> is used and always
1996 have <a href="#t_pointer">pointer</a> type. For example, the following is a
1997 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1998
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1999<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2000<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2001@X = global i32 17
2002@Y = global i32 42
2003@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2004</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2005</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2006
2007</div>
2008
2009<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2010<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2011<div class="doc_text">
2012
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2013<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]2014 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2015 Undefined values may be of any type (other than label or void) and be used
2016 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2017
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2018<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2019 program is well defined no matter what value is used. This gives the
2020 compiler more freedom to optimize. Here are some examples of (potentially
2021 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2022
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2023
2024<div class="doc_code">
2025<pre>
2026 %A = add %X, undef
2027 %B = sub %X, undef
2028 %C = xor %X, undef
2029Safe:
2030 %A = undef
2031 %B = undef
2032 %C = undef
2033</pre>
2034</div>
2035
2036<p>This is safe because all of the output bits are affected by the undef bits.
2037Any output bit can have a zero or one depending on the input bits.</p>
2038
2039<div class="doc_code">
2040<pre>
2041 %A = or %X, undef
2042 %B = and %X, undef
2043Safe:
2044 %A = -1
2045 %B = 0
2046Unsafe:
2047 %A = undef
2048 %B = undef
2049</pre>
2050</div>
2051
2052<p>These logical operations have bits that are not always affected by the input.
2053For example, if "%X" has a zero bit, then the output of the 'and' operation will
2054always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2055such, it is unsafe to optimize or assume that the result of the and is undef.
2056However, it is safe to assume that all bits of the undef could be 0, and
2057optimize the and to 0. Likewise, it is safe to assume that all the bits of
2058the undef operand to the or could be set, allowing the or to be folded to
2059-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2060
2061<div class="doc_code">
2062<pre>
2063 %A = select undef, %X, %Y
2064 %B = select undef, 42, %Y
2065 %C = select %X, %Y, undef
2066Safe:
2067 %A = %X (or %Y)
2068 %B = 42 (or %Y)
2069 %C = %Y
2070Unsafe:
2071 %A = undef
2072 %B = undef
2073 %C = undef
2074</pre>
2075</div>
2076
2077<p>This set of examples show that undefined select (and conditional branch)
2078conditions can go "either way" but they have to come from one of the two
2079operands. In the %A example, if %X and %Y were both known to have a clear low
2080bit, then %A would have to have a cleared low bit. However, in the %C example,
2081the optimizer is allowed to assume that the undef operand could be the same as
2082%Y, allowing the whole select to be eliminated.</p>
2083
2084
2085<div class="doc_code">
2086<pre>
2087 %A = xor undef, undef
2088
2089 %B = undef
2090 %C = xor %B, %B
2091
2092 %D = undef
2093 %E = icmp lt %D, 4
2094 %F = icmp gte %D, 4
2095
2096Safe:
2097 %A = undef
2098 %B = undef
2099 %C = undef
2100 %D = undef
2101 %E = undef
2102 %F = undef
2103</pre>
2104</div>
2105
2106<p>This example points out that two undef operands are not necessarily the same.
2107This can be surprising to people (and also matches C semantics) where they
2108assume that "X^X" is always zero, even if X is undef. This isn't true for a
2109number of reasons, but the short answer is that an undef "variable" can
2110arbitrarily change its value over its "live range". This is true because the
2111"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2112logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2113so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2114to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2115would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2116
2117<div class="doc_code">
2118<pre>
2119 %A = fdiv undef, %X
2120 %B = fdiv %X, undef
2121Safe:
2122 %A = undef
2123b: unreachable
2124</pre>
2125</div>
2126
2127<p>These examples show the crucial difference between an <em>undefined
2128value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2129allowed to have an arbitrary bit-pattern. This means that the %A operation
2130can be constant folded to undef because the undef could be an SNaN, and fdiv is
2131not (currently) defined on SNaN's. However, in the second example, we can make
2132a more aggressive assumption: because the undef is allowed to be an arbitrary
2133value, 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]2134has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2135does not execute at all. This allows us to delete the divide and all code after
2136it: since the undefined operation "can't happen", the optimizer can assume that
2137it occurs in dead code.
2138</p>
2139
2140<div class="doc_code">
2141<pre>
2142a: store undef -> %X
2143b: store %X -> undef
2144Safe:
2145a: &lt;deleted&gt;
2146b: unreachable
2147</pre>
2148</div>
2149
2150<p>These examples reiterate the fdiv example: a store "of" an undefined value
2151can be assumed to not have any effect: we can assume that the value is
2152overwritten with bits that happen to match what was already there. However, a
2153store "to" an undefined location could clobber arbitrary memory, therefore, it
2154has undefined behavior.</p>
2155
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2156</div>
2157
2158<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2159<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2160 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2161<div class="doc_text">
2162
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2163<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2164
2165<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2166 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2167 the address of the entry block is illegal.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2168
2169<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2170 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2171 against null. Pointer equality tests between labels addresses is undefined
2172 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2173 equal to the null pointer. This may also be passed around as an opaque
2174 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2175 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2176 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2177
2178<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2179 using the value as the operand to an inline assembly, but that is target
2180 specific.
2181 </p>
2182
2183</div>
2184
2185
2186<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2187<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2188</div>
2189
2190<div class="doc_text">
2191
2192<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2193 to be used as constants. Constant expressions may be of
2194 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2195 operation that does not have side effects (e.g. load and call are not
2196 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2197
2198<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2199 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2200 <dd>Truncate a constant to another type. The bit size of CST must be larger
2201 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2202
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2203 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2204 <dd>Zero extend a constant to another type. The bit size of CST must be
2205 smaller or equal to the bit size of TYPE. Both types must be
2206 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2207
2208 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2209 <dd>Sign extend a constant to another type. The bit size of CST must be
2210 smaller or equal to the bit size of TYPE. Both types must be
2211 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2212
2213 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2214 <dd>Truncate a floating point constant to another floating point type. The
2215 size of CST must be larger than the size of TYPE. Both types must be
2216 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2217
2218 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2219 <dd>Floating point extend a constant to another type. The size of CST must be
2220 smaller or equal to the size of TYPE. Both types must be floating
2221 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2222
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2223 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2224 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2225 constant. TYPE must be a scalar or vector integer type. CST must be of
2226 scalar or vector floating point type. Both CST and TYPE must be scalars,
2227 or vectors of the same number of elements. If the value won't fit in the
2228 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2229
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2230 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2231 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2232 constant. TYPE must be a scalar or vector integer type. CST must be of
2233 scalar or vector floating point type. Both CST and TYPE must be scalars,
2234 or vectors of the same number of elements. If the value won't fit in the
2235 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2236
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2237 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2238 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2239 constant. TYPE must be a scalar or vector floating point type. CST must be
2240 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2241 vectors of the same number of elements. If the value won't fit in the
2242 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2243
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2244 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2245 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2246 constant. TYPE must be a scalar or vector floating point type. CST must be
2247 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2248 vectors of the same number of elements. If the value won't fit in the
2249 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2250
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2251 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2252 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2253 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2254 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2255 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2256
2257 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2258 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2259 type. CST must be of integer type. The CST value is zero extended,
2260 truncated, or unchanged to make it fit in a pointer size. This one is
2261 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2262
2263 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2264 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2265 are the same as those for the <a href="#i_bitcast">bitcast
2266 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2267
2268 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2269 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2270 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2271 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2272 instruction, the index list may have zero or more indexes, which are
2273 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2274
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2275 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2276 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2277
2278 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2279 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2280
2281 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2282 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2283
2284 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2285 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2286 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2287
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2288 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2289 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2290 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2291
2292 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2293 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2294 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2295
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2296 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2297 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2298 be any of the <a href="#binaryops">binary</a>
2299 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2300 on operands are the same as those for the corresponding instruction
2301 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2302</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2303
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2304</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2305
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2306<!-- ======================================================================= -->
2307<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2308</div>
2309
2310<div class="doc_text">
2311
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2312<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2313 stream without affecting the behaviour of the program. There are two
2314 metadata primitives, strings and nodes. All metadata has the
2315 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2316 point ('<tt>!</tt>').</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2317
2318<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2319 any character by escaping non-printable characters with "\xx" where "xx" is
2320 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2321
2322<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2323 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2324 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2325 10}</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2326
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2327<p>A metadata node will attempt to track changes to the values it holds. In the
2328 event that a value is deleted, it will be replaced with a typeless
2329 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckycb337992009-05-10 20:57:05 +0000[diff] [blame]2330
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2331<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2332 the program that isn't available in the instructions, or that isn't easily
2333 computable. Similarly, the code generator may expect a certain metadata
2334 format to be used to express debugging information.</p>
2335
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2336</div>
2337
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2338<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2339<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2340<!-- *********************************************************************** -->
2341
2342<!-- ======================================================================= -->
2343<div class="doc_subsection">
2344<a name="inlineasm">Inline Assembler Expressions</a>
2345</div>
2346
2347<div class="doc_text">
2348
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2349<p>LLVM supports inline assembler expressions (as opposed
2350 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2351 a special value. This value represents the inline assembler as a string
2352 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2353 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2354 expression has side effects, and a flag indicating whether the function
2355 containing the asm needs to align its stack conservatively. An example
2356 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2357
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2358<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2359<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2360i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2361</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2362</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2363
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2364<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2365 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2366 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2367
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2368<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2369<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2370%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]2371</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2372</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2373
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2374<p>Inline asms with side effects not visible in the constraint list must be
2375 marked as having side effects. This is done through the use of the
2376 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2377
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2378<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2379<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2380call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2381</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2382</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2383
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2384<p>In some cases inline asms will contain code that will not work unless the
2385 stack is aligned in some way, such as calls or SSE instructions on x86,
2386 yet will not contain code that does that alignment within the asm.
2387 The compiler should make conservative assumptions about what the asm might
2388 contain and should generate its usual stack alignment code in the prologue
2389 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2390
2391<div class="doc_code">
2392<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2393call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2394</pre>
2395</div>
2396
2397<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2398 first.</p>
2399
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2400<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2401 documented here. Constraints on what can be done (e.g. duplication, moving,
2402 etc need to be documented). This is probably best done by reference to
2403 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2404
2405</div>
2406
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2407
2408<!-- *********************************************************************** -->
2409<div class="doc_section">
2410 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2411</div>
2412<!-- *********************************************************************** -->
2413
2414<p>LLVM has a number of "magic" global variables that contain data that affect
2415code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2416of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2417section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2418by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2419
2420<!-- ======================================================================= -->
2421<div class="doc_subsection">
2422<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2423</div>
2424
2425<div class="doc_text">
2426
2427<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2428href="#linkage_appending">appending linkage</a>. This array contains a list of
2429pointers to global variables and functions which may optionally have a pointer
2430cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2431
2432<pre>
2433 @X = global i8 4
2434 @Y = global i32 123
2435
2436 @llvm.used = appending global [2 x i8*] [
2437 i8* @X,
2438 i8* bitcast (i32* @Y to i8*)
2439 ], section "llvm.metadata"
2440</pre>
2441
2442<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2443compiler, assembler, and linker are required to treat the symbol as if there is
2444a reference to the global that it cannot see. For example, if a variable has
2445internal linkage and no references other than that from the <tt>@llvm.used</tt>
2446list, it cannot be deleted. This is commonly used to represent references from
2447inline asms and other things the compiler cannot "see", and corresponds to
2448"attribute((used))" in GNU C.</p>
2449
2450<p>On some targets, the code generator must emit a directive to the assembler or
2451object file to prevent the assembler and linker from molesting the symbol.</p>
2452
2453</div>
2454
2455<!-- ======================================================================= -->
2456<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2457<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2458</div>
2459
2460<div class="doc_text">
2461
2462<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2463<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2464touching the symbol. On targets that support it, this allows an intelligent
2465linker to optimize references to the symbol without being impeded as it would be
2466by <tt>@llvm.used</tt>.</p>
2467
2468<p>This is a rare construct that should only be used in rare circumstances, and
2469should not be exposed to source languages.</p>
2470
2471</div>
2472
2473<!-- ======================================================================= -->
2474<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2475<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2476</div>
2477
2478<div class="doc_text">
2479
2480<p>TODO: Describe this.</p>
2481
2482</div>
2483
2484<!-- ======================================================================= -->
2485<div class="doc_subsection">
2486<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2487</div>
2488
2489<div class="doc_text">
2490
2491<p>TODO: Describe this.</p>
2492
2493</div>
2494
2495
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2496<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2497<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2498<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2499
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2500<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2501
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2502<p>The LLVM instruction set consists of several different classifications of
2503 instructions: <a href="#terminators">terminator
2504 instructions</a>, <a href="#binaryops">binary instructions</a>,
2505 <a href="#bitwiseops">bitwise binary instructions</a>,
2506 <a href="#memoryops">memory instructions</a>, and
2507 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2508
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2509</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2510
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2511<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2512<div class="doc_subsection"> <a name="terminators">Terminator
2513Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2514
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2515<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2516
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2517<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2518 in a program ends with a "Terminator" instruction, which indicates which
2519 block should be executed after the current block is finished. These
2520 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2521 control flow, not values (the one exception being the
2522 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2523
2524<p>There are six different terminator instructions: the
2525 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2526 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2527 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2528 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2529 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2530 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2531 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2532
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2533</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2534
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2535<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2536<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2537Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2538
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2539<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2540
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2541<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2542<pre>
2543 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]2544 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2545</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2546
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2547<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2548<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2549 a value) from a function back to the caller.</p>
2550
2551<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2552 value and then causes control flow, and one that just causes control flow to
2553 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2554
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2555<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2556<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2557 return value. The type of the return value must be a
2558 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2559
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2560<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2561 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2562 value or a return value with a type that does not match its type, or if it
2563 has a void return type and contains a '<tt>ret</tt>' instruction with a
2564 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2565
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2566<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2567<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2568 the calling function's context. If the caller is a
2569 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2570 instruction after the call. If the caller was an
2571 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2572 the beginning of the "normal" destination block. If the instruction returns
2573 a value, that value shall set the call or invoke instruction's return
2574 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2575
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2576<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2577<pre>
2578 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2579 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2580 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]2581</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2582
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2583</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2584<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2585<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2586
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2587<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2589<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2590<pre>
2591 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]2592</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2594<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2595<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2596 different basic block in the current function. There are two forms of this
2597 instruction, corresponding to a conditional branch and an unconditional
2598 branch.</p>
2599
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2600<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2601<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2602 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2603 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2604 target.</p>
2605
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2606<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2607<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2608 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2609 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2610 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2611
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2612<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2613<pre>
2614Test:
2615 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2616 br i1 %cond, label %IfEqual, label %IfUnequal
2617IfEqual:
2618 <a href="#i_ret">ret</a> i32 1
2619IfUnequal:
2620 <a href="#i_ret">ret</a> i32 0
2621</pre>
2622
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2623</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2624
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2625<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2626<div class="doc_subsubsection">
2627 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2628</div>
2629
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2630<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2631
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2632<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2633<pre>
2634 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2635</pre>
2636
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2637<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2638<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]2639 several different places. It is a generalization of the '<tt>br</tt>'
2640 instruction, allowing a branch to occur to one of many possible
2641 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2642
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2643<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2644<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2645 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2646 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2647 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2648
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2649<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2650<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2651 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2652 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2653 transferred to the corresponding destination; otherwise, control flow is
2654 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2655
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2656<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2657<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2658 <tt>switch</tt> instruction, this instruction may be code generated in
2659 different ways. For example, it could be generated as a series of chained
2660 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2661
2662<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2663<pre>
2664 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2665 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2666 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2667
2668 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2669 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2670
2671 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2672 switch i32 %val, label %otherwise [ i32 0, label %onzero
2673 i32 1, label %onone
2674 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2675</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2676
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2677</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2678
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2679
2680<!-- _______________________________________________________________________ -->
2681<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2682 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2683</div>
2684
2685<div class="doc_text">
2686
2687<h5>Syntax:</h5>
2688<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2689 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]2690</pre>
2691
2692<h5>Overview:</h5>
2693
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2694<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2695 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2696 "<tt>address</tt>". Address must be derived from a <a
2697 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2698
2699<h5>Arguments:</h5>
2700
2701<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2702 rest of the arguments indicate the full set of possible destinations that the
2703 address may point to. Blocks are allowed to occur multiple times in the
2704 destination list, though this isn't particularly useful.</p>
2705
2706<p>This destination list is required so that dataflow analysis has an accurate
2707 understanding of the CFG.</p>
2708
2709<h5>Semantics:</h5>
2710
2711<p>Control transfers to the block specified in the address argument. All
2712 possible destination blocks must be listed in the label list, otherwise this
2713 instruction has undefined behavior. This implies that jumps to labels
2714 defined in other functions have undefined behavior as well.</p>
2715
2716<h5>Implementation:</h5>
2717
2718<p>This is typically implemented with a jump through a register.</p>
2719
2720<h5>Example:</h5>
2721<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2722 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2723</pre>
2724
2725</div>
2726
2727
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2728<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2729<div class="doc_subsubsection">
2730 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2731</div>
2732
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2733<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2734
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2735<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2736<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2737 &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]2738 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2739</pre>
2740
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2741<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2742<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2743 function, with the possibility of control flow transfer to either the
2744 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2745 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2746 control flow will return to the "normal" label. If the callee (or any
2747 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2748 instruction, control is interrupted and continued at the dynamically nearest
2749 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2750
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2751<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2752<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2753
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2754<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2755 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2756 convention</a> the call should use. If none is specified, the call
2757 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2758
2759 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2760 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2761 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2762
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2763 <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]2764 function value being invoked. In most cases, this is a direct function
2765 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2766 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2767
2768 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2769 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2770
2771 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2772 signature argument types. If the function signature indicates the
2773 function accepts a variable number of arguments, the extra arguments can
2774 be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2775
2776 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2777 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2778
2779 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2780 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2781
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2782 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2783 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2784 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2785</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2786
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2787<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2788<p>This instruction is designed to operate as a standard
2789 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2790 primary difference is that it establishes an association with a label, which
2791 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2792
2793<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2794 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2795 exception. Additionally, this is important for implementation of
2796 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2797
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2798<p>For the purposes of the SSA form, the definition of the value returned by the
2799 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2800 block to the "normal" label. If the callee unwinds then no return value is
2801 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]2802
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2803<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2804<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2805 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2806 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2807 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2808 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2809</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2810
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2811</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2812
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2813<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2814
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2815<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2816Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2817
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2818<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2819
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2820<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2821<pre>
2822 unwind
2823</pre>
2824
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2825<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2826<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2827 at the first callee in the dynamic call stack which used
2828 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2829 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2830
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2831<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2832<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2833 immediately halt. The dynamic call stack is then searched for the
2834 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2835 Once found, execution continues at the "exceptional" destination block
2836 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2837 instruction in the dynamic call chain, undefined behavior results.</p>
2838
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2839</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2840
2841<!-- _______________________________________________________________________ -->
2842
2843<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2844Instruction</a> </div>
2845
2846<div class="doc_text">
2847
2848<h5>Syntax:</h5>
2849<pre>
2850 unreachable
2851</pre>
2852
2853<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2854<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2855 instruction is used to inform the optimizer that a particular portion of the
2856 code is not reachable. This can be used to indicate that the code after a
2857 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2858
2859<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2860<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2861
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2862</div>
2863
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2864<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2865<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2866
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2867<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2868
2869<p>Binary operators are used to do most of the computation in a program. They
2870 require two operands of the same type, execute an operation on them, and
2871 produce a single value. The operands might represent multiple data, as is
2872 the case with the <a href="#t_vector">vector</a> data type. The result value
2873 has the same type as its operands.</p>
2874
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2875<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2876
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2877</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2878
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2879<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2880<div class="doc_subsubsection">
2881 <a name="i_add">'<tt>add</tt>' Instruction</a>
2882</div>
2883
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2884<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2886<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2887<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2888 &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]2889 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2890 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2891 &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]2892</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2893
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2894<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2895<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2896
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2897<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2898<p>The two arguments to the '<tt>add</tt>' instruction must
2899 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2900 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2901
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2902<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2903<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2904
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2905<p>If the sum has unsigned overflow, the result returned is the mathematical
2906 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]2907
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2908<p>Because LLVM integers use a two's complement representation, this instruction
2909 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2910
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2911<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2912 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2913 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2914 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2915
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2916<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2917<pre>
2918 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2919</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2920
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2921</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2922
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2923<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2924<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2925 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2926</div>
2927
2928<div class="doc_text">
2929
2930<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2931<pre>
2932 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2933</pre>
2934
2935<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2936<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2937
2938<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2939<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2940 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2941 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2942
2943<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2944<p>The value produced is the floating point sum of the two operands.</p>
2945
2946<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2947<pre>
2948 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2949</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2950
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2951</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2952
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2953<!-- _______________________________________________________________________ -->
2954<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2955 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2956</div>
2957
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2958<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2959
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2960<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2961<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2962 &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]2963 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2964 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2965 &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]2966</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2967
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2968<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2969<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2970 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2971
2972<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2973 '<tt>neg</tt>' instruction present in most other intermediate
2974 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2975
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2976<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2977<p>The two arguments to the '<tt>sub</tt>' instruction must
2978 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2979 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2980
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2981<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2982<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2983
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2984<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2985 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2986 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2987
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2988<p>Because LLVM integers use a two's complement representation, this instruction
2989 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2990
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2991<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2992 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2993 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2994 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2995
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2996<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2997<pre>
2998 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2999 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3000</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3001
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3002</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3003
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3004<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3005<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3006 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3007</div>
3008
3009<div class="doc_text">
3010
3011<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3012<pre>
3013 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3014</pre>
3015
3016<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3017<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3018 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3019
3020<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3021 '<tt>fneg</tt>' instruction present in most other intermediate
3022 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3023
3024<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3025<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3026 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3027 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3028
3029<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3030<p>The value produced is the floating point difference of the two operands.</p>
3031
3032<h5>Example:</h5>
3033<pre>
3034 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3035 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3036</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3037
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3038</div>
3039
3040<!-- _______________________________________________________________________ -->
3041<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3042 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3043</div>
3044
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3045<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3046
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3047<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3048<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3049 &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]3050 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3051 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3052 &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]3053</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3054
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3055<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3056<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3057
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3058<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3059<p>The two arguments to the '<tt>mul</tt>' instruction must
3060 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3061 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3062
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3063<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3064<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3065
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3066<p>If the result of the multiplication has unsigned overflow, the result
3067 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3068 width of the result.</p>
3069
3070<p>Because LLVM integers use a two's complement representation, and the result
3071 is the same width as the operands, this instruction returns the correct
3072 result for both signed and unsigned integers. If a full product
3073 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3074 be sign-extended or zero-extended as appropriate to the width of the full
3075 product.</p>
3076
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3077<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3078 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3079 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3080 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3081
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3082<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3083<pre>
3084 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3085</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3086
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3087</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3088
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3089<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3090<div class="doc_subsubsection">
3091 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3092</div>
3093
3094<div class="doc_text">
3095
3096<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3097<pre>
3098 &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]3099</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3100
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3101<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3102<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3103
3104<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3105<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3106 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3107 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3108
3109<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3110<p>The value produced is the floating point product of the two operands.</p>
3111
3112<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3113<pre>
3114 &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]3115</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3116
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3117</div>
3118
3119<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3120<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3121</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3122
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3123<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3124
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3125<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3126<pre>
3127 &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]3128</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3129
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3130<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3131<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3132
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3133<h5>Arguments:</h5>
3134<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3135 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3136 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3137
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3138<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3139<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3140
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3141<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3142 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3143
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3144<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3145
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3146<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3147<pre>
3148 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3149</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3150
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3151</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3153<!-- _______________________________________________________________________ -->
3154<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3155</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3156
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3157<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3158
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3159<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3160<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3161 &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]3162 &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]3163</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3164
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3165<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3166<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3167
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3168<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3169<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3170 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3171 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3172
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3173<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3174<p>The value produced is the signed integer quotient of the two operands rounded
3175 towards zero.</p>
3176
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3177<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3178 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3179
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3180<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3181 undefined behavior; this is a rare case, but can occur, for example, by doing
3182 a 32-bit division of -2147483648 by -1.</p>
3183
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3184<p>If the <tt>exact</tt> keyword is present, the result value of the
3185 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3186 would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3187
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3188<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3189<pre>
3190 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3191</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3192
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3193</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3194
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3195<!-- _______________________________________________________________________ -->
3196<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3197Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3198
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3199<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3200
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3201<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3202<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3203 &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]3204</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3205
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3206<h5>Overview:</h5>
3207<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3208
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3209<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3210<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3211 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3212 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3213
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3214<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3215<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3216
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3217<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3218<pre>
3219 &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]3220</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3221
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3222</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3223
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3224<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3225<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3226</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3227
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3228<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3229
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3230<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3231<pre>
3232 &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]3233</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3234
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3235<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3236<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3237 division of its two arguments.</p>
3238
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3239<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3240<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3241 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3242 values. Both arguments must have identical types.</p>
3243
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3244<h5>Semantics:</h5>
3245<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3246 This instruction always performs an unsigned division to get the
3247 remainder.</p>
3248
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3249<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3250 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3251
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3252<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3253
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3254<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3255<pre>
3256 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3257</pre>
3258
3259</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3260
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3261<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3262<div class="doc_subsubsection">
3263 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3264</div>
3265
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3266<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3267
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3268<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3269<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3270 &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]3271</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3272
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3273<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3274<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3275 division of its two operands. This instruction can also take
3276 <a href="#t_vector">vector</a> versions of the values in which case the
3277 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3278
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3279<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3280<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3281 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3282 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3283
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3284<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3285<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3286 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3287 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3288 a value. For more information about the difference,
3289 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3290 Math Forum</a>. For a table of how this is implemented in various languages,
3291 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3292 Wikipedia: modulo operation</a>.</p>
3293
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3294<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3295 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3296
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3297<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3298 Overflow also leads to undefined behavior; this is a rare case, but can
3299 occur, for example, by taking the remainder of a 32-bit division of
3300 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3301 lets srem be implemented using instructions that return both the result of
3302 the division and the remainder.)</p>
3303
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3304<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3305<pre>
3306 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3307</pre>
3308
3309</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3310
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3311<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3312<div class="doc_subsubsection">
3313 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3314
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3315<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3316
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3317<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3318<pre>
3319 &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]3320</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3321
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3322<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3323<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3324 its two operands.</p>
3325
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3326<h5>Arguments:</h5>
3327<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3328 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3329 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3330
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3331<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3332<p>This instruction returns the <i>remainder</i> of a division. The remainder
3333 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3334
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3335<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3336<pre>
3337 &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]3338</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3340</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3341
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3342<!-- ======================================================================= -->
3343<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3344Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3345
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3346<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3347
3348<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3349 program. They are generally very efficient instructions and can commonly be
3350 strength reduced from other instructions. They require two operands of the
3351 same type, execute an operation on them, and produce a single value. The
3352 resulting value is the same type as its operands.</p>
3353
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3354</div>
3355
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3356<!-- _______________________________________________________________________ -->
3357<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3358Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3359
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3360<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3361
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3362<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3363<pre>
3364 &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]3365</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3366
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3367<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3368<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3369 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3370
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3371<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3372<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3373 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3374 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3375
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3376<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3377<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3378 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3379 is (statically or dynamically) negative or equal to or larger than the number
3380 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3381 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3382 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3383
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3384<h5>Example:</h5>
3385<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3386 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3387 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3388 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3389 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3390 &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]3391</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3392
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3393</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3394
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3395<!-- _______________________________________________________________________ -->
3396<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3397Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3398
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3399<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3400
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3401<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3402<pre>
3403 &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]3404</pre>
3405
3406<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3407<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3408 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3409
3410<h5>Arguments:</h5>
3411<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3412 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3413 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3414
3415<h5>Semantics:</h5>
3416<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3417 significant bits of the result will be filled with zero bits after the shift.
3418 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3419 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3420 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3421 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3422
3423<h5>Example:</h5>
3424<pre>
3425 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3426 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3427 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3428 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3429 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3430 &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]3431</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3432
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3433</div>
3434
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3435<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3436<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3437Instruction</a> </div>
3438<div class="doc_text">
3439
3440<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3441<pre>
3442 &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]3443</pre>
3444
3445<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3447 operand shifted to the right a specified number of bits with sign
3448 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3449
3450<h5>Arguments:</h5>
3451<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3453 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3454
3455<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3456<p>This instruction always performs an arithmetic shift right operation, The
3457 most significant bits of the result will be filled with the sign bit
3458 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3459 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3460 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3461 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3462
3463<h5>Example:</h5>
3464<pre>
3465 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3466 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3467 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3468 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3469 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3470 &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]3471</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3472
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3473</div>
3474
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3475<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3476<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3477Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3478
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3479<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3480
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3481<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3482<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3483 &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]3484</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3485
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3486<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3487<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3488 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3489
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3490<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3491<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3492 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3493 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3494
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3495<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3496<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3497
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3498<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3499 <tbody>
3500 <tr>
3501 <td>In0</td>
3502 <td>In1</td>
3503 <td>Out</td>
3504 </tr>
3505 <tr>
3506 <td>0</td>
3507 <td>0</td>
3508 <td>0</td>
3509 </tr>
3510 <tr>
3511 <td>0</td>
3512 <td>1</td>
3513 <td>0</td>
3514 </tr>
3515 <tr>
3516 <td>1</td>
3517 <td>0</td>
3518 <td>0</td>
3519 </tr>
3520 <tr>
3521 <td>1</td>
3522 <td>1</td>
3523 <td>1</td>
3524 </tr>
3525 </tbody>
3526</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3527
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3528<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3529<pre>
3530 &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]3531 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3532 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3533</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3534</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3535<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3536<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3537
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3538<div class="doc_text">
3539
3540<h5>Syntax:</h5>
3541<pre>
3542 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3543</pre>
3544
3545<h5>Overview:</h5>
3546<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3547 two operands.</p>
3548
3549<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3550<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3551 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3552 values. Both arguments must have identical types.</p>
3553
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3554<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3555<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3556
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3557<table border="1" cellspacing="0" cellpadding="4">
3558 <tbody>
3559 <tr>
3560 <td>In0</td>
3561 <td>In1</td>
3562 <td>Out</td>
3563 </tr>
3564 <tr>
3565 <td>0</td>
3566 <td>0</td>
3567 <td>0</td>
3568 </tr>
3569 <tr>
3570 <td>0</td>
3571 <td>1</td>
3572 <td>1</td>
3573 </tr>
3574 <tr>
3575 <td>1</td>
3576 <td>0</td>
3577 <td>1</td>
3578 </tr>
3579 <tr>
3580 <td>1</td>
3581 <td>1</td>
3582 <td>1</td>
3583 </tr>
3584 </tbody>
3585</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3587<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3588<pre>
3589 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3590 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3591 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3592</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3593
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3594</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3595
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3596<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3597<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3598Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3599
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3600<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3601
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3602<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3603<pre>
3604 &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]3605</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3606
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3607<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3608<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3609 its two operands. The <tt>xor</tt> is used to implement the "one's
3610 complement" operation, which is the "~" operator in C.</p>
3611
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3612<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3613<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3614 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3615 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3616
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3617<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3618<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3619
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3620<table border="1" cellspacing="0" cellpadding="4">
3621 <tbody>
3622 <tr>
3623 <td>In0</td>
3624 <td>In1</td>
3625 <td>Out</td>
3626 </tr>
3627 <tr>
3628 <td>0</td>
3629 <td>0</td>
3630 <td>0</td>
3631 </tr>
3632 <tr>
3633 <td>0</td>
3634 <td>1</td>
3635 <td>1</td>
3636 </tr>
3637 <tr>
3638 <td>1</td>
3639 <td>0</td>
3640 <td>1</td>
3641 </tr>
3642 <tr>
3643 <td>1</td>
3644 <td>1</td>
3645 <td>0</td>
3646 </tr>
3647 </tbody>
3648</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3650<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3651<pre>
3652 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3653 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3654 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3655 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3656</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3657
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3658</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3659
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3660<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3661<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3662 <a name="vectorops">Vector Operations</a>
3663</div>
3664
3665<div class="doc_text">
3666
3667<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3668 target-independent manner. These instructions cover the element-access and
3669 vector-specific operations needed to process vectors effectively. While LLVM
3670 does directly support these vector operations, many sophisticated algorithms
3671 will want to use target-specific intrinsics to take full advantage of a
3672 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3673
3674</div>
3675
3676<!-- _______________________________________________________________________ -->
3677<div class="doc_subsubsection">
3678 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3679</div>
3680
3681<div class="doc_text">
3682
3683<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3684<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3685 &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]3686</pre>
3687
3688<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3689<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3690 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3691
3692
3693<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3694<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3695 of <a href="#t_vector">vector</a> type. The second operand is an index
3696 indicating the position from which to extract the element. The index may be
3697 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3698
3699<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3700<p>The result is a scalar of the same type as the element type of
3701 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3702 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3703 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3704
3705<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3706<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3707 &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]3708</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3709
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3710</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3711
3712<!-- _______________________________________________________________________ -->
3713<div class="doc_subsubsection">
3714 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3715</div>
3716
3717<div class="doc_text">
3718
3719<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3720<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]3721 &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]3722</pre>
3723
3724<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3725<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3726 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3727
3728<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3729<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3730 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3731 whose type must equal the element type of the first operand. The third
3732 operand is an index indicating the position at which to insert the value.
3733 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3734
3735<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3736<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3737 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3738 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3739 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3740
3741<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3742<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3743 &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]3744</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3745
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3746</div>
3747
3748<!-- _______________________________________________________________________ -->
3749<div class="doc_subsubsection">
3750 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3751</div>
3752
3753<div class="doc_text">
3754
3755<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3756<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3757 &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]3758</pre>
3759
3760<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3761<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3762 from two input vectors, returning a vector with the same element type as the
3763 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3764
3765<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3766<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3767 with types that match each other. The third argument is a shuffle mask whose
3768 element type is always 'i32'. The result of the instruction is a vector
3769 whose length is the same as the shuffle mask and whose element type is the
3770 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3771
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3772<p>The shuffle mask operand is required to be a constant vector with either
3773 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3774
3775<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3776<p>The elements of the two input vectors are numbered from left to right across
3777 both of the vectors. The shuffle mask operand specifies, for each element of
3778 the result vector, which element of the two input vectors the result element
3779 gets. The element selector may be undef (meaning "don't care") and the
3780 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3781
3782<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3783<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3784 &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]3785 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3786 &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]3787 &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.
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3788 &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]3789 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3790 &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]3791 &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]3792</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3793
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3794</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]3795
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3796<!-- ======================================================================= -->
3797<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3798 <a name="aggregateops">Aggregate Operations</a>
3799</div>
3800
3801<div class="doc_text">
3802
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3803<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3804
3805</div>
3806
3807<!-- _______________________________________________________________________ -->
3808<div class="doc_subsubsection">
3809 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3810</div>
3811
3812<div class="doc_text">
3813
3814<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3815<pre>
3816 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3817</pre>
3818
3819<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3820<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3821 or array element from an aggregate value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3822
3823<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3824<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3825 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3826 operands are constant indices to specify which value to extract in a similar
3827 manner as indices in a
3828 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3829
3830<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3831<p>The result is the value at the position in the aggregate specified by the
3832 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3833
3834<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3835<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3836 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3837</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3838
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3839</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3840
3841<!-- _______________________________________________________________________ -->
3842<div class="doc_subsubsection">
3843 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3844</div>
3845
3846<div class="doc_text">
3847
3848<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3849<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3850 &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]3851</pre>
3852
3853<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3854<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3855 array element in an aggregate.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3856
3857
3858<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3859<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3860 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3861 second operand is a first-class value to insert. The following operands are
3862 constant indices indicating the position at which to insert the value in a
3863 similar manner as indices in a
3864 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3865 value to insert must have the same type as the value identified by the
3866 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3867
3868<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3869<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3870 that of <tt>val</tt> except that the value at the position specified by the
3871 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3872
3873<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3874<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3875 &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]3876</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3877
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3878</div>
3879
3880
3881<!-- ======================================================================= -->
3882<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3883 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3884</div>
3885
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3886<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3887
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3888<p>A key design point of an SSA-based representation is how it represents
3889 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]3890 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3891 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3892
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3893</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3894
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3895<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3896<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3897 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3898</div>
3899
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3900<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3901
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3902<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3903<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3904 &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]3905</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3906
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3907<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3908<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3909 currently executing function, to be automatically released when this function
3910 returns to its caller. The object is always allocated in the generic address
3911 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3912
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3913<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3914<p>The '<tt>alloca</tt>' instruction
3915 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3916 runtime stack, returning a pointer of the appropriate type to the program.
3917 If "NumElements" is specified, it is the number of elements allocated,
3918 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3919 specified, the value result of the allocation is guaranteed to be aligned to
3920 at least that boundary. If not specified, or if zero, the target can choose
3921 to align the allocation on any convenient boundary compatible with the
3922 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3923
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3924<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3926<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]3927<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3928 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3929 memory is automatically released when the function returns. The
3930 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3931 variables that must have an address available. When the function returns
3932 (either with the <tt><a href="#i_ret">ret</a></tt>
3933 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3934 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3935
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3936<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3937<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3938 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3939 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3940 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3941 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3942</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3943
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3944</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3945
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3946<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3947<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3948Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3949
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3950<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3951
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3952<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3953<pre>
3954 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3955 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3956</pre>
3957
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3958<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3959<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3960
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3961<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3963 from which to load. The pointer must point to
3964 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3965 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3966 number or order of execution of this <tt>load</tt> with other
3967 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3968 instructions. </p>
3969
3970<p>The optional constant "align" argument specifies the alignment of the
3971 operation (that is, the alignment of the memory address). A value of 0 or an
3972 omitted "align" argument means that the operation has the preferential
3973 alignment for the target. It is the responsibility of the code emitter to
3974 ensure that the alignment information is correct. Overestimating the
3975 alignment results in an undefined behavior. Underestimating the alignment may
3976 produce less efficient code. An alignment of 1 is always safe.</p>
3977
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3978<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3979<p>The location of memory pointed to is loaded. If the value being loaded is of
3980 scalar type then the number of bytes read does not exceed the minimum number
3981 of bytes needed to hold all bits of the type. For example, loading an
3982 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3983 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3984 is undefined if the value was not originally written using a store of the
3985 same type.</p>
3986
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3987<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3988<pre>
3989 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3990 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3991 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3992</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3993
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3994</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3995
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3996<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3997<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3998Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3999
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4000<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4001
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4002<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4003<pre>
4004 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]4005 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]4006</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4007
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4008<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4009<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4010
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4011<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4012<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4013 and an address at which to store it. The type of the
4014 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4015 the <a href="#t_firstclass">first class</a> type of the
4016 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4017 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4018 or order of execution of this <tt>store</tt> with other
4019 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4020 instructions.</p>
4021
4022<p>The optional constant "align" argument specifies the alignment of the
4023 operation (that is, the alignment of the memory address). A value of 0 or an
4024 omitted "align" argument means that the operation has the preferential
4025 alignment for the target. It is the responsibility of the code emitter to
4026 ensure that the alignment information is correct. Overestimating the
4027 alignment results in an undefined behavior. Underestimating the alignment may
4028 produce less efficient code. An alignment of 1 is always safe.</p>
4029
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4030<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4031<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4032 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4033 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4034 does not exceed the minimum number of bytes needed to hold all bits of the
4035 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4036 writing a value of a type like <tt>i20</tt> with a size that is not an
4037 integral number of bytes, it is unspecified what happens to the extra bits
4038 that do not belong to the type, but they will typically be overwritten.</p>
4039
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4040<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4041<pre>
4042 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4043 store i32 3, i32* %ptr <i>; yields {void}</i>
4044 %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]4045</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4046
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4047</div>
4048
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4049<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4050<div class="doc_subsubsection">
4051 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4052</div>
4053
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4054<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4055
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4056<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4057<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4058 &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]4059 &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]4060</pre>
4061
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4062<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4063<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4064 subelement of an aggregate data structure. It performs address calculation
4065 only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4066
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4067<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4068<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4069 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4070 elements of the aggregate object are indexed. The interpretation of each
4071 index is dependent on the type being indexed into. The first index always
4072 indexes the pointer value given as the first argument, the second index
4073 indexes a value of the type pointed to (not necessarily the value directly
4074 pointed to, since the first index can be non-zero), etc. The first type
4075 indexed into must be a pointer value, subsequent types can be arrays, vectors
4076 and structs. Note that subsequent types being indexed into can never be
4077 pointers, since that would require loading the pointer before continuing
4078 calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4079
4080<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]4081 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4082 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4083 vector, integers of any width are allowed, and they are not required to be
4084 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4085
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4086<p>For example, let's consider a C code fragment and how it gets compiled to
4087 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4088
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4089<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4090<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4091struct RT {
4092 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4093 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4094 char C;
4095};
4096struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4097 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4098 double Y;
4099 struct RT Z;
4100};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4101
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4102int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4103 return &amp;s[1].Z.B[5][13];
4104}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4105</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4106</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4107
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4108<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4109
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4110<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4111<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4112%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4113%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4114
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4115define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4116entry:
4117 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4118 ret i32* %reg
4119}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4120</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4121</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4122
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4123<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4124<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]4125 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4126 }</tt>' type, a structure. The second index indexes into the third element
4127 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4128 i8 }</tt>' type, another structure. The third index indexes into the second
4129 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4130 array. The two dimensions of the array are subscripted into, yielding an
4131 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4132 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4133
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4134<p>Note that it is perfectly legal to index partially through a structure,
4135 returning a pointer to an inner element. Because of this, the LLVM code for
4136 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4137
4138<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4139 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4140 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4141 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4142 %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]4143 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4144 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4145 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4146 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4147</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4148
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4149<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4150 <tt>getelementptr</tt> is undefined if the base pointer is not an
4151 <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]4152 that would be formed by successive addition of the offsets implied by the
4153 indices to the base address with infinitely precise arithmetic are not an
4154 <i>in bounds</i> address of that allocated object.
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4155 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4156 that point into the object, plus the address one byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4157
4158<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4159 the base address with silently-wrapping two's complement arithmetic, and
4160 the result value of the <tt>getelementptr</tt> may be outside the object
4161 pointed to by the base pointer. The result value may not necessarily be
4162 used to access memory though, even if it happens to point into allocated
4163 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4164 section for more information.</p>
4165
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4166<p>The getelementptr instruction is often confusing. For some more insight into
4167 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4168
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4169<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4170<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4171 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4172 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4173 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4174 %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]4175 <i>; yields i8*:eptr</i>
4176 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4177 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4178 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4179</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4180
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4181</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4182
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4183<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4184<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4185</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4186
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4187<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4188
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4189<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4190 which all take a single operand and a type. They perform various bit
4191 conversions on the operand.</p>
4192
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4193</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4194
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4195<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4196<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4197 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4198</div>
4199<div class="doc_text">
4200
4201<h5>Syntax:</h5>
4202<pre>
4203 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4204</pre>
4205
4206<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4207<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4208 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4209
4210<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4211<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4212 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4213 size and type of the result, which must be
4214 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4215 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4216 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4217
4218<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4219<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4220 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4221 source size must be larger than the destination size, <tt>trunc</tt> cannot
4222 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4223
4224<h5>Example:</h5>
4225<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4226 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4227 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4228 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4229</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4230
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4231</div>
4232
4233<!-- _______________________________________________________________________ -->
4234<div class="doc_subsubsection">
4235 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4236</div>
4237<div class="doc_text">
4238
4239<h5>Syntax:</h5>
4240<pre>
4241 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4242</pre>
4243
4244<h5>Overview:</h5>
4245<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4246 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4247
4248
4249<h5>Arguments:</h5>
4250<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]4251 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4252 also be of <a href="#t_integer">integer</a> type. The bit size of the
4253 <tt>value</tt> must be smaller than the bit size of the destination type,
4254 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4255
4256<h5>Semantics:</h5>
4257<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]4258 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4259
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4260<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]4261
4262<h5>Example:</h5>
4263<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4264 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4265 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4266</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4267
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4268</div>
4269
4270<!-- _______________________________________________________________________ -->
4271<div class="doc_subsubsection">
4272 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4273</div>
4274<div class="doc_text">
4275
4276<h5>Syntax:</h5>
4277<pre>
4278 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4279</pre>
4280
4281<h5>Overview:</h5>
4282<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4283
4284<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4285<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4286 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4287 also be of <a href="#t_integer">integer</a> type. The bit size of the
4288 <tt>value</tt> must be smaller than the bit size of the destination type,
4289 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4290
4291<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4292<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4293 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4294 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4295
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4296<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]4297
4298<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4299<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4300 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4301 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4302</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4303
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4304</div>
4305
4306<!-- _______________________________________________________________________ -->
4307<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4308 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4309</div>
4310
4311<div class="doc_text">
4312
4313<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4314<pre>
4315 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4316</pre>
4317
4318<h5>Overview:</h5>
4319<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4320 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4321
4322<h5>Arguments:</h5>
4323<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4324 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4325 to cast it to. The size of <tt>value</tt> must be larger than the size of
4326 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4327 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4328
4329<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4330<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4331 <a href="#t_floating">floating point</a> type to a smaller
4332 <a href="#t_floating">floating point</a> type. If the value cannot fit
4333 within the destination type, <tt>ty2</tt>, then the results are
4334 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4335
4336<h5>Example:</h5>
4337<pre>
4338 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4339 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4340</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4341
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4342</div>
4343
4344<!-- _______________________________________________________________________ -->
4345<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4346 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4347</div>
4348<div class="doc_text">
4349
4350<h5>Syntax:</h5>
4351<pre>
4352 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4353</pre>
4354
4355<h5>Overview:</h5>
4356<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]4357 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4358
4359<h5>Arguments:</h5>
4360<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4361 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4362 a <a href="#t_floating">floating point</a> type to cast it to. The source
4363 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4364
4365<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4366<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4367 <a href="#t_floating">floating point</a> type to a larger
4368 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4369 used to make a <i>no-op cast</i> because it always changes bits. Use
4370 <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]4371
4372<h5>Example:</h5>
4373<pre>
4374 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4375 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4376</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4377
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4378</div>
4379
4380<!-- _______________________________________________________________________ -->
4381<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4382 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4383</div>
4384<div class="doc_text">
4385
4386<h5>Syntax:</h5>
4387<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4388 &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]4389</pre>
4390
4391<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4392<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4393 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4394
4395<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4396<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4397 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4398 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4399 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4400 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4401
4402<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4403<p>The '<tt>fptoui</tt>' instruction converts its
4404 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4405 towards zero) unsigned integer value. If the value cannot fit
4406 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4407
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4408<h5>Example:</h5>
4409<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4410 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4411 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4412 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4413</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4414
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4415</div>
4416
4417<!-- _______________________________________________________________________ -->
4418<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4419 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4420</div>
4421<div class="doc_text">
4422
4423<h5>Syntax:</h5>
4424<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4425 &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]4426</pre>
4427
4428<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4429<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4430 <a href="#t_floating">floating point</a> <tt>value</tt> to
4431 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4432
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4433<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4434<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4435 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4436 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4437 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4438 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4439
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4440<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4441<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4442 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4443 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4444 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4445
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4446<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4447<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4448 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4449 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4450 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4451</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4452
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4453</div>
4454
4455<!-- _______________________________________________________________________ -->
4456<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4457 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4458</div>
4459<div class="doc_text">
4460
4461<h5>Syntax:</h5>
4462<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4463 &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]4464</pre>
4465
4466<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4467<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4468 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4469
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4470<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4471<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]4472 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4473 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4474 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4475 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4476
4477<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4478<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4479 integer quantity and converts it to the corresponding floating point
4480 value. If the value cannot fit in the floating point value, the results are
4481 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4482
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4483<h5>Example:</h5>
4484<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4485 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4486 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4487</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4488
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4489</div>
4490
4491<!-- _______________________________________________________________________ -->
4492<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4493 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4494</div>
4495<div class="doc_text">
4496
4497<h5>Syntax:</h5>
4498<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4499 &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]4500</pre>
4501
4502<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4503<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4504 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4505
4506<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4507<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]4508 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4509 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4510 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4511 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4512
4513<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4514<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4515 quantity and converts it to the corresponding floating point value. If the
4516 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4517
4518<h5>Example:</h5>
4519<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4520 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4521 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4522</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4523
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4524</div>
4525
4526<!-- _______________________________________________________________________ -->
4527<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4528 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4529</div>
4530<div class="doc_text">
4531
4532<h5>Syntax:</h5>
4533<pre>
4534 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4535</pre>
4536
4537<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4538<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4539 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4540
4541<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4542<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4543 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4544 <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]4545
4546<h5>Semantics:</h5>
4547<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4548 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4549 truncating or zero extending that value to the size of the integer type. If
4550 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4551 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4552 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4553 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4554
4555<h5>Example:</h5>
4556<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4557 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4558 %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]4559</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4560
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4561</div>
4562
4563<!-- _______________________________________________________________________ -->
4564<div class="doc_subsubsection">
4565 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4566</div>
4567<div class="doc_text">
4568
4569<h5>Syntax:</h5>
4570<pre>
4571 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4572</pre>
4573
4574<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4575<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4576 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4577
4578<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4579<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4580 value to cast, and a type to cast it to, which must be a
4581 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4582
4583<h5>Semantics:</h5>
4584<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4585 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4586 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4587 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4588 than the size of a pointer then a zero extension is done. If they are the
4589 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4590
4591<h5>Example:</h5>
4592<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4593 %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]4594 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4595 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4596</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4597
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4598</div>
4599
4600<!-- _______________________________________________________________________ -->
4601<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4602 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4603</div>
4604<div class="doc_text">
4605
4606<h5>Syntax:</h5>
4607<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4608 &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]4609</pre>
4610
4611<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4612<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4613 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4614
4615<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4616<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4617 non-aggregate first class value, and a type to cast it to, which must also be
4618 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4619 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4620 identical. If the source type is a pointer, the destination type must also be
4621 a pointer. This instruction supports bitwise conversion of vectors to
4622 integers and to vectors of other types (as long as they have the same
4623 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4624
4625<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4626<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4627 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4628 this conversion. The conversion is done as if the <tt>value</tt> had been
4629 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4630 be converted to other pointer types with this instruction. To convert
4631 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4632 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4633
4634<h5>Example:</h5>
4635<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4636 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4637 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4638 %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]4639</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4640
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4641</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4642
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4643<!-- ======================================================================= -->
4644<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4645
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4646<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4647
4648<p>The instructions in this category are the "miscellaneous" instructions, which
4649 defy better classification.</p>
4650
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4651</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4652
4653<!-- _______________________________________________________________________ -->
4654<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4655</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4656
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4657<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4658
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4659<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4660<pre>
4661 &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]4662</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4663
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4664<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4665<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4666 boolean values based on comparison of its two integer, integer vector, or
4667 pointer operands.</p>
4668
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4669<h5>Arguments:</h5>
4670<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4671 the condition code indicating the kind of comparison to perform. It is not a
4672 value, just a keyword. The possible condition code are:</p>
4673
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4674<ol>
4675 <li><tt>eq</tt>: equal</li>
4676 <li><tt>ne</tt>: not equal </li>
4677 <li><tt>ugt</tt>: unsigned greater than</li>
4678 <li><tt>uge</tt>: unsigned greater or equal</li>
4679 <li><tt>ult</tt>: unsigned less than</li>
4680 <li><tt>ule</tt>: unsigned less or equal</li>
4681 <li><tt>sgt</tt>: signed greater than</li>
4682 <li><tt>sge</tt>: signed greater or equal</li>
4683 <li><tt>slt</tt>: signed less than</li>
4684 <li><tt>sle</tt>: signed less or equal</li>
4685</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4686
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4687<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4688 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4689 typed. They must also be identical types.</p>
4690
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4691<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4692<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4693 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4694 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]4695 result, as follows:</p>
4696
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4697<ol>
4698 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4699 <tt>false</tt> otherwise. No sign interpretation is necessary or
4700 performed.</li>
4701
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4702 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4703 <tt>false</tt> otherwise. No sign interpretation is necessary or
4704 performed.</li>
4705
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4706 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4707 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4708
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4709 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4710 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4711 to <tt>op2</tt>.</li>
4712
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4713 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4714 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4715
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4716 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4717 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4718
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4719 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4720 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4721
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4722 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4723 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4724 to <tt>op2</tt>.</li>
4725
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4726 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4727 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4728
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4729 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4730 <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]4731</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4732
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4733<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4734 values are compared as if they were integers.</p>
4735
4736<p>If the operands are integer vectors, then they are compared element by
4737 element. The result is an <tt>i1</tt> vector with the same number of elements
4738 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4739
4740<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741<pre>
4742 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4743 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4744 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4745 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4746 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4747 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4748</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4749
4750<p>Note that the code generator does not yet support vector types with
4751 the <tt>icmp</tt> instruction.</p>
4752
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4753</div>
4754
4755<!-- _______________________________________________________________________ -->
4756<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4757</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4758
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4759<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4760
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4761<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4762<pre>
4763 &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]4764</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4765
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4766<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4767<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4768 values based on comparison of its operands.</p>
4769
4770<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]4771(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4772
4773<p>If the operands are floating point vectors, then the result type is a vector
4774 of boolean with the same number of elements as the operands being
4775 compared.</p>
4776
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4777<h5>Arguments:</h5>
4778<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4779 the condition code indicating the kind of comparison to perform. It is not a
4780 value, just a keyword. The possible condition code are:</p>
4781
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4782<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4783 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4784 <li><tt>oeq</tt>: ordered and equal</li>
4785 <li><tt>ogt</tt>: ordered and greater than </li>
4786 <li><tt>oge</tt>: ordered and greater than or equal</li>
4787 <li><tt>olt</tt>: ordered and less than </li>
4788 <li><tt>ole</tt>: ordered and less than or equal</li>
4789 <li><tt>one</tt>: ordered and not equal</li>
4790 <li><tt>ord</tt>: ordered (no nans)</li>
4791 <li><tt>ueq</tt>: unordered or equal</li>
4792 <li><tt>ugt</tt>: unordered or greater than </li>
4793 <li><tt>uge</tt>: unordered or greater than or equal</li>
4794 <li><tt>ult</tt>: unordered or less than </li>
4795 <li><tt>ule</tt>: unordered or less than or equal</li>
4796 <li><tt>une</tt>: unordered or not equal</li>
4797 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4798 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4799</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4800
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4801<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4802 <i>unordered</i> means that either operand may be a QNAN.</p>
4803
4804<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4805 a <a href="#t_floating">floating point</a> type or
4806 a <a href="#t_vector">vector</a> of floating point type. They must have
4807 identical types.</p>
4808
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4809<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4810<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4811 according to the condition code given as <tt>cond</tt>. If the operands are
4812 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4813 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4814 follows:</p>
4815
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4816<ol>
4817 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4818
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4819 <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]4820 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4821
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4822 <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]4823 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4824
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4825 <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]4826 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4827
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4828 <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]4829 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4830
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4831 <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]4832 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4833
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4834 <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]4835 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4836
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4837 <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]4838
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4839 <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]4840 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4841
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4842 <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]4843 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4844
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4845 <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]4846 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4847
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4848 <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]4849 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4850
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4851 <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]4852 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4853
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4854 <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]4855 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4856
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4857 <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]4858
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4859 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4860</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4861
4862<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4863<pre>
4864 &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]4865 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4866 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4867 &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]4868</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4869
4870<p>Note that the code generator does not yet support vector types with
4871 the <tt>fcmp</tt> instruction.</p>
4872
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4873</div>
4874
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4875<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]4876<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4877 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4878</div>
4879
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4880<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4881
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4882<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4883<pre>
4884 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4885</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4886
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4887<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4888<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4889 SSA graph representing the function.</p>
4890
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4891<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4892<p>The type of the incoming values is specified with the first type field. After
4893 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4894 one pair for each predecessor basic block of the current block. Only values
4895 of <a href="#t_firstclass">first class</a> type may be used as the value
4896 arguments to the PHI node. Only labels may be used as the label
4897 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4898
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4899<p>There must be no non-phi instructions between the start of a basic block and
4900 the PHI instructions: i.e. PHI instructions must be first in a basic
4901 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4902
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4903<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4904 occur on the edge from the corresponding predecessor block to the current
4905 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4906 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]4907
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4908<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4909<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4910 specified by the pair corresponding to the predecessor basic block that
4911 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4912
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4913<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4914<pre>
4915Loop: ; Infinite loop that counts from 0 on up...
4916 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4917 %nextindvar = add i32 %indvar, 1
4918 br label %Loop
4919</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4920
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4921</div>
4922
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4923<!-- _______________________________________________________________________ -->
4924<div class="doc_subsubsection">
4925 <a name="i_select">'<tt>select</tt>' Instruction</a>
4926</div>
4927
4928<div class="doc_text">
4929
4930<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4931<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4932 &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>
4933
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4934 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4935</pre>
4936
4937<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4938<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4939 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4940
4941
4942<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4943<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4944 values indicating the condition, and two values of the
4945 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4946 vectors and the condition is a scalar, then entire vectors are selected, not
4947 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4948
4949<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4950<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4951 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4952
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4953<p>If the condition is a vector of i1, then the value arguments must be vectors
4954 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4955
4956<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4957<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4958 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4959</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4960
4961<p>Note that the code generator does not yet support conditions
4962 with vector type.</p>
4963
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4964</div>
4965
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]4966<!-- _______________________________________________________________________ -->
4967<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4968 <a name="i_call">'<tt>call</tt>' Instruction</a>
4969</div>
4970
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4971<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4972
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4973<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4974<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]4975 &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]4976</pre>
4977
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4978<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4979<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4980
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4981<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4982<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4983
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4984<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4985 <li>The optional "tail" marker indicates whether the callee function accesses
4986 any allocas or varargs in the caller. If the "tail" marker is present,
4987 the function call is eligible for tail call optimization. Note that calls
4988 may be marked "tail" even if they do not occur before
4989 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4990
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4991 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4992 convention</a> the call should use. If none is specified, the call
4993 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4994
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4995 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4996 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4997 '<tt>inreg</tt>' attributes are valid here.</li>
4998
4999 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5000 type of the return value. Functions that return no value are marked
5001 <tt><a href="#t_void">void</a></tt>.</li>
5002
5003 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5004 being invoked. The argument types must match the types implied by this
5005 signature. This type can be omitted if the function is not varargs and if
5006 the function type does not return a pointer to a function.</li>
5007
5008 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5009 be invoked. In most cases, this is a direct function invocation, but
5010 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5011 to function value.</li>
5012
5013 <li>'<tt>function args</tt>': argument list whose types match the function
5014 signature argument types. All arguments must be of
5015 <a href="#t_firstclass">first class</a> type. If the function signature
5016 indicates the function accepts a variable number of arguments, the extra
5017 arguments can be specified.</li>
5018
5019 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5020 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5021 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5022</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5023
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5024<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5025<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5026 a specified function, with its incoming arguments bound to the specified
5027 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5028 function, control flow continues with the instruction after the function
5029 call, and the return value of the function is bound to the result
5030 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5031
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5032<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5033<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5034 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5035 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5036 %X = tail call i32 @foo() <i>; yields i32</i>
5037 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5038 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5039
5040 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5041 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5042 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5043 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5044 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5045 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5046</pre>
5047
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5048<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5049standard C99 library as being the C99 library functions, and may perform
5050optimizations or generate code for them under that assumption. This is
5051something we'd like to change in the future to provide better support for
5052freestanding environments and non-C-based langauges.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5053
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5054</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5055
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5056<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5057<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5058 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5059</div>
5060
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5061<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5062
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5063<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5064<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5065 &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]5066</pre>
5067
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5068<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5069<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5070 the "variable argument" area of a function call. It is used to implement the
5071 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5072
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5073<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5074<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5075 argument. It returns a value of the specified argument type and increments
5076 the <tt>va_list</tt> to point to the next argument. The actual type
5077 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5078
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5079<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5081 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5082 to the next argument. For more information, see the variable argument
5083 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5084
5085<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]5086 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5087 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5088
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5089<p><tt>va_arg</tt> is an LLVM instruction instead of
5090 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5091 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5092
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5093<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5094<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5095
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5096<p>Note that the code generator does not yet fully support va_arg on many
5097 targets. Also, it does not currently support va_arg with aggregate types on
5098 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5099
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5100</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5101
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5102<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5103<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5104<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5105
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5106<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5107
5108<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5109 well known names and semantics and are required to follow certain
5110 restrictions. Overall, these intrinsics represent an extension mechanism for
5111 the LLVM language that does not require changing all of the transformations
5112 in LLVM when adding to the language (or the bitcode reader/writer, the
5113 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5114
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5115<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5116 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5117 begin with this prefix. Intrinsic functions must always be external
5118 functions: you cannot define the body of intrinsic functions. Intrinsic
5119 functions may only be used in call or invoke instructions: it is illegal to
5120 take the address of an intrinsic function. Additionally, because intrinsic
5121 functions are part of the LLVM language, it is required if any are added that
5122 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5123
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5124<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5125 family of functions that perform the same operation but on different data
5126 types. Because LLVM can represent over 8 million different integer types,
5127 overloading is used commonly to allow an intrinsic function to operate on any
5128 integer type. One or more of the argument types or the result type can be
5129 overloaded to accept any integer type. Argument types may also be defined as
5130 exactly matching a previous argument's type or the result type. This allows
5131 an intrinsic function which accepts multiple arguments, but needs all of them
5132 to be of the same type, to only be overloaded with respect to a single
5133 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5134
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5135<p>Overloaded intrinsics will have the names of its overloaded argument types
5136 encoded into its function name, each preceded by a period. Only those types
5137 which are overloaded result in a name suffix. Arguments whose type is matched
5138 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5139 can take an integer of any width and returns an integer of exactly the same
5140 integer width. This leads to a family of functions such as
5141 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5142 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5143 suffix is required. Because the argument's type is matched against the return
5144 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5145
5146<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5147 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5148
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5149</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5150
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5151<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5152<div class="doc_subsection">
5153 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5154</div>
5155
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5156<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5157
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5158<p>Variable argument support is defined in LLVM with
5159 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5160 intrinsic functions. These functions are related to the similarly named
5161 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5162
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5163<p>All of these functions operate on arguments that use a target-specific value
5164 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5165 not define what this type is, so all transformations should be prepared to
5166 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5167
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5168<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]5169 instruction and the variable argument handling intrinsic functions are
5170 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5171
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5172<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5173<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5174define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5175 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5176 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5177 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5178 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5179
5180 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5181 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5182
5183 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5184 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5185 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5186 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5187 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5188
5189 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5190 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5191 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5192}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5193
5194declare void @llvm.va_start(i8*)
5195declare void @llvm.va_copy(i8*, i8*)
5196declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5197</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5198</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5199
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5200</div>
5201
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5202<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5203<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5204 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5205</div>
5206
5207
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5208<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5209
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5210<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5211<pre>
5212 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5213</pre>
5214
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5215<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5216<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5217 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]5218
5219<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5220<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]5221
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5222<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5223<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]5224 macro available in C. In a target-dependent way, it initializes
5225 the <tt>va_list</tt> element to which the argument points, so that the next
5226 call to <tt>va_arg</tt> will produce the first variable argument passed to
5227 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5228 need to know the last argument of the function as the compiler can figure
5229 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5230
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5231</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5232
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5233<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5234<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5235 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5236</div>
5237
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5238<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5239
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5240<h5>Syntax:</h5>
5241<pre>
5242 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5243</pre>
5244
5245<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5246<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5247 which has been initialized previously
5248 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5249 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5250
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5251<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5252<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]5253
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5254<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5255<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]5256 macro available in C. In a target-dependent way, it destroys
5257 the <tt>va_list</tt> element to which the argument points. Calls
5258 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5259 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5260 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5261
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5262</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5263
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5264<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5265<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5266 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5267</div>
5268
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5269<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5270
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5271<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5272<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5273 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5274</pre>
5275
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5276<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5277<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5278 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5279
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5280<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5281<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]5282 The second argument is a pointer to a <tt>va_list</tt> element to copy
5283 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5284
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5285<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5286<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]5287 macro available in C. In a target-dependent way, it copies the
5288 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5289 element. This intrinsic is necessary because
5290 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5291 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5292
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5293</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5294
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5295<!-- ======================================================================= -->
5296<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5297 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5298</div>
5299
5300<div class="doc_text">
5301
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5302<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5303Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5304intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5305roots on the stack</a>, as well as garbage collector implementations that
5306require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5307barriers. Front-ends for type-safe garbage collected languages should generate
5308these intrinsics to make use of the LLVM garbage collectors. For more details,
5309see <a href="GarbageCollection.html">Accurate Garbage Collection with
5310LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5311
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5312<p>The garbage collection intrinsics only operate on objects in the generic
5313 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5314
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5315</div>
5316
5317<!-- _______________________________________________________________________ -->
5318<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5319 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5320</div>
5321
5322<div class="doc_text">
5323
5324<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5325<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5326 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5327</pre>
5328
5329<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5330<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]5331 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5332
5333<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5334<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5335 root pointer. The second pointer (which must be either a constant or a
5336 global value address) contains the meta-data to be associated with the
5337 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5338
5339<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5340<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]5341 location. At compile-time, the code generator generates information to allow
5342 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5343 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5344 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5345
5346</div>
5347
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5348<!-- _______________________________________________________________________ -->
5349<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5350 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5351</div>
5352
5353<div class="doc_text">
5354
5355<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5356<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5357 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5358</pre>
5359
5360<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5361<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5362 locations, allowing garbage collector implementations that require read
5363 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5364
5365<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5366<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]5367 allocated from the garbage collector. The first object is a pointer to the
5368 start of the referenced object, if needed by the language runtime (otherwise
5369 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5370
5371<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5372<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5373 instruction, but may be replaced with substantially more complex code by the
5374 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5375 may only be used in a function which <a href="#gc">specifies a GC
5376 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5377
5378</div>
5379
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5380<!-- _______________________________________________________________________ -->
5381<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5382 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5383</div>
5384
5385<div class="doc_text">
5386
5387<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5388<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5389 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5390</pre>
5391
5392<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5393<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5394 locations, allowing garbage collector implementations that require write
5395 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5396
5397<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5398<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]5399 object to store it to, and the third is the address of the field of Obj to
5400 store to. If the runtime does not require a pointer to the object, Obj may
5401 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5402
5403<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5404<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5405 instruction, but may be replaced with substantially more complex code by the
5406 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5407 may only be used in a function which <a href="#gc">specifies a GC
5408 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5409
5410</div>
5411
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5412<!-- ======================================================================= -->
5413<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5414 <a name="int_codegen">Code Generator Intrinsics</a>
5415</div>
5416
5417<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5418
5419<p>These intrinsics are provided by LLVM to expose special features that may
5420 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5421
5422</div>
5423
5424<!-- _______________________________________________________________________ -->
5425<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5426 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5427</div>
5428
5429<div class="doc_text">
5430
5431<h5>Syntax:</h5>
5432<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5433 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5434</pre>
5435
5436<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5437<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5438 target-specific value indicating the return address of the current function
5439 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5440
5441<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5442<p>The argument to this intrinsic indicates which function to return the address
5443 for. Zero indicates the calling function, one indicates its caller, etc.
5444 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5445
5446<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5447<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5448 indicating the return address of the specified call frame, or zero if it
5449 cannot be identified. The value returned by this intrinsic is likely to be
5450 incorrect or 0 for arguments other than zero, so it should only be used for
5451 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5452
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5453<p>Note that calling this intrinsic does not prevent function inlining or other
5454 aggressive transformations, so the value returned may not be that of the
5455 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5456
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5457</div>
5458
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5459<!-- _______________________________________________________________________ -->
5460<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5461 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5462</div>
5463
5464<div class="doc_text">
5465
5466<h5>Syntax:</h5>
5467<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5468 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5469</pre>
5470
5471<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5472<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5473 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5474
5475<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5476<p>The argument to this intrinsic indicates which function to return the frame
5477 pointer for. Zero indicates the calling function, one indicates its caller,
5478 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5479
5480<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5481<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5482 indicating the frame address of the specified call frame, or zero if it
5483 cannot be identified. The value returned by this intrinsic is likely to be
5484 incorrect or 0 for arguments other than zero, so it should only be used for
5485 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5486
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5487<p>Note that calling this intrinsic does not prevent function inlining or other
5488 aggressive transformations, so the value returned may not be that of the
5489 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5490
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5491</div>
5492
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5493<!-- _______________________________________________________________________ -->
5494<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5495 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5496</div>
5497
5498<div class="doc_text">
5499
5500<h5>Syntax:</h5>
5501<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5502 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5503</pre>
5504
5505<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5506<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5507 of the function stack, for use
5508 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5509 useful for implementing language features like scoped automatic variable
5510 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5511
5512<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5513<p>This intrinsic returns a opaque pointer value that can be passed
5514 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5515 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5516 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5517 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5518 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5519 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5520
5521</div>
5522
5523<!-- _______________________________________________________________________ -->
5524<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5525 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5526</div>
5527
5528<div class="doc_text">
5529
5530<h5>Syntax:</h5>
5531<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5532 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5533</pre>
5534
5535<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5536<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5537 the function stack to the state it was in when the
5538 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5539 executed. This is useful for implementing language features like scoped
5540 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5541
5542<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5543<p>See the description
5544 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5545
5546</div>
5547
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5548<!-- _______________________________________________________________________ -->
5549<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5550 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5551</div>
5552
5553<div class="doc_text">
5554
5555<h5>Syntax:</h5>
5556<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5557 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]5558</pre>
5559
5560<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5561<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5562 insert a prefetch instruction if supported; otherwise, it is a noop.
5563 Prefetches have no effect on the behavior of the program but can change its
5564 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5565
5566<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5567<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5568 specifier determining if the fetch should be for a read (0) or write (1),
5569 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5570 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5571 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5572
5573<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5574<p>This intrinsic does not modify the behavior of the program. In particular,
5575 prefetches cannot trap and do not produce a value. On targets that support
5576 this intrinsic, the prefetch can provide hints to the processor cache for
5577 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5578
5579</div>
5580
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5581<!-- _______________________________________________________________________ -->
5582<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5583 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5584</div>
5585
5586<div class="doc_text">
5587
5588<h5>Syntax:</h5>
5589<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5590 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5591</pre>
5592
5593<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5594<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5595 Counter (PC) in a region of code to simulators and other tools. The method
5596 is target specific, but it is expected that the marker will use exported
5597 symbols to transmit the PC of the marker. The marker makes no guarantees
5598 that it will remain with any specific instruction after optimizations. It is
5599 possible that the presence of a marker will inhibit optimizations. The
5600 intended use is to be inserted after optimizations to allow correlations of
5601 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5602
5603<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5604<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5605
5606<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5607<p>This intrinsic does not modify the behavior of the program. Backends that do
5608 not support this intrinisic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5609
5610</div>
5611
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5612<!-- _______________________________________________________________________ -->
5613<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5614 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5615</div>
5616
5617<div class="doc_text">
5618
5619<h5>Syntax:</h5>
5620<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5621 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5622</pre>
5623
5624<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5625<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5626 counter register (or similar low latency, high accuracy clocks) on those
5627 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5628 should map to RPCC. As the backing counters overflow quickly (on the order
5629 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5630
5631<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5632<p>When directly supported, reading the cycle counter should not modify any
5633 memory. Implementations are allowed to either return a application specific
5634 value or a system wide value. On backends without support, this is lowered
5635 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5636
5637</div>
5638
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5639<!-- ======================================================================= -->
5640<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5641 <a name="int_libc">Standard C Library Intrinsics</a>
5642</div>
5643
5644<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5645
5646<p>LLVM provides intrinsics for a few important standard C library functions.
5647 These intrinsics allow source-language front-ends to pass information about
5648 the alignment of the pointer arguments to the code generator, providing
5649 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5650
5651</div>
5652
5653<!-- _______________________________________________________________________ -->
5654<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5655 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5656</div>
5657
5658<div class="doc_text">
5659
5660<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5661<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5662 integer bit width. Not all targets support all bit widths however.</p>
5663
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5664<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5665 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5666 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5667 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5668 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5669 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5670 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5671 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5672 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5673</pre>
5674
5675<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5676<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5677 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5678
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5679<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5680 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5681
5682<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5683<p>The first argument is a pointer to the destination, the second is a pointer
5684 to the source. The third argument is an integer argument specifying the
5685 number of bytes to copy, and the fourth argument is the alignment of the
5686 source and destination locations.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5687
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5688<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5689 then the caller guarantees that both the source and destination pointers are
5690 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5691
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5692<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5693<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5694 source location to the destination location, which are not allowed to
5695 overlap. It copies "len" bytes of memory over. If the argument is known to
5696 be aligned to some boundary, this can be specified as the fourth argument,
5697 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5698
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5699</div>
5700
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5701<!-- _______________________________________________________________________ -->
5702<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5703 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5704</div>
5705
5706<div class="doc_text">
5707
5708<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5709<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]5710 width. Not all targets support all bit widths however.</p>
5711
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5712<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5713 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5714 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5715 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5716 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5717 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5718 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5719 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5720 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5721</pre>
5722
5723<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5724<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5725 source location to the destination location. It is similar to the
5726 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5727 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5728
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5729<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5730 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5731
5732<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5733<p>The first argument is a pointer to the destination, the second is a pointer
5734 to the source. The third argument is an integer argument specifying the
5735 number of bytes to copy, and the fourth argument is the alignment of the
5736 source and destination locations.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5737
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5738<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5739 then the caller guarantees that the source and destination pointers are
5740 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5741
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5742<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5743<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5744 source location to the destination location, which may overlap. It copies
5745 "len" bytes of memory over. If the argument is known to be aligned to some
5746 boundary, this can be specified as the fourth argument, otherwise it should
5747 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5748
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5749</div>
5750
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5751<!-- _______________________________________________________________________ -->
5752<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5753 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5754</div>
5755
5756<div class="doc_text">
5757
5758<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5759<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]5760 width. Not all targets support all bit widths however.</p>
5761
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5762<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5763 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5764 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5765 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5766 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5767 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5768 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5769 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5770 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5771</pre>
5772
5773<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5774<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5775 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5776
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5777<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5778 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5779
5780<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5781<p>The first argument is a pointer to the destination to fill, the second is the
5782 byte value to fill it with, the third argument is an integer argument
5783 specifying the number of bytes to fill, and the fourth argument is the known
5784 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5785
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5786<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5787 then the caller guarantees that the destination pointer is aligned to that
5788 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5789
5790<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5791<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5792 at the destination location. If the argument is known to be aligned to some
5793 boundary, this can be specified as the fourth argument, otherwise it should
5794 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5795
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5796</div>
5797
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5798<!-- _______________________________________________________________________ -->
5799<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5800 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5801</div>
5802
5803<div class="doc_text">
5804
5805<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5806<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5807 floating point or vector of floating point type. Not all targets support all
5808 types however.</p>
5809
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5810<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5811 declare float @llvm.sqrt.f32(float %Val)
5812 declare double @llvm.sqrt.f64(double %Val)
5813 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5814 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5815 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5816</pre>
5817
5818<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5819<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5820 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5821 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5822 behavior for negative numbers other than -0.0 (which allows for better
5823 optimization, because there is no need to worry about errno being
5824 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]5825
5826<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5827<p>The argument and return value are floating point numbers of the same
5828 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5829
5830<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5831<p>This function returns the sqrt of the specified operand if it is a
5832 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5833
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5834</div>
5835
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5836<!-- _______________________________________________________________________ -->
5837<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5838 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5839</div>
5840
5841<div class="doc_text">
5842
5843<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5844<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5845 floating point or vector of floating point type. Not all targets support all
5846 types however.</p>
5847
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5848<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5849 declare float @llvm.powi.f32(float %Val, i32 %power)
5850 declare double @llvm.powi.f64(double %Val, i32 %power)
5851 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5852 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5853 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5854</pre>
5855
5856<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5857<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5858 specified (positive or negative) power. The order of evaluation of
5859 multiplications is not defined. When a vector of floating point type is
5860 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5861
5862<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5863<p>The second argument is an integer power, and the first is a value to raise to
5864 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5865
5866<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5867<p>This function returns the first value raised to the second power with an
5868 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5869
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5870</div>
5871
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5872<!-- _______________________________________________________________________ -->
5873<div class="doc_subsubsection">
5874 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5875</div>
5876
5877<div class="doc_text">
5878
5879<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5880<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5881 floating point or vector of floating point type. Not all targets support all
5882 types however.</p>
5883
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5884<pre>
5885 declare float @llvm.sin.f32(float %Val)
5886 declare double @llvm.sin.f64(double %Val)
5887 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5888 declare fp128 @llvm.sin.f128(fp128 %Val)
5889 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5890</pre>
5891
5892<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5893<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5894
5895<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5896<p>The argument and return value are floating point numbers of the same
5897 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5898
5899<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5900<p>This function returns the sine of the specified operand, returning the same
5901 values as the libm <tt>sin</tt> functions would, and handles error conditions
5902 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5903
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5904</div>
5905
5906<!-- _______________________________________________________________________ -->
5907<div class="doc_subsubsection">
5908 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5909</div>
5910
5911<div class="doc_text">
5912
5913<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5914<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5915 floating point or vector of floating point type. Not all targets support all
5916 types however.</p>
5917
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5918<pre>
5919 declare float @llvm.cos.f32(float %Val)
5920 declare double @llvm.cos.f64(double %Val)
5921 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5922 declare fp128 @llvm.cos.f128(fp128 %Val)
5923 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5924</pre>
5925
5926<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5927<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5928
5929<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5930<p>The argument and return value are floating point numbers of the same
5931 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5932
5933<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5934<p>This function returns the cosine of the specified operand, returning the same
5935 values as the libm <tt>cos</tt> functions would, and handles error conditions
5936 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5937
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5938</div>
5939
5940<!-- _______________________________________________________________________ -->
5941<div class="doc_subsubsection">
5942 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5943</div>
5944
5945<div class="doc_text">
5946
5947<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5948<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5949 floating point or vector of floating point type. Not all targets support all
5950 types however.</p>
5951
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5952<pre>
5953 declare float @llvm.pow.f32(float %Val, float %Power)
5954 declare double @llvm.pow.f64(double %Val, double %Power)
5955 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5956 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5957 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5958</pre>
5959
5960<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5961<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5962 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5963
5964<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5965<p>The second argument is a floating point power, and the first is a value to
5966 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5967
5968<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5969<p>This function returns the first value raised to the second power, returning
5970 the same values as the libm <tt>pow</tt> functions would, and handles error
5971 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5972
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5973</div>
5974
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5975<!-- ======================================================================= -->
5976<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5977 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5978</div>
5979
5980<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5981
5982<p>LLVM provides intrinsics for a few important bit manipulation operations.
5983 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5984
5985</div>
5986
5987<!-- _______________________________________________________________________ -->
5988<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5989 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5990</div>
5991
5992<div class="doc_text">
5993
5994<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5995<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5996 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5997
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5998<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5999 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6000 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6001 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6002</pre>
6003
6004<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6005<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6006 values with an even number of bytes (positive multiple of 16 bits). These
6007 are useful for performing operations on data that is not in the target's
6008 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6009
6010<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6011<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6012 and low byte of the input i16 swapped. Similarly,
6013 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6014 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6015 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6016 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6017 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6018 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6019
6020</div>
6021
6022<!-- _______________________________________________________________________ -->
6023<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6024 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6025</div>
6026
6027<div class="doc_text">
6028
6029<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6030<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]6031 width. Not all targets support all bit widths however.</p>
6032
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6033<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6034 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6035 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6036 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6037 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6038 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6039</pre>
6040
6041<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6042<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6043 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6044
6045<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6046<p>The only argument is the value to be counted. The argument may be of any
6047 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6048
6049<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6050<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]6051
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6052</div>
6053
6054<!-- _______________________________________________________________________ -->
6055<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6056 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6057</div>
6058
6059<div class="doc_text">
6060
6061<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6062<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6063 integer bit width. Not all targets support all bit widths however.</p>
6064
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6065<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6066 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6067 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6068 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6069 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6070 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6071</pre>
6072
6073<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6074<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6075 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6076
6077<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6078<p>The only argument is the value to be counted. The argument may be of any
6079 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6080
6081<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6082<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6083 zeros in a variable. If the src == 0 then the result is the size in bits of
6084 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6085
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6086</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6087
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6088<!-- _______________________________________________________________________ -->
6089<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6090 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6091</div>
6092
6093<div class="doc_text">
6094
6095<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6096<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6097 integer bit width. Not all targets support all bit widths however.</p>
6098
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6099<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6100 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6101 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6102 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6103 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6104 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6105</pre>
6106
6107<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6108<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6109 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6110
6111<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6112<p>The only argument is the value to be counted. The argument may be of any
6113 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6114
6115<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6116<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6117 zeros in a variable. If the src == 0 then the result is the size in bits of
6118 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6119
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6120</div>
6121
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6122<!-- ======================================================================= -->
6123<div class="doc_subsection">
6124 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6125</div>
6126
6127<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6128
6129<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6130
6131</div>
6132
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6133<!-- _______________________________________________________________________ -->
6134<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6135 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6136</div>
6137
6138<div class="doc_text">
6139
6140<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6141<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]6142 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6143
6144<pre>
6145 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6146 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6147 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6148</pre>
6149
6150<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6151<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6152 a signed addition of the two arguments, and indicate whether an overflow
6153 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6154
6155<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6156<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]6157 be of integer types of any bit width, but they must have the same bit
6158 width. The second element of the result structure must be of
6159 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6160 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6161
6162<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6163<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6164 a signed addition of the two variables. They return a structure &mdash; the
6165 first element of which is the signed summation, and the second element of
6166 which is a bit specifying if the signed summation resulted in an
6167 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6168
6169<h5>Examples:</h5>
6170<pre>
6171 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6172 %sum = extractvalue {i32, i1} %res, 0
6173 %obit = extractvalue {i32, i1} %res, 1
6174 br i1 %obit, label %overflow, label %normal
6175</pre>
6176
6177</div>
6178
6179<!-- _______________________________________________________________________ -->
6180<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6181 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6182</div>
6183
6184<div class="doc_text">
6185
6186<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6187<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]6188 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6189
6190<pre>
6191 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6192 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6193 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6194</pre>
6195
6196<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6197<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6198 an unsigned addition of the two arguments, and indicate whether a carry
6199 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6200
6201<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6202<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]6203 be of integer types of any bit width, but they must have the same bit
6204 width. The second element of the result structure must be of
6205 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6206 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6207
6208<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6209<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6210 an unsigned addition of the two arguments. They return a structure &mdash;
6211 the first element of which is the sum, and the second element of which is a
6212 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6213
6214<h5>Examples:</h5>
6215<pre>
6216 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6217 %sum = extractvalue {i32, i1} %res, 0
6218 %obit = extractvalue {i32, i1} %res, 1
6219 br i1 %obit, label %carry, label %normal
6220</pre>
6221
6222</div>
6223
6224<!-- _______________________________________________________________________ -->
6225<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6226 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6227</div>
6228
6229<div class="doc_text">
6230
6231<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6232<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]6233 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6234
6235<pre>
6236 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6237 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6238 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6239</pre>
6240
6241<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6242<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6243 a signed subtraction of the two arguments, and indicate whether an overflow
6244 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6245
6246<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6247<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]6248 be of integer types of any bit width, but they must have the same bit
6249 width. The second element of the result structure must be of
6250 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6251 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6252
6253<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6254<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6255 a signed subtraction of the two arguments. They return a structure &mdash;
6256 the first element of which is the subtraction, and the second element of
6257 which is a bit specifying if the signed subtraction resulted in an
6258 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6259
6260<h5>Examples:</h5>
6261<pre>
6262 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6263 %sum = extractvalue {i32, i1} %res, 0
6264 %obit = extractvalue {i32, i1} %res, 1
6265 br i1 %obit, label %overflow, label %normal
6266</pre>
6267
6268</div>
6269
6270<!-- _______________________________________________________________________ -->
6271<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6272 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6273</div>
6274
6275<div class="doc_text">
6276
6277<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6278<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]6279 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6280
6281<pre>
6282 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6283 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6284 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6285</pre>
6286
6287<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6288<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6289 an unsigned subtraction of the two arguments, and indicate whether an
6290 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6291
6292<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6293<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]6294 be of integer types of any bit width, but they must have the same bit
6295 width. The second element of the result structure must be of
6296 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6297 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6298
6299<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6300<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6301 an unsigned subtraction of the two arguments. They return a structure &mdash;
6302 the first element of which is the subtraction, and the second element of
6303 which is a bit specifying if the unsigned subtraction resulted in an
6304 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6305
6306<h5>Examples:</h5>
6307<pre>
6308 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6309 %sum = extractvalue {i32, i1} %res, 0
6310 %obit = extractvalue {i32, i1} %res, 1
6311 br i1 %obit, label %overflow, label %normal
6312</pre>
6313
6314</div>
6315
6316<!-- _______________________________________________________________________ -->
6317<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6318 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6319</div>
6320
6321<div class="doc_text">
6322
6323<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6324<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]6325 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6326
6327<pre>
6328 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6329 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6330 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6331</pre>
6332
6333<h5>Overview:</h5>
6334
6335<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6336 a signed multiplication of the two arguments, and indicate whether an
6337 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6338
6339<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6340<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]6341 be of integer types of any bit width, but they must have the same bit
6342 width. The second element of the result structure must be of
6343 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6344 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6345
6346<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6347<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6348 a signed multiplication of the two arguments. They return a structure &mdash;
6349 the first element of which is the multiplication, and the second element of
6350 which is a bit specifying if the signed multiplication resulted in an
6351 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6352
6353<h5>Examples:</h5>
6354<pre>
6355 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6356 %sum = extractvalue {i32, i1} %res, 0
6357 %obit = extractvalue {i32, i1} %res, 1
6358 br i1 %obit, label %overflow, label %normal
6359</pre>
6360
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6361</div>
6362
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6363<!-- _______________________________________________________________________ -->
6364<div class="doc_subsubsection">
6365 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6366</div>
6367
6368<div class="doc_text">
6369
6370<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6371<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]6372 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6373
6374<pre>
6375 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6376 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6377 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6378</pre>
6379
6380<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6381<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6382 a unsigned multiplication of the two arguments, and indicate whether an
6383 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6384
6385<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6386<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]6387 be of integer types of any bit width, but they must have the same bit
6388 width. The second element of the result structure must be of
6389 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6390 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6391
6392<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6393<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6394 an unsigned multiplication of the two arguments. They return a structure
6395 &mdash; the first element of which is the multiplication, and the second
6396 element of which is a bit specifying if the unsigned multiplication resulted
6397 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6398
6399<h5>Examples:</h5>
6400<pre>
6401 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6402 %sum = extractvalue {i32, i1} %res, 0
6403 %obit = extractvalue {i32, i1} %res, 1
6404 br i1 %obit, label %overflow, label %normal
6405</pre>
6406
6407</div>
6408
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6409<!-- ======================================================================= -->
6410<div class="doc_subsection">
6411 <a name="int_debugger">Debugger Intrinsics</a>
6412</div>
6413
6414<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6415
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6416<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6417 prefix), are described in
6418 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6419 Level Debugging</a> document.</p>
6420
6421</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6422
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6423<!-- ======================================================================= -->
6424<div class="doc_subsection">
6425 <a name="int_eh">Exception Handling Intrinsics</a>
6426</div>
6427
6428<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6429
6430<p>The LLVM exception handling intrinsics (which all start with
6431 <tt>llvm.eh.</tt> prefix), are described in
6432 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6433 Handling</a> document.</p>
6434
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6435</div>
6436
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6437<!-- ======================================================================= -->
6438<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6439 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6440</div>
6441
6442<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6443
6444<p>This intrinsic makes it possible to excise one parameter, marked with
6445 the <tt>nest</tt> attribute, from a function. The result is a callable
6446 function pointer lacking the nest parameter - the caller does not need to
6447 provide a value for it. Instead, the value to use is stored in advance in a
6448 "trampoline", a block of memory usually allocated on the stack, which also
6449 contains code to splice the nest value into the argument list. This is used
6450 to implement the GCC nested function address extension.</p>
6451
6452<p>For example, if the function is
6453 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6454 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6455 follows:</p>
6456
6457<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6458<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6459 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6460 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6461 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6462 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6463</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6464</div>
6465
6466<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6467 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6468
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6469</div>
6470
6471<!-- _______________________________________________________________________ -->
6472<div class="doc_subsubsection">
6473 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6474</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6475
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6476<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6477
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6478<h5>Syntax:</h5>
6479<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6480 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]6481</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6482
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6483<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6484<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6485 function pointer suitable for executing it.</p>
6486
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6487<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6488<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6489 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6490 sufficiently aligned block of memory; this memory is written to by the
6491 intrinsic. Note that the size and the alignment are target-specific - LLVM
6492 currently provides no portable way of determining them, so a front-end that
6493 generates this intrinsic needs to have some target-specific knowledge.
6494 The <tt>func</tt> argument must hold a function bitcast to
6495 an <tt>i8*</tt>.</p>
6496
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6497<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6498<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6499 dependent code, turning it into a function. A pointer to this function is
6500 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6501 function pointer type</a> before being called. The new function's signature
6502 is the same as that of <tt>func</tt> with any arguments marked with
6503 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6504 is allowed, and it must be of pointer type. Calling the new function is
6505 equivalent to calling <tt>func</tt> with the same argument list, but
6506 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6507 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6508 by <tt>tramp</tt> is modified, then the effect of any later call to the
6509 returned function pointer is undefined.</p>
6510
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6511</div>
6512
6513<!-- ======================================================================= -->
6514<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6515 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6516</div>
6517
6518<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6519
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6520<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6521 hardware constructs for atomic operations and memory synchronization. This
6522 provides an interface to the hardware, not an interface to the programmer. It
6523 is aimed at a low enough level to allow any programming models or APIs
6524 (Application Programming Interfaces) which need atomic behaviors to map
6525 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6526 hardware provides a "universal IR" for source languages, it also provides a
6527 starting point for developing a "universal" atomic operation and
6528 synchronization IR.</p>
6529
6530<p>These do <em>not</em> form an API such as high-level threading libraries,
6531 software transaction memory systems, atomic primitives, and intrinsic
6532 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6533 application libraries. The hardware interface provided by LLVM should allow
6534 a clean implementation of all of these APIs and parallel programming models.
6535 No one model or paradigm should be selected above others unless the hardware
6536 itself ubiquitously does so.</p>
6537
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6538</div>
6539
6540<!-- _______________________________________________________________________ -->
6541<div class="doc_subsubsection">
6542 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6543</div>
6544<div class="doc_text">
6545<h5>Syntax:</h5>
6546<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6547 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]6548</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6549
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6550<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6551<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6552 specific pairs of memory access types.</p>
6553
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6554<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6555<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6556 The first four arguments enables a specific barrier as listed below. The
6557 fith argument specifies that the barrier applies to io or device or uncached
6558 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6559
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6560<ul>
6561 <li><tt>ll</tt>: load-load barrier</li>
6562 <li><tt>ls</tt>: load-store barrier</li>
6563 <li><tt>sl</tt>: store-load barrier</li>
6564 <li><tt>ss</tt>: store-store barrier</li>
6565 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6566</ul>
6567
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6568<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6569<p>This intrinsic causes the system to enforce some ordering constraints upon
6570 the loads and stores of the program. This barrier does not
6571 indicate <em>when</em> any events will occur, it only enforces
6572 an <em>order</em> in which they occur. For any of the specified pairs of load
6573 and store operations (f.ex. load-load, or store-load), all of the first
6574 operations preceding the barrier will complete before any of the second
6575 operations succeeding the barrier begin. Specifically the semantics for each
6576 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6577
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6578<ul>
6579 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6580 after the barrier begins.</li>
6581 <li><tt>ls</tt>: All loads before the barrier must complete before any
6582 store after the barrier begins.</li>
6583 <li><tt>ss</tt>: All stores before the barrier must complete before any
6584 store after the barrier begins.</li>
6585 <li><tt>sl</tt>: All stores before the barrier must complete before any
6586 load after the barrier begins.</li>
6587</ul>
6588
6589<p>These semantics are applied with a logical "and" behavior when more than one
6590 is enabled in a single memory barrier intrinsic.</p>
6591
6592<p>Backends may implement stronger barriers than those requested when they do
6593 not support as fine grained a barrier as requested. Some architectures do
6594 not need all types of barriers and on such architectures, these become
6595 noops.</p>
6596
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6597<h5>Example:</h5>
6598<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6599%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6600%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6601 store i32 4, %ptr
6602
6603%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6604 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6605 <i>; guarantee the above finishes</i>
6606 store i32 8, %ptr <i>; before this begins</i>
6607</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6608
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6609</div>
6610
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6611<!-- _______________________________________________________________________ -->
6612<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6613 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6614</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6615
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6616<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6617
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6618<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6619<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6620 any integer bit width and for different address spaces. Not all targets
6621 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6622
6623<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6624 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6625 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6626 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6627 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]6628</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6629
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6630<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6631<p>This loads a value in memory and compares it to a given value. If they are
6632 equal, it stores a new value into the memory.</p>
6633
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6634<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6635<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6636 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6637 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6638 this integer type. While any bit width integer may be used, targets may only
6639 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6640
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6641<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6642<p>This entire intrinsic must be executed atomically. It first loads the value
6643 in memory pointed to by <tt>ptr</tt> and compares it with the
6644 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6645 memory. The loaded value is yielded in all cases. This provides the
6646 equivalent of an atomic compare-and-swap operation within the SSA
6647 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6648
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6649<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6650<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6651%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6652%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6653 store i32 4, %ptr
6654
6655%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6656%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6657 <i>; yields {i32}:result1 = 4</i>
6658%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6659%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6660
6661%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6662%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6663 <i>; yields {i32}:result2 = 8</i>
6664%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6665
6666%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6667</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6668
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6669</div>
6670
6671<!-- _______________________________________________________________________ -->
6672<div class="doc_subsubsection">
6673 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6674</div>
6675<div class="doc_text">
6676<h5>Syntax:</h5>
6677
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6678<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6679 integer bit width. Not all targets support all bit widths however.</p>
6680
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6681<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6682 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6683 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6684 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6685 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]6686</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6687
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6688<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6689<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6690 the value from memory. It then stores the value in <tt>val</tt> in the memory
6691 at <tt>ptr</tt>.</p>
6692
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6693<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6694<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6695 the <tt>val</tt> argument and the result must be integers of the same bit
6696 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6697 integer type. The targets may only lower integer representations they
6698 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6699
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6700<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6701<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6702 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6703 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6704
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6705<h5>Examples:</h5>
6706<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6707%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6708%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6709 store i32 4, %ptr
6710
6711%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6712%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6713 <i>; yields {i32}:result1 = 4</i>
6714%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6715%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6716
6717%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6718%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6719 <i>; yields {i32}:result2 = 8</i>
6720
6721%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6722%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6723</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6724
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6725</div>
6726
6727<!-- _______________________________________________________________________ -->
6728<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6729 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6730
6731</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6732
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6733<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6734
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6735<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6736<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6737 any integer bit width. Not all targets support all bit widths however.</p>
6738
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6739<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6740 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6741 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6742 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6743 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]6744</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6745
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6746<h5>Overview:</h5>
6747<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6748 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6749
6750<h5>Arguments:</h5>
6751<p>The intrinsic takes two arguments, the first a pointer to an integer value
6752 and the second an integer value. The result is also an integer value. These
6753 integer types can have any bit width, but they must all have the same bit
6754 width. The targets may only lower integer representations they support.</p>
6755
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6756<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6757<p>This intrinsic does a series of operations atomically. It first loads the
6758 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6759 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]6760
6761<h5>Examples:</h5>
6762<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6763%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6764%ptr = bitcast i8* %mallocP to i32*
6765 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6766%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6767 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6768%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6769 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6770%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6771 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6772%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6773</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6774
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6775</div>
6776
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6777<!-- _______________________________________________________________________ -->
6778<div class="doc_subsubsection">
6779 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6780
6781</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6782
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6783<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6784
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6785<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6786<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6787 any integer bit width and for different address spaces. Not all targets
6788 support all bit widths however.</p>
6789
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6790<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6791 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6792 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6793 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6794 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]6795</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6796
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6797<h5>Overview:</h5>
6798<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6799 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6800
6801<h5>Arguments:</h5>
6802<p>The intrinsic takes two arguments, the first a pointer to an integer value
6803 and the second an integer value. The result is also an integer value. These
6804 integer types can have any bit width, but they must all have the same bit
6805 width. The targets may only lower integer representations they support.</p>
6806
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6807<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6808<p>This intrinsic does a series of operations atomically. It first loads the
6809 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6810 result to <tt>ptr</tt>. It yields the original value stored
6811 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6812
6813<h5>Examples:</h5>
6814<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6815%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6816%ptr = bitcast i8* %mallocP to i32*
6817 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6818%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6819 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6820%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6821 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6822%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6823 <i>; yields {i32}:result3 = 2</i>
6824%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6825</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6826
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6827</div>
6828
6829<!-- _______________________________________________________________________ -->
6830<div class="doc_subsubsection">
6831 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6832 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6833 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6834 <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]6835</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6836
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6837<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6838
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6839<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6840<p>These are overloaded intrinsics. You can
6841 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6842 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6843 bit width and for different address spaces. Not all targets support all bit
6844 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6845
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6846<pre>
6847 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6848 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6849 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6850 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]6851</pre>
6852
6853<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6854 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6855 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6856 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6857 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]6858</pre>
6859
6860<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6861 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6862 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6863 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6864 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]6865</pre>
6866
6867<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6868 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6869 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6870 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6871 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]6872</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6873
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6874<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6875<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6876 the value stored in memory at <tt>ptr</tt>. It yields the original value
6877 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6878
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6879<h5>Arguments:</h5>
6880<p>These intrinsics take two arguments, the first a pointer to an integer value
6881 and the second an integer value. The result is also an integer value. These
6882 integer types can have any bit width, but they must all have the same bit
6883 width. The targets may only lower integer representations they support.</p>
6884
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6885<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6886<p>These intrinsics does a series of operations atomically. They first load the
6887 value stored at <tt>ptr</tt>. They then do the bitwise
6888 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6889 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6890
6891<h5>Examples:</h5>
6892<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6893%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6894%ptr = bitcast i8* %mallocP to i32*
6895 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6896%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6897 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6898%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6899 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6900%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6901 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6902%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6903 <i>; yields {i32}:result3 = FF</i>
6904%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6905</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6906
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6907</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6908
6909<!-- _______________________________________________________________________ -->
6910<div class="doc_subsubsection">
6911 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6912 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6913 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6914 <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]6915</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6916
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6917<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6918
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6919<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6920<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6921 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6922 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6923 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6924
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6925<pre>
6926 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6927 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6928 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6929 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]6930</pre>
6931
6932<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6933 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6934 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6935 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6936 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]6937</pre>
6938
6939<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6940 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6941 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6942 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6943 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]6944</pre>
6945
6946<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6947 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6948 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6949 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6950 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]6951</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6952
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6953<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6954<p>These intrinsics takes the signed or unsigned minimum or maximum of
6955 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6956 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6957
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6958<h5>Arguments:</h5>
6959<p>These intrinsics take two arguments, the first a pointer to an integer value
6960 and the second an integer value. The result is also an integer value. These
6961 integer types can have any bit width, but they must all have the same bit
6962 width. The targets may only lower integer representations they support.</p>
6963
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6964<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6965<p>These intrinsics does a series of operations atomically. They first load the
6966 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6967 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6968 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6969
6970<h5>Examples:</h5>
6971<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6972%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6973%ptr = bitcast i8* %mallocP to i32*
6974 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6975%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6976 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6977%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6978 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6979%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6980 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6981%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6982 <i>; yields {i32}:result3 = 8</i>
6983%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6984</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6985
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6986</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6987
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]6988
6989<!-- ======================================================================= -->
6990<div class="doc_subsection">
6991 <a name="int_memorymarkers">Memory Use Markers</a>
6992</div>
6993
6994<div class="doc_text">
6995
6996<p>This class of intrinsics exists to information about the lifetime of memory
6997 objects and ranges where variables are immutable.</p>
6998
6999</div>
7000
7001<!-- _______________________________________________________________________ -->
7002<div class="doc_subsubsection">
7003 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7004</div>
7005
7006<div class="doc_text">
7007
7008<h5>Syntax:</h5>
7009<pre>
7010 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7011</pre>
7012
7013<h5>Overview:</h5>
7014<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7015 object's lifetime.</p>
7016
7017<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7018<p>The first argument is a constant integer representing the size of the
7019 object, or -1 if it is variable sized. The second argument is a pointer to
7020 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7021
7022<h5>Semantics:</h5>
7023<p>This intrinsic indicates that before this point in the code, the value of the
7024 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]7025 never be used and has an undefined value. A load from the pointer that
7026 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7027 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7028
7029</div>
7030
7031<!-- _______________________________________________________________________ -->
7032<div class="doc_subsubsection">
7033 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7034</div>
7035
7036<div class="doc_text">
7037
7038<h5>Syntax:</h5>
7039<pre>
7040 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7041</pre>
7042
7043<h5>Overview:</h5>
7044<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7045 object's lifetime.</p>
7046
7047<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7048<p>The first argument is a constant integer representing the size of the
7049 object, or -1 if it is variable sized. The second argument is a pointer to
7050 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7051
7052<h5>Semantics:</h5>
7053<p>This intrinsic indicates that after this point in the code, the value of the
7054 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7055 never be used and has an undefined value. Any stores into the memory object
7056 following this intrinsic may be removed as dead.
7057
7058</div>
7059
7060<!-- _______________________________________________________________________ -->
7061<div class="doc_subsubsection">
7062 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7063</div>
7064
7065<div class="doc_text">
7066
7067<h5>Syntax:</h5>
7068<pre>
7069 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7070</pre>
7071
7072<h5>Overview:</h5>
7073<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7074 a memory object will not change.</p>
7075
7076<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7077<p>The first argument is a constant integer representing the size of the
7078 object, or -1 if it is variable sized. The second argument is a pointer to
7079 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7080
7081<h5>Semantics:</h5>
7082<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7083 the return value, the referenced memory location is constant and
7084 unchanging.</p>
7085
7086</div>
7087
7088<!-- _______________________________________________________________________ -->
7089<div class="doc_subsubsection">
7090 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7091</div>
7092
7093<div class="doc_text">
7094
7095<h5>Syntax:</h5>
7096<pre>
7097 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7098</pre>
7099
7100<h5>Overview:</h5>
7101<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7102 a memory object are mutable.</p>
7103
7104<h5>Arguments:</h5>
7105<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7106 The second argument is a constant integer representing the size of the
7107 object, or -1 if it is variable sized and the third argument is a pointer
7108 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7109
7110<h5>Semantics:</h5>
7111<p>This intrinsic indicates that the memory is mutable again.</p>
7112
7113</div>
7114
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7115<!-- ======================================================================= -->
7116<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7117 <a name="int_general">General Intrinsics</a>
7118</div>
7119
7120<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7121
7122<p>This class of intrinsics is designed to be generic and has no specific
7123 purpose.</p>
7124
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7125</div>
7126
7127<!-- _______________________________________________________________________ -->
7128<div class="doc_subsubsection">
7129 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7130</div>
7131
7132<div class="doc_text">
7133
7134<h5>Syntax:</h5>
7135<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7136 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]7137</pre>
7138
7139<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7140<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7141
7142<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7143<p>The first argument is a pointer to a value, the second is a pointer to a
7144 global string, the third is a pointer to a global string which is the source
7145 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7146
7147<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7148<p>This intrinsic allows annotation of local variables with arbitrary strings.
7149 This can be useful for special purpose optimizations that want to look for
7150 these annotations. These have no other defined use, they are ignored by code
7151 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7152
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7153</div>
7154
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7155<!-- _______________________________________________________________________ -->
7156<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7157 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7158</div>
7159
7160<div class="doc_text">
7161
7162<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7163<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7164 any integer bit width.</p>
7165
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7166<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7167 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7168 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7169 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7170 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7171 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]7172</pre>
7173
7174<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7175<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7176
7177<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7178<p>The first argument is an integer value (result of some expression), the
7179 second is a pointer to a global string, the third is a pointer to a global
7180 string which is the source file name, and the last argument is the line
7181 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7182
7183<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7184<p>This intrinsic allows annotations to be put on arbitrary expressions with
7185 arbitrary strings. This can be useful for special purpose optimizations that
7186 want to look for these annotations. These have no other defined use, they
7187 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7188
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7189</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7190
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7191<!-- _______________________________________________________________________ -->
7192<div class="doc_subsubsection">
7193 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7194</div>
7195
7196<div class="doc_text">
7197
7198<h5>Syntax:</h5>
7199<pre>
7200 declare void @llvm.trap()
7201</pre>
7202
7203<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7204<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7205
7206<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7207<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7208
7209<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7210<p>This intrinsics is lowered to the target dependent trap instruction. If the
7211 target does not have a trap instruction, this intrinsic will be lowered to
7212 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7213
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7214</div>
7215
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7216<!-- _______________________________________________________________________ -->
7217<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7218 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7219</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7220
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7221<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7222
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7223<h5>Syntax:</h5>
7224<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7225 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7226</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7227
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7228<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7229<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7230 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7231 ensure that it is placed on the stack before local variables.</p>
7232
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7233<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7234<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7235 arguments. The first argument is the value loaded from the stack
7236 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7237 that has enough space to hold the value of the guard.</p>
7238
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7239<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7240<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7241 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7242 stack. This is to ensure that if a local variable on the stack is
7243 overwritten, it will destroy the value of the guard. When the function exits,
7244 the guard on the stack is checked against the original guard. If they're
7245 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7246 function.</p>
7247
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7248</div>
7249
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7250<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7251<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7252<address>
7253 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7254 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7255 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7256 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]7257
7258 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7259 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7260 Last modified: $Date$
7261</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7262
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7263</body>
7264</html>