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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 21c346e1714c50b2567de9e1d1a9184783fe5c0a / . / 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>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1218</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1219
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1220<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1221 default set of specifications which are then (possibly) overriden by the
1222 specifications in the <tt>datalayout</tt> keyword. The default specifications
1223 are given in this list:</p>
1224
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1225<ul>
1226 <li><tt>E</tt> - big endian</li>
1227 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1228 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1229 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1230 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1231 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1232 <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]1233 alignment of 64-bits</li>
1234 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1235 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1236 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1237 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1238 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1239 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1240</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1241
1242<p>When LLVM is determining the alignment for a given type, it uses the
1243 following rules:</p>
1244
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1245<ol>
1246 <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]1247 specification is used.</li>
1248
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1249 <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]1250 smallest integer type that is larger than the bitwidth of the sought type
1251 is used. If none of the specifications are larger than the bitwidth then
1252 the the largest integer type is used. For example, given the default
1253 specifications above, the i7 type will use the alignment of i8 (next
1254 largest) while both i65 and i256 will use the alignment of i64 (largest
1255 specified).</li>
1256
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1257 <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]1258 largest vector type that is smaller than the sought vector type will be
1259 used as a fall back. This happens because &lt;128 x double&gt; can be
1260 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1261</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1262
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1263</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1264
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1265<!-- ======================================================================= -->
1266<div class="doc_subsection">
1267 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1268</div>
1269
1270<div class="doc_text">
1271
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1272<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1273with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1274is undefined. Pointer values are associated with address ranges
1275according to the following rules:</p>
1276
1277<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1278 <li>A pointer value formed from a
1279 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1280 is associated with the addresses associated with the first operand
1281 of the <tt>getelementptr</tt>.</li>
1282 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1283 range of the variable's storage.</li>
1284 <li>The result value of an allocation instruction is associated with
1285 the address range of the allocated storage.</li>
1286 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1287 no address.</li>
1288 <li>A pointer value formed by an
1289 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1290 address ranges of all pointer values that contribute (directly or
1291 indirectly) to the computation of the pointer's value.</li>
1292 <li>The result value of a
1293 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1294 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1295 <li>An integer constant other than zero or a pointer value returned
1296 from a function not defined within LLVM may be associated with address
1297 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1298 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1299 allocated by mechanisms provided by LLVM.</li>
1300 </ul>
1301
1302<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1303<tt><a href="#i_load">load</a></tt> merely indicates the size and
1304alignment of the memory from which to load, as well as the
1305interpretation of the value. The first operand of a
1306<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1307and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1308
1309<p>Consequently, type-based alias analysis, aka TBAA, aka
1310<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1311LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1312additional information which specialized optimization passes may use
1313to implement type-based alias analysis.</p>
1314
1315</div>
1316
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1317<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1318<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1319<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1320
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1321<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1322
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1323<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1324 intermediate representation. Being typed enables a number of optimizations
1325 to be performed on the intermediate representation directly, without having
1326 to do extra analyses on the side before the transformation. A strong type
1327 system makes it easier to read the generated code and enables novel analyses
1328 and transformations that are not feasible to perform on normal three address
1329 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1330
1331</div>
1332
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1333<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1334<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1335Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1336
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1337<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1338
1339<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1340
1341<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1342 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1343 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1344 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1345 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1346 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1347 </tr>
1348 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1349 <td><a href="#t_floating">floating point</a></td>
1350 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1351 </tr>
1352 <tr>
1353 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1354 <td><a href="#t_integer">integer</a>,
1355 <a href="#t_floating">floating point</a>,
1356 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1357 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1358 <a href="#t_struct">structure</a>,
1359 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1360 <a href="#t_label">label</a>,
1361 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1362 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1363 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1364 <tr>
1365 <td><a href="#t_primitive">primitive</a></td>
1366 <td><a href="#t_label">label</a>,
1367 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1368 <a href="#t_floating">floating point</a>,
1369 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1370 </tr>
1371 <tr>
1372 <td><a href="#t_derived">derived</a></td>
1373 <td><a href="#t_integer">integer</a>,
1374 <a href="#t_array">array</a>,
1375 <a href="#t_function">function</a>,
1376 <a href="#t_pointer">pointer</a>,
1377 <a href="#t_struct">structure</a>,
1378 <a href="#t_pstruct">packed structure</a>,
1379 <a href="#t_vector">vector</a>,
1380 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1381 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1382 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1383 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1384</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1385
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1386<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1387 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1388 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1389
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1390</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1391
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1392<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1393<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1394
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1395<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1396
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1397<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1398 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1399
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1400</div>
1401
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1402<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1403<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1404
1405<div class="doc_text">
1406
1407<h5>Overview:</h5>
1408<p>The integer type is a very simple type that simply specifies an arbitrary
1409 bit width for the integer type desired. Any bit width from 1 bit to
1410 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1411
1412<h5>Syntax:</h5>
1413<pre>
1414 iN
1415</pre>
1416
1417<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1418 value.</p>
1419
1420<h5>Examples:</h5>
1421<table class="layout">
1422 <tr class="layout">
1423 <td class="left"><tt>i1</tt></td>
1424 <td class="left">a single-bit integer.</td>
1425 </tr>
1426 <tr class="layout">
1427 <td class="left"><tt>i32</tt></td>
1428 <td class="left">a 32-bit integer.</td>
1429 </tr>
1430 <tr class="layout">
1431 <td class="left"><tt>i1942652</tt></td>
1432 <td class="left">a really big integer of over 1 million bits.</td>
1433 </tr>
1434</table>
1435
1436<p>Note that the code generator does not yet support large integer types to be
1437 used as function return types. The specific limit on how large a return type
1438 the code generator can currently handle is target-dependent; currently it's
1439 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
1440
1441</div>
1442
1443<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1444<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1445
1446<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1447
1448<table>
1449 <tbody>
1450 <tr><th>Type</th><th>Description</th></tr>
1451 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1452 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1453 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1454 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1455 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1456 </tbody>
1457</table>
1458
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1459</div>
1460
1461<!-- _______________________________________________________________________ -->
1462<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1463
1464<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1465
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1466<h5>Overview:</h5>
1467<p>The void type does not represent any value and has no size.</p>
1468
1469<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1470<pre>
1471 void
1472</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1473
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1474</div>
1475
1476<!-- _______________________________________________________________________ -->
1477<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1478
1479<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1480
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1481<h5>Overview:</h5>
1482<p>The label type represents code labels.</p>
1483
1484<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1485<pre>
1486 label
1487</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1488
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1489</div>
1490
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1491<!-- _______________________________________________________________________ -->
1492<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1493
1494<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1495
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1496<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1497<p>The metadata type represents embedded metadata. No derived types may be
1498 created from metadata except for <a href="#t_function">function</a>
1499 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1500
1501<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1502<pre>
1503 metadata
1504</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1505
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1506</div>
1507
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1508
1509<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1510<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1511
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1512<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1513
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1514<p>The real power in LLVM comes from the derived types in the system. This is
1515 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1516 useful types. Each of these types contain one or more element types which
1517 may be a primitive type, or another derived type. For example, it is
1518 possible to have a two dimensional array, using an array as the element type
1519 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1520
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1521</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1522
1523<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1524<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1525
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1526<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1527
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1528<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1529<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1530 sequentially in memory. The array type requires a size (number of elements)
1531 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1532
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1533<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1534<pre>
1535 [&lt;# elements&gt; x &lt;elementtype&gt;]
1536</pre>
1537
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1538<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1539 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1540
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1541<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1542<table class="layout">
1543 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1544 <td class="left"><tt>[40 x i32]</tt></td>
1545 <td class="left">Array of 40 32-bit integer values.</td>
1546 </tr>
1547 <tr class="layout">
1548 <td class="left"><tt>[41 x i32]</tt></td>
1549 <td class="left">Array of 41 32-bit integer values.</td>
1550 </tr>
1551 <tr class="layout">
1552 <td class="left"><tt>[4 x i8]</tt></td>
1553 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1554 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1555</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1556<p>Here are some examples of multidimensional arrays:</p>
1557<table class="layout">
1558 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1559 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1560 <td class="left">3x4 array of 32-bit integer values.</td>
1561 </tr>
1562 <tr class="layout">
1563 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1564 <td class="left">12x10 array of single precision floating point values.</td>
1565 </tr>
1566 <tr class="layout">
1567 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1568 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1569 </tr>
1570</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1571
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1572<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1573 length array. Normally, accesses past the end of an array are undefined in
1574 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1575 a special case, however, zero length arrays are recognized to be variable
1576 length. This allows implementation of 'pascal style arrays' with the LLVM
1577 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1578
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1579<p>Note that the code generator does not yet support large aggregate types to be
1580 used as function return types. The specific limit on how large an aggregate
1581 return type the code generator can currently handle is target-dependent, and
1582 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1583
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1584</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1585
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1586<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1587<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1588
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1589<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1590
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1591<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1592<p>The function type can be thought of as a function signature. It consists of
1593 a return type and a list of formal parameter types. The return type of a
1594 function type is a scalar type, a void type, or a struct type. If the return
1595 type is a struct type then all struct elements must be of first class types,
1596 and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1597
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1598<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1599<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1600 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1601</pre>
1602
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1603<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]1604 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1605 which indicates that the function takes a variable number of arguments.
1606 Variable argument functions can access their arguments with
1607 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1608 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1609 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1610
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1611<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1612<table class="layout">
1613 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1614 <td class="left"><tt>i32 (i32)</tt></td>
1615 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1616 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1617 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1618 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1619 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1620 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1621 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1622 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1623 <tt>float</tt>.
1624 </td>
1625 </tr><tr class="layout">
1626 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1627 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1628 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1629 which returns an integer. This is the signature for <tt>printf</tt> in
1630 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1631 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1632 </tr><tr class="layout">
1633 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1634 <td class="left">A function taking an <tt>i32</tt>, returning a
1635 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1636 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1637 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1638</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1639
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1640</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1641
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1642<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1643<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1644
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1645<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1646
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1647<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1648<p>The structure type is used to represent a collection of data members together
1649 in memory. The packing of the field types is defined to match the ABI of the
1650 underlying processor. The elements of a structure may be any type that has a
1651 size.</p>
1652
1653<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1654 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1655 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1656
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1657<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1658<pre>
1659 { &lt;type list&gt; }
1660</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1661
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1662<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1663<table class="layout">
1664 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1665 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1666 <td class="left">A triple of three <tt>i32</tt> values</td>
1667 </tr><tr class="layout">
1668 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1669 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1670 second element is a <a href="#t_pointer">pointer</a> to a
1671 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1672 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1673 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1674</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1675
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1676<p>Note that the code generator does not yet support large aggregate types to be
1677 used as function return types. The specific limit on how large an aggregate
1678 return type the code generator can currently handle is target-dependent, and
1679 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1680
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1681</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1682
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1683<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1684<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1685</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1686
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1687<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1688
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1689<h5>Overview:</h5>
1690<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1691 together in memory. There is no padding between fields. Further, the
1692 alignment of a packed structure is 1 byte. The elements of a packed
1693 structure may be any type that has a size.</p>
1694
1695<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1696 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1697 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1698
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1699<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1700<pre>
1701 &lt; { &lt;type list&gt; } &gt;
1702</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1703
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1704<h5>Examples:</h5>
1705<table class="layout">
1706 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1707 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1708 <td class="left">A triple of three <tt>i32</tt> values</td>
1709 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1710 <td class="left">
1711<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1712 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1713 second element is a <a href="#t_pointer">pointer</a> to a
1714 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1715 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1716 </tr>
1717</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1718
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1719</div>
1720
1721<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1722<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1723
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1724<div class="doc_text">
1725
1726<h5>Overview:</h5>
1727<p>As in many languages, the pointer type represents a pointer or reference to
1728 another object, which must live in memory. Pointer types may have an optional
1729 address space attribute defining the target-specific numbered address space
1730 where the pointed-to object resides. The default address space is zero.</p>
1731
1732<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1733 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1734
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1735<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1736<pre>
1737 &lt;type&gt; *
1738</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1739
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1740<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1741<table class="layout">
1742 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1743 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1744 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1745 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1746 </tr>
1747 <tr class="layout">
1748 <td class="left"><tt>i32 (i32 *) *</tt></td>
1749 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1750 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1751 <tt>i32</tt>.</td>
1752 </tr>
1753 <tr class="layout">
1754 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1755 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1756 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1757 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1758</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1759
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1760</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1761
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1762<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1763<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1764
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1765<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1766
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1767<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1768<p>A vector type is a simple derived type that represents a vector of elements.
1769 Vector types are used when multiple primitive data are operated in parallel
1770 using a single instruction (SIMD). A vector type requires a size (number of
1771 elements) and an underlying primitive data type. Vectors must have a power
1772 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1773 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1774
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1775<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1776<pre>
1777 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1778</pre>
1779
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1780<p>The number of elements is a constant integer value; elementtype may be any
1781 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1782
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1783<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1784<table class="layout">
1785 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1786 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1787 <td class="left">Vector of 4 32-bit integer values.</td>
1788 </tr>
1789 <tr class="layout">
1790 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1791 <td class="left">Vector of 8 32-bit floating-point values.</td>
1792 </tr>
1793 <tr class="layout">
1794 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1795 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1796 </tr>
1797</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1798
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1799<p>Note that the code generator does not yet support large vector types to be
1800 used as function return types. The specific limit on how large a vector
1801 return type codegen can currently handle is target-dependent; currently it's
1802 often a few times longer than a hardware vector register.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1803
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1804</div>
1805
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1806<!-- _______________________________________________________________________ -->
1807<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1808<div class="doc_text">
1809
1810<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1811<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1812 corresponds (for example) to the C notion of a forward declared structure
1813 type. In LLVM, opaque types can eventually be resolved to any type (not just
1814 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1815
1816<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1817<pre>
1818 opaque
1819</pre>
1820
1821<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1822<table class="layout">
1823 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1824 <td class="left"><tt>opaque</tt></td>
1825 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1826 </tr>
1827</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1828
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1829</div>
1830
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1831<!-- ======================================================================= -->
1832<div class="doc_subsection">
1833 <a name="t_uprefs">Type Up-references</a>
1834</div>
1835
1836<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1837
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1838<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1839<p>An "up reference" allows you to refer to a lexically enclosing type without
1840 requiring it to have a name. For instance, a structure declaration may
1841 contain a pointer to any of the types it is lexically a member of. Example
1842 of up references (with their equivalent as named type declarations)
1843 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1844
1845<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1846 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1847 { \2 }* %y = type { %y }*
1848 \1* %z = type %z*
1849</pre>
1850
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1851<p>An up reference is needed by the asmprinter for printing out cyclic types
1852 when there is no declared name for a type in the cycle. Because the
1853 asmprinter does not want to print out an infinite type string, it needs a
1854 syntax to handle recursive types that have no names (all names are optional
1855 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1856
1857<h5>Syntax:</h5>
1858<pre>
1859 \&lt;level&gt;
1860</pre>
1861
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1862<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]1863
1864<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1865<table class="layout">
1866 <tr class="layout">
1867 <td class="left"><tt>\1*</tt></td>
1868 <td class="left">Self-referential pointer.</td>
1869 </tr>
1870 <tr class="layout">
1871 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1872 <td class="left">Recursive structure where the upref refers to the out-most
1873 structure.</td>
1874 </tr>
1875</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1876
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1877</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1878
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1879<!-- *********************************************************************** -->
1880<div class="doc_section"> <a name="constants">Constants</a> </div>
1881<!-- *********************************************************************** -->
1882
1883<div class="doc_text">
1884
1885<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1886 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1887
1888</div>
1889
1890<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1891<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1892
1893<div class="doc_text">
1894
1895<dl>
1896 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1897 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1898 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1899
1900 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1901 <dd>Standard integers (such as '4') are constants of
1902 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1903 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1904
1905 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1906 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1907 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1908 notation (see below). The assembler requires the exact decimal value of a
1909 floating-point constant. For example, the assembler accepts 1.25 but
1910 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1911 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1912
1913 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1914 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1915 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1916</dl>
1917
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1918<p>The one non-intuitive notation for constants is the hexadecimal form of
1919 floating point constants. For example, the form '<tt>double
1920 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1921 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1922 constants are required (and the only time that they are generated by the
1923 disassembler) is when a floating point constant must be emitted but it cannot
1924 be represented as a decimal floating point number in a reasonable number of
1925 digits. For example, NaN's, infinities, and other special values are
1926 represented in their IEEE hexadecimal format so that assembly and disassembly
1927 do not cause any bits to change in the constants.</p>
1928
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]1929<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1930 represented using the 16-digit form shown above (which matches the IEEE754
1931 representation for double); float values must, however, be exactly
1932 representable as IEE754 single precision. Hexadecimal format is always used
1933 for long double, and there are three forms of long double. The 80-bit format
1934 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1935 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1936 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1937 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1938 currently supported target uses this format. Long doubles will only work if
1939 they match the long double format on your target. All hexadecimal formats
1940 are big-endian (sign bit at the left).</p>
1941
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1942</div>
1943
1944<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1945<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]1946<a name="aggregateconstants"></a> <!-- old anchor -->
1947<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1948</div>
1949
1950<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1951
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1952<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1953 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1954
1955<dl>
1956 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1957 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1958 type definitions (a comma separated list of elements, surrounded by braces
1959 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1960 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1961 Structure constants must have <a href="#t_struct">structure type</a>, and
1962 the number and types of elements must match those specified by the
1963 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1964
1965 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1966 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1967 definitions (a comma separated list of elements, surrounded by square
1968 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1969 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1970 the number and types of elements must match those specified by the
1971 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1972
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1973 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1974 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1975 definitions (a comma separated list of elements, surrounded by
1976 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1977 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1978 have <a href="#t_vector">vector type</a>, and the number and types of
1979 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1980
1981 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1982 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1983 value to zero of <em>any</em> type, including scalar and aggregate types.
1984 This is often used to avoid having to print large zero initializers
1985 (e.g. for large arrays) and is always exactly equivalent to using explicit
1986 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]1987
1988 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]1989 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1990 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1991 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1992 be interpreted as part of the instruction stream, metadata is a place to
1993 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1994</dl>
1995
1996</div>
1997
1998<!-- ======================================================================= -->
1999<div class="doc_subsection">
2000 <a name="globalconstants">Global Variable and Function Addresses</a>
2001</div>
2002
2003<div class="doc_text">
2004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2005<p>The addresses of <a href="#globalvars">global variables</a>
2006 and <a href="#functionstructure">functions</a> are always implicitly valid
2007 (link-time) constants. These constants are explicitly referenced when
2008 the <a href="#identifiers">identifier for the global</a> is used and always
2009 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2010 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2011
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2012<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2013<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2014@X = global i32 17
2015@Y = global i32 42
2016@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2017</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2018</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2019
2020</div>
2021
2022<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2023<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2024<div class="doc_text">
2025
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2026<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]2027 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2028 Undefined values may be of any type (other than label or void) and be used
2029 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2030
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2031<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2032 program is well defined no matter what value is used. This gives the
2033 compiler more freedom to optimize. Here are some examples of (potentially
2034 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2035
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2036
2037<div class="doc_code">
2038<pre>
2039 %A = add %X, undef
2040 %B = sub %X, undef
2041 %C = xor %X, undef
2042Safe:
2043 %A = undef
2044 %B = undef
2045 %C = undef
2046</pre>
2047</div>
2048
2049<p>This is safe because all of the output bits are affected by the undef bits.
2050Any output bit can have a zero or one depending on the input bits.</p>
2051
2052<div class="doc_code">
2053<pre>
2054 %A = or %X, undef
2055 %B = and %X, undef
2056Safe:
2057 %A = -1
2058 %B = 0
2059Unsafe:
2060 %A = undef
2061 %B = undef
2062</pre>
2063</div>
2064
2065<p>These logical operations have bits that are not always affected by the input.
2066For example, if "%X" has a zero bit, then the output of the 'and' operation will
2067always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2068such, it is unsafe to optimize or assume that the result of the and is undef.
2069However, it is safe to assume that all bits of the undef could be 0, and
2070optimize the and to 0. Likewise, it is safe to assume that all the bits of
2071the undef operand to the or could be set, allowing the or to be folded to
2072-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2073
2074<div class="doc_code">
2075<pre>
2076 %A = select undef, %X, %Y
2077 %B = select undef, 42, %Y
2078 %C = select %X, %Y, undef
2079Safe:
2080 %A = %X (or %Y)
2081 %B = 42 (or %Y)
2082 %C = %Y
2083Unsafe:
2084 %A = undef
2085 %B = undef
2086 %C = undef
2087</pre>
2088</div>
2089
2090<p>This set of examples show that undefined select (and conditional branch)
2091conditions can go "either way" but they have to come from one of the two
2092operands. In the %A example, if %X and %Y were both known to have a clear low
2093bit, then %A would have to have a cleared low bit. However, in the %C example,
2094the optimizer is allowed to assume that the undef operand could be the same as
2095%Y, allowing the whole select to be eliminated.</p>
2096
2097
2098<div class="doc_code">
2099<pre>
2100 %A = xor undef, undef
2101
2102 %B = undef
2103 %C = xor %B, %B
2104
2105 %D = undef
2106 %E = icmp lt %D, 4
2107 %F = icmp gte %D, 4
2108
2109Safe:
2110 %A = undef
2111 %B = undef
2112 %C = undef
2113 %D = undef
2114 %E = undef
2115 %F = undef
2116</pre>
2117</div>
2118
2119<p>This example points out that two undef operands are not necessarily the same.
2120This can be surprising to people (and also matches C semantics) where they
2121assume that "X^X" is always zero, even if X is undef. This isn't true for a
2122number of reasons, but the short answer is that an undef "variable" can
2123arbitrarily change its value over its "live range". This is true because the
2124"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2125logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2126so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2127to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2128would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2129
2130<div class="doc_code">
2131<pre>
2132 %A = fdiv undef, %X
2133 %B = fdiv %X, undef
2134Safe:
2135 %A = undef
2136b: unreachable
2137</pre>
2138</div>
2139
2140<p>These examples show the crucial difference between an <em>undefined
2141value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2142allowed to have an arbitrary bit-pattern. This means that the %A operation
2143can be constant folded to undef because the undef could be an SNaN, and fdiv is
2144not (currently) defined on SNaN's. However, in the second example, we can make
2145a more aggressive assumption: because the undef is allowed to be an arbitrary
2146value, 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]2147has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2148does not execute at all. This allows us to delete the divide and all code after
2149it: since the undefined operation "can't happen", the optimizer can assume that
2150it occurs in dead code.
2151</p>
2152
2153<div class="doc_code">
2154<pre>
2155a: store undef -> %X
2156b: store %X -> undef
2157Safe:
2158a: &lt;deleted&gt;
2159b: unreachable
2160</pre>
2161</div>
2162
2163<p>These examples reiterate the fdiv example: a store "of" an undefined value
2164can be assumed to not have any effect: we can assume that the value is
2165overwritten with bits that happen to match what was already there. However, a
2166store "to" an undefined location could clobber arbitrary memory, therefore, it
2167has undefined behavior.</p>
2168
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2169</div>
2170
2171<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2172<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2173 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2174<div class="doc_text">
2175
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2176<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2177
2178<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2179 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2180 the address of the entry block is illegal.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2181
2182<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2183 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2184 against null. Pointer equality tests between labels addresses is undefined
2185 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2186 equal to the null pointer. This may also be passed around as an opaque
2187 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2188 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2189 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2190
2191<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2192 using the value as the operand to an inline assembly, but that is target
2193 specific.
2194 </p>
2195
2196</div>
2197
2198
2199<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2200<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2201</div>
2202
2203<div class="doc_text">
2204
2205<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2206 to be used as constants. Constant expressions may be of
2207 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2208 operation that does not have side effects (e.g. load and call are not
2209 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2210
2211<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2212 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2213 <dd>Truncate a constant to another type. The bit size of CST must be larger
2214 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2215
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2216 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2217 <dd>Zero extend a constant to another type. The bit size of CST must be
2218 smaller or equal to the bit size of TYPE. Both types must be
2219 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2220
2221 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2222 <dd>Sign extend a constant to another type. The bit size of CST must be
2223 smaller or equal to the bit size of TYPE. Both types must be
2224 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2225
2226 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2227 <dd>Truncate a floating point constant to another floating point type. The
2228 size of CST must be larger than the size of TYPE. Both types must be
2229 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2230
2231 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2232 <dd>Floating point extend a constant to another type. The size of CST must be
2233 smaller or equal to the size of TYPE. Both types must be floating
2234 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2235
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2236 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2237 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2238 constant. TYPE must be a scalar or vector integer type. CST must be of
2239 scalar or vector floating point type. Both CST and TYPE must be scalars,
2240 or vectors of the same number of elements. If the value won't fit in the
2241 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2242
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2243 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2244 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2245 constant. TYPE must be a scalar or vector integer type. CST must be of
2246 scalar or vector floating point type. Both CST and TYPE must be scalars,
2247 or vectors of the same number of elements. If the value won't fit in the
2248 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2249
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2250 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2251 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2252 constant. TYPE must be a scalar or vector floating point type. CST must be
2253 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2254 vectors of the same number of elements. If the value won't fit in the
2255 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2256
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2257 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2258 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2259 constant. TYPE must be a scalar or vector floating point type. CST must be
2260 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2261 vectors of the same number of elements. If the value won't fit in the
2262 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2263
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2264 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2265 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2266 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2267 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2268 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2269
2270 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2271 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2272 type. CST must be of integer type. The CST value is zero extended,
2273 truncated, or unchanged to make it fit in a pointer size. This one is
2274 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2275
2276 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2277 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2278 are the same as those for the <a href="#i_bitcast">bitcast
2279 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2280
2281 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2282 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2283 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2284 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2285 instruction, the index list may have zero or more indexes, which are
2286 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2287
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2288 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2289 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2290
2291 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2292 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2293
2294 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2295 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2296
2297 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2298 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2299 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2300
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2301 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2302 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2303 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2304
2305 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2306 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2307 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2308
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2309 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2310 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2311 be any of the <a href="#binaryops">binary</a>
2312 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2313 on operands are the same as those for the corresponding instruction
2314 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2315</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2316
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2317</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2318
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2319<!-- ======================================================================= -->
2320<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2321</div>
2322
2323<div class="doc_text">
2324
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2325<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2326 stream without affecting the behaviour of the program. There are two
2327 metadata primitives, strings and nodes. All metadata has the
2328 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2329 point ('<tt>!</tt>').</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2330
2331<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2332 any character by escaping non-printable characters with "\xx" where "xx" is
2333 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2334
2335<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2336 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2337 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2338 10}</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2339
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2340<p>A metadata node will attempt to track changes to the values it holds. In the
2341 event that a value is deleted, it will be replaced with a typeless
2342 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckycb337992009-05-10 20:57:05 +0000[diff] [blame]2343
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2344<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2345 the program that isn't available in the instructions, or that isn't easily
2346 computable. Similarly, the code generator may expect a certain metadata
2347 format to be used to express debugging information.</p>
2348
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2349</div>
2350
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2351<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2352<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2353<!-- *********************************************************************** -->
2354
2355<!-- ======================================================================= -->
2356<div class="doc_subsection">
2357<a name="inlineasm">Inline Assembler Expressions</a>
2358</div>
2359
2360<div class="doc_text">
2361
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2362<p>LLVM supports inline assembler expressions (as opposed
2363 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2364 a special value. This value represents the inline assembler as a string
2365 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2366 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2367 expression has side effects, and a flag indicating whether the function
2368 containing the asm needs to align its stack conservatively. An example
2369 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2370
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2371<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2372<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2373i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2374</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2375</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2376
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2377<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2378 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2379 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2380
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2381<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2382<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2383%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]2384</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2385</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2386
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2387<p>Inline asms with side effects not visible in the constraint list must be
2388 marked as having side effects. This is done through the use of the
2389 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2390
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2391<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2392<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2393call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2394</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2395</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2396
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2397<p>In some cases inline asms will contain code that will not work unless the
2398 stack is aligned in some way, such as calls or SSE instructions on x86,
2399 yet will not contain code that does that alignment within the asm.
2400 The compiler should make conservative assumptions about what the asm might
2401 contain and should generate its usual stack alignment code in the prologue
2402 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2403
2404<div class="doc_code">
2405<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2406call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2407</pre>
2408</div>
2409
2410<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2411 first.</p>
2412
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2413<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2414 documented here. Constraints on what can be done (e.g. duplication, moving,
2415 etc need to be documented). This is probably best done by reference to
2416 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2417
2418</div>
2419
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2420
2421<!-- *********************************************************************** -->
2422<div class="doc_section">
2423 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2424</div>
2425<!-- *********************************************************************** -->
2426
2427<p>LLVM has a number of "magic" global variables that contain data that affect
2428code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2429of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2430section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2431by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2432
2433<!-- ======================================================================= -->
2434<div class="doc_subsection">
2435<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2436</div>
2437
2438<div class="doc_text">
2439
2440<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2441href="#linkage_appending">appending linkage</a>. This array contains a list of
2442pointers to global variables and functions which may optionally have a pointer
2443cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2444
2445<pre>
2446 @X = global i8 4
2447 @Y = global i32 123
2448
2449 @llvm.used = appending global [2 x i8*] [
2450 i8* @X,
2451 i8* bitcast (i32* @Y to i8*)
2452 ], section "llvm.metadata"
2453</pre>
2454
2455<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2456compiler, assembler, and linker are required to treat the symbol as if there is
2457a reference to the global that it cannot see. For example, if a variable has
2458internal linkage and no references other than that from the <tt>@llvm.used</tt>
2459list, it cannot be deleted. This is commonly used to represent references from
2460inline asms and other things the compiler cannot "see", and corresponds to
2461"attribute((used))" in GNU C.</p>
2462
2463<p>On some targets, the code generator must emit a directive to the assembler or
2464object file to prevent the assembler and linker from molesting the symbol.</p>
2465
2466</div>
2467
2468<!-- ======================================================================= -->
2469<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2470<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2471</div>
2472
2473<div class="doc_text">
2474
2475<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2476<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2477touching the symbol. On targets that support it, this allows an intelligent
2478linker to optimize references to the symbol without being impeded as it would be
2479by <tt>@llvm.used</tt>.</p>
2480
2481<p>This is a rare construct that should only be used in rare circumstances, and
2482should not be exposed to source languages.</p>
2483
2484</div>
2485
2486<!-- ======================================================================= -->
2487<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2488<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2489</div>
2490
2491<div class="doc_text">
2492
2493<p>TODO: Describe this.</p>
2494
2495</div>
2496
2497<!-- ======================================================================= -->
2498<div class="doc_subsection">
2499<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2500</div>
2501
2502<div class="doc_text">
2503
2504<p>TODO: Describe this.</p>
2505
2506</div>
2507
2508
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2509<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2510<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2511<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2512
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2513<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2514
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2515<p>The LLVM instruction set consists of several different classifications of
2516 instructions: <a href="#terminators">terminator
2517 instructions</a>, <a href="#binaryops">binary instructions</a>,
2518 <a href="#bitwiseops">bitwise binary instructions</a>,
2519 <a href="#memoryops">memory instructions</a>, and
2520 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2521
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2522</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2523
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2524<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2525<div class="doc_subsection"> <a name="terminators">Terminator
2526Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2527
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2528<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2529
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2530<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2531 in a program ends with a "Terminator" instruction, which indicates which
2532 block should be executed after the current block is finished. These
2533 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2534 control flow, not values (the one exception being the
2535 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2536
2537<p>There are six different terminator instructions: the
2538 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2539 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2540 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame^]2541 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2542 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2543 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2544 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2545
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2546</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2547
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2548<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2549<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2550Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2551
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2552<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2553
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2554<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2555<pre>
2556 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]2557 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2558</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2559
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2560<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2561<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2562 a value) from a function back to the caller.</p>
2563
2564<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2565 value and then causes control flow, and one that just causes control flow to
2566 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2567
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2568<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2569<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2570 return value. The type of the return value must be a
2571 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2572
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2573<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2574 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2575 value or a return value with a type that does not match its type, or if it
2576 has a void return type and contains a '<tt>ret</tt>' instruction with a
2577 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2578
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2579<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2580<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2581 the calling function's context. If the caller is a
2582 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2583 instruction after the call. If the caller was an
2584 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2585 the beginning of the "normal" destination block. If the instruction returns
2586 a value, that value shall set the call or invoke instruction's return
2587 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2589<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2590<pre>
2591 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2592 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2593 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]2594</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2595
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2596<p>Note that the code generator does not yet fully support large
2597 return values. The specific sizes that are currently supported are
2598 dependent on the target. For integers, on 32-bit targets the limit
2599 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2600 For aggregate types, the current limits are dependent on the element
2601 types; for example targets are often limited to 2 total integer
2602 elements and 2 total floating-point elements.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2603
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2604</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2605<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2606<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2607
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2608<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2609
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2610<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2611<pre>
2612 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]2613</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2614
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2615<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2616<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2617 different basic block in the current function. There are two forms of this
2618 instruction, corresponding to a conditional branch and an unconditional
2619 branch.</p>
2620
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2621<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2622<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2623 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2624 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2625 target.</p>
2626
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2627<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2628<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2629 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2630 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2631 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2632
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2633<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2634<pre>
2635Test:
2636 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2637 br i1 %cond, label %IfEqual, label %IfUnequal
2638IfEqual:
2639 <a href="#i_ret">ret</a> i32 1
2640IfUnequal:
2641 <a href="#i_ret">ret</a> i32 0
2642</pre>
2643
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2644</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2645
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2646<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2647<div class="doc_subsubsection">
2648 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2649</div>
2650
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2651<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2652
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2653<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2654<pre>
2655 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2656</pre>
2657
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2658<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2659<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]2660 several different places. It is a generalization of the '<tt>br</tt>'
2661 instruction, allowing a branch to occur to one of many possible
2662 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2663
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2664<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2665<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2666 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2667 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2668 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2669
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2670<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2671<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2672 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2673 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2674 transferred to the corresponding destination; otherwise, control flow is
2675 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2676
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2677<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2678<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2679 <tt>switch</tt> instruction, this instruction may be code generated in
2680 different ways. For example, it could be generated as a series of chained
2681 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2682
2683<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2684<pre>
2685 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2686 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2687 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2688
2689 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2690 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2691
2692 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2693 switch i32 %val, label %otherwise [ i32 0, label %onzero
2694 i32 1, label %onone
2695 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2696</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2697
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2698</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2699
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2700
2701<!-- _______________________________________________________________________ -->
2702<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2703 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2704</div>
2705
2706<div class="doc_text">
2707
2708<h5>Syntax:</h5>
2709<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2710 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]2711</pre>
2712
2713<h5>Overview:</h5>
2714
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2715<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2716 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2717 "<tt>address</tt>". Address must be derived from a <a
2718 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2719
2720<h5>Arguments:</h5>
2721
2722<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2723 rest of the arguments indicate the full set of possible destinations that the
2724 address may point to. Blocks are allowed to occur multiple times in the
2725 destination list, though this isn't particularly useful.</p>
2726
2727<p>This destination list is required so that dataflow analysis has an accurate
2728 understanding of the CFG.</p>
2729
2730<h5>Semantics:</h5>
2731
2732<p>Control transfers to the block specified in the address argument. All
2733 possible destination blocks must be listed in the label list, otherwise this
2734 instruction has undefined behavior. This implies that jumps to labels
2735 defined in other functions have undefined behavior as well.</p>
2736
2737<h5>Implementation:</h5>
2738
2739<p>This is typically implemented with a jump through a register.</p>
2740
2741<h5>Example:</h5>
2742<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2743 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2744</pre>
2745
2746</div>
2747
2748
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2749<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2750<div class="doc_subsubsection">
2751 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2752</div>
2753
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2754<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2755
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2756<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2757<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2758 &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]2759 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2760</pre>
2761
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2762<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2763<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2764 function, with the possibility of control flow transfer to either the
2765 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2766 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2767 control flow will return to the "normal" label. If the callee (or any
2768 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2769 instruction, control is interrupted and continued at the dynamically nearest
2770 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2771
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2772<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2773<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2774
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2775<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2776 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2777 convention</a> the call should use. If none is specified, the call
2778 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2779
2780 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2781 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2782 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2783
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2784 <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]2785 function value being invoked. In most cases, this is a direct function
2786 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2787 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2788
2789 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2790 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2791
2792 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2793 signature argument types. If the function signature indicates the
2794 function accepts a variable number of arguments, the extra arguments can
2795 be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2796
2797 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2798 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2799
2800 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2801 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2802
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2803 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2804 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2805 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2806</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2807
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2808<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2809<p>This instruction is designed to operate as a standard
2810 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2811 primary difference is that it establishes an association with a label, which
2812 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2813
2814<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2815 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2816 exception. Additionally, this is important for implementation of
2817 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2818
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2819<p>For the purposes of the SSA form, the definition of the value returned by the
2820 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2821 block to the "normal" label. If the callee unwinds then no return value is
2822 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]2823
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2824<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2825<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2826 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2827 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2828 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2829 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2830</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2831
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2832</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2833
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2834<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2835
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2836<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2837Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2838
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2839<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2840
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2841<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2842<pre>
2843 unwind
2844</pre>
2845
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2846<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2847<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2848 at the first callee in the dynamic call stack which used
2849 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2850 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2851
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2852<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2853<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2854 immediately halt. The dynamic call stack is then searched for the
2855 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2856 Once found, execution continues at the "exceptional" destination block
2857 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2858 instruction in the dynamic call chain, undefined behavior results.</p>
2859
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2860</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2861
2862<!-- _______________________________________________________________________ -->
2863
2864<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2865Instruction</a> </div>
2866
2867<div class="doc_text">
2868
2869<h5>Syntax:</h5>
2870<pre>
2871 unreachable
2872</pre>
2873
2874<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2875<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2876 instruction is used to inform the optimizer that a particular portion of the
2877 code is not reachable. This can be used to indicate that the code after a
2878 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2879
2880<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2881<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2882
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2883</div>
2884
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2885<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2886<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2887
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2888<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2889
2890<p>Binary operators are used to do most of the computation in a program. They
2891 require two operands of the same type, execute an operation on them, and
2892 produce a single value. The operands might represent multiple data, as is
2893 the case with the <a href="#t_vector">vector</a> data type. The result value
2894 has the same type as its operands.</p>
2895
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2896<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2897
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2898</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2899
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2900<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2901<div class="doc_subsubsection">
2902 <a name="i_add">'<tt>add</tt>' Instruction</a>
2903</div>
2904
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2905<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2906
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2907<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2908<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2909 &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]2910 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2911 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2912 &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]2913</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2914
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2915<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2916<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2917
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2918<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2919<p>The two arguments to the '<tt>add</tt>' instruction must
2920 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2921 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2922
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2923<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2924<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2925
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2926<p>If the sum has unsigned overflow, the result returned is the mathematical
2927 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]2928
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2929<p>Because LLVM integers use a two's complement representation, this instruction
2930 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2931
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2932<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2933 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2934 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2935 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2937<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2938<pre>
2939 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2940</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2941
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2942</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2943
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2944<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2945<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2946 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2947</div>
2948
2949<div class="doc_text">
2950
2951<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2952<pre>
2953 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2954</pre>
2955
2956<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2957<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2958
2959<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2960<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2961 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2962 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2963
2964<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2965<p>The value produced is the floating point sum of the two operands.</p>
2966
2967<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2968<pre>
2969 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2970</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2971
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2972</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2973
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2974<!-- _______________________________________________________________________ -->
2975<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2976 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2977</div>
2978
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2979<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2980
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2981<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2982<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2983 &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]2984 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2985 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2986 &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]2987</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2989<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2990<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2991 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2992
2993<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2994 '<tt>neg</tt>' instruction present in most other intermediate
2995 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2996
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2997<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2998<p>The two arguments to the '<tt>sub</tt>' instruction must
2999 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3000 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3001
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3002<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3003<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3004
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3005<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3006 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3007 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3008
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3009<p>Because LLVM integers use a two's complement representation, this instruction
3010 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3011
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3012<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3013 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3014 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3015 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3016
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3017<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3018<pre>
3019 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3020 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3021</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3022
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3023</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3024
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3025<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3026<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3027 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3028</div>
3029
3030<div class="doc_text">
3031
3032<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3033<pre>
3034 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3035</pre>
3036
3037<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3038<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3039 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3040
3041<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3042 '<tt>fneg</tt>' instruction present in most other intermediate
3043 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3044
3045<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3046<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3047 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3048 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3049
3050<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3051<p>The value produced is the floating point difference of the two operands.</p>
3052
3053<h5>Example:</h5>
3054<pre>
3055 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3056 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3057</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3058
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3059</div>
3060
3061<!-- _______________________________________________________________________ -->
3062<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3063 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3064</div>
3065
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3066<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3067
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3068<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3069<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3070 &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]3071 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3072 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3073 &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]3074</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3075
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3076<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3077<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3078
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3079<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3080<p>The two arguments to the '<tt>mul</tt>' instruction must
3081 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3082 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3083
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3084<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3085<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3086
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3087<p>If the result of the multiplication has unsigned overflow, the result
3088 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3089 width of the result.</p>
3090
3091<p>Because LLVM integers use a two's complement representation, and the result
3092 is the same width as the operands, this instruction returns the correct
3093 result for both signed and unsigned integers. If a full product
3094 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3095 be sign-extended or zero-extended as appropriate to the width of the full
3096 product.</p>
3097
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3098<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3099 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3100 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3101 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3102
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3103<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3104<pre>
3105 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3106</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3107
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3108</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3109
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3110<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3111<div class="doc_subsubsection">
3112 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3113</div>
3114
3115<div class="doc_text">
3116
3117<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3118<pre>
3119 &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]3120</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3121
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3122<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3123<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3124
3125<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3126<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3127 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3128 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3129
3130<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3131<p>The value produced is the floating point product of the two operands.</p>
3132
3133<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3134<pre>
3135 &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]3136</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3137
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3138</div>
3139
3140<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3141<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3142</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3143
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3144<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3145
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3146<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3147<pre>
3148 &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]3149</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3150
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3151<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3153
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3154<h5>Arguments:</h5>
3155<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3156 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3157 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3158
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3159<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3160<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3161
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3162<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3163 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3164
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3165<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3166
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3167<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3168<pre>
3169 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3170</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3171
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3172</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3173
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3174<!-- _______________________________________________________________________ -->
3175<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3176</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3177
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3178<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3179
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3180<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3181<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3182 &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]3183 &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]3184</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3185
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3186<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3187<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3188
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3189<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3190<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3191 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3192 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3193
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3194<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3195<p>The value produced is the signed integer quotient of the two operands rounded
3196 towards zero.</p>
3197
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3198<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3199 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3200
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3201<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3202 undefined behavior; this is a rare case, but can occur, for example, by doing
3203 a 32-bit division of -2147483648 by -1.</p>
3204
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3205<p>If the <tt>exact</tt> keyword is present, the result value of the
3206 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3207 would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3208
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3209<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3210<pre>
3211 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3212</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3213
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3214</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3215
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3216<!-- _______________________________________________________________________ -->
3217<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3218Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3219
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3220<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3221
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3222<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3223<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3224 &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]3225</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3226
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3227<h5>Overview:</h5>
3228<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3229
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3230<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3231<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3232 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3233 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3234
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3235<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3236<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3237
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3238<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3239<pre>
3240 &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]3241</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3242
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3243</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3244
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3245<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3246<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3247</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3248
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3249<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3250
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3251<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3252<pre>
3253 &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]3254</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3255
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3256<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3257<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3258 division of its two arguments.</p>
3259
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3260<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3261<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3262 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3263 values. Both arguments must have identical types.</p>
3264
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3265<h5>Semantics:</h5>
3266<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3267 This instruction always performs an unsigned division to get the
3268 remainder.</p>
3269
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3270<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3271 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3272
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3273<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3274
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3275<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3276<pre>
3277 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3278</pre>
3279
3280</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3281
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3282<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3283<div class="doc_subsubsection">
3284 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3285</div>
3286
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3287<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3288
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3289<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3290<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3291 &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]3292</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3293
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3294<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3295<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3296 division of its two operands. This instruction can also take
3297 <a href="#t_vector">vector</a> versions of the values in which case the
3298 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3299
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3300<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3301<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3302 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3303 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3304
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3305<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3306<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3307 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3308 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3309 a value. For more information about the difference,
3310 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3311 Math Forum</a>. For a table of how this is implemented in various languages,
3312 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3313 Wikipedia: modulo operation</a>.</p>
3314
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3315<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3316 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3317
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3318<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3319 Overflow also leads to undefined behavior; this is a rare case, but can
3320 occur, for example, by taking the remainder of a 32-bit division of
3321 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3322 lets srem be implemented using instructions that return both the result of
3323 the division and the remainder.)</p>
3324
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3325<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3326<pre>
3327 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3328</pre>
3329
3330</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3331
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3332<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3333<div class="doc_subsubsection">
3334 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3335
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3336<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3337
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3338<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3339<pre>
3340 &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]3341</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3342
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3343<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3344<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3345 its two operands.</p>
3346
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3347<h5>Arguments:</h5>
3348<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3349 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3350 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3351
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3352<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3353<p>This instruction returns the <i>remainder</i> of a division. The remainder
3354 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3355
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3356<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3357<pre>
3358 &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]3359</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3360
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3361</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3362
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3363<!-- ======================================================================= -->
3364<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3365Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3366
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3367<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3368
3369<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3370 program. They are generally very efficient instructions and can commonly be
3371 strength reduced from other instructions. They require two operands of the
3372 same type, execute an operation on them, and produce a single value. The
3373 resulting value is the same type as its operands.</p>
3374
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3375</div>
3376
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3377<!-- _______________________________________________________________________ -->
3378<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3379Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3380
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3381<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3382
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3383<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3384<pre>
3385 &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]3386</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3387
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3388<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3389<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3390 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3391
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3392<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3393<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3394 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3395 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3396
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3397<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3398<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3399 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3400 is (statically or dynamically) negative or equal to or larger than the number
3401 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3402 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3403 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3404
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3405<h5>Example:</h5>
3406<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3407 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3408 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3409 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3410 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3411 &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]3412</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3413
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3414</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3415
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3416<!-- _______________________________________________________________________ -->
3417<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3418Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3419
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3420<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3421
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3422<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3423<pre>
3424 &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]3425</pre>
3426
3427<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3428<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3429 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3430
3431<h5>Arguments:</h5>
3432<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3433 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3434 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3435
3436<h5>Semantics:</h5>
3437<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3438 significant bits of the result will be filled with zero bits after the shift.
3439 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3440 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3441 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3442 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3443
3444<h5>Example:</h5>
3445<pre>
3446 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3447 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3448 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3449 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3450 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3451 &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]3452</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3453
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3454</div>
3455
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3456<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3457<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3458Instruction</a> </div>
3459<div class="doc_text">
3460
3461<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3462<pre>
3463 &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]3464</pre>
3465
3466<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3467<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3468 operand shifted to the right a specified number of bits with sign
3469 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3470
3471<h5>Arguments:</h5>
3472<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3473 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3474 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3475
3476<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3477<p>This instruction always performs an arithmetic shift right operation, The
3478 most significant bits of the result will be filled with the sign bit
3479 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3480 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3481 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3482 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3483
3484<h5>Example:</h5>
3485<pre>
3486 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3487 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3488 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3489 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3490 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3491 &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]3492</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3493
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3494</div>
3495
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3496<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3497<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3498Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3499
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3500<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3501
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3502<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3503<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3504 &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]3505</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3506
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3507<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3509 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3510
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3511<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3512<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3513 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3514 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3515
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3516<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3517<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3518
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3519<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3520 <tbody>
3521 <tr>
3522 <td>In0</td>
3523 <td>In1</td>
3524 <td>Out</td>
3525 </tr>
3526 <tr>
3527 <td>0</td>
3528 <td>0</td>
3529 <td>0</td>
3530 </tr>
3531 <tr>
3532 <td>0</td>
3533 <td>1</td>
3534 <td>0</td>
3535 </tr>
3536 <tr>
3537 <td>1</td>
3538 <td>0</td>
3539 <td>0</td>
3540 </tr>
3541 <tr>
3542 <td>1</td>
3543 <td>1</td>
3544 <td>1</td>
3545 </tr>
3546 </tbody>
3547</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3548
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3549<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3550<pre>
3551 &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]3552 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3553 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3554</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3555</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3556<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3557<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3558
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3559<div class="doc_text">
3560
3561<h5>Syntax:</h5>
3562<pre>
3563 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3564</pre>
3565
3566<h5>Overview:</h5>
3567<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3568 two operands.</p>
3569
3570<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3571<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3572 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3573 values. Both arguments must have identical types.</p>
3574
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3575<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3576<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3577
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3578<table border="1" cellspacing="0" cellpadding="4">
3579 <tbody>
3580 <tr>
3581 <td>In0</td>
3582 <td>In1</td>
3583 <td>Out</td>
3584 </tr>
3585 <tr>
3586 <td>0</td>
3587 <td>0</td>
3588 <td>0</td>
3589 </tr>
3590 <tr>
3591 <td>0</td>
3592 <td>1</td>
3593 <td>1</td>
3594 </tr>
3595 <tr>
3596 <td>1</td>
3597 <td>0</td>
3598 <td>1</td>
3599 </tr>
3600 <tr>
3601 <td>1</td>
3602 <td>1</td>
3603 <td>1</td>
3604 </tr>
3605 </tbody>
3606</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3607
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3608<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3609<pre>
3610 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3611 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3612 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3613</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3614
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3615</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3616
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3617<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3618<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3619Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3620
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3621<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3622
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3623<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3624<pre>
3625 &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]3626</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3627
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3628<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3629<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3630 its two operands. The <tt>xor</tt> is used to implement the "one's
3631 complement" operation, which is the "~" operator in C.</p>
3632
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3633<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3634<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3635 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3636 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3637
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3638<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3639<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3640
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3641<table border="1" cellspacing="0" cellpadding="4">
3642 <tbody>
3643 <tr>
3644 <td>In0</td>
3645 <td>In1</td>
3646 <td>Out</td>
3647 </tr>
3648 <tr>
3649 <td>0</td>
3650 <td>0</td>
3651 <td>0</td>
3652 </tr>
3653 <tr>
3654 <td>0</td>
3655 <td>1</td>
3656 <td>1</td>
3657 </tr>
3658 <tr>
3659 <td>1</td>
3660 <td>0</td>
3661 <td>1</td>
3662 </tr>
3663 <tr>
3664 <td>1</td>
3665 <td>1</td>
3666 <td>0</td>
3667 </tr>
3668 </tbody>
3669</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3670
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3671<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3672<pre>
3673 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3674 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3675 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3676 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3677</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3678
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3679</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3680
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3681<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3682<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3683 <a name="vectorops">Vector Operations</a>
3684</div>
3685
3686<div class="doc_text">
3687
3688<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3689 target-independent manner. These instructions cover the element-access and
3690 vector-specific operations needed to process vectors effectively. While LLVM
3691 does directly support these vector operations, many sophisticated algorithms
3692 will want to use target-specific intrinsics to take full advantage of a
3693 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3694
3695</div>
3696
3697<!-- _______________________________________________________________________ -->
3698<div class="doc_subsubsection">
3699 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3700</div>
3701
3702<div class="doc_text">
3703
3704<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3705<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3706 &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]3707</pre>
3708
3709<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3710<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3711 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3712
3713
3714<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3715<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3716 of <a href="#t_vector">vector</a> type. The second operand is an index
3717 indicating the position from which to extract the element. The index may be
3718 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3719
3720<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3721<p>The result is a scalar of the same type as the element type of
3722 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3723 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3724 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3725
3726<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3727<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3728 &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]3729</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3730
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3731</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3732
3733<!-- _______________________________________________________________________ -->
3734<div class="doc_subsubsection">
3735 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3736</div>
3737
3738<div class="doc_text">
3739
3740<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3741<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]3742 &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]3743</pre>
3744
3745<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3746<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3747 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3748
3749<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3750<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3751 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3752 whose type must equal the element type of the first operand. The third
3753 operand is an index indicating the position at which to insert the value.
3754 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3755
3756<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3757<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3758 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3759 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3760 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3761
3762<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3763<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3764 &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]3765</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3766
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3767</div>
3768
3769<!-- _______________________________________________________________________ -->
3770<div class="doc_subsubsection">
3771 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3772</div>
3773
3774<div class="doc_text">
3775
3776<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3777<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3778 &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]3779</pre>
3780
3781<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3782<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3783 from two input vectors, returning a vector with the same element type as the
3784 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3785
3786<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3787<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3788 with types that match each other. The third argument is a shuffle mask whose
3789 element type is always 'i32'. The result of the instruction is a vector
3790 whose length is the same as the shuffle mask and whose element type is the
3791 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3792
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3793<p>The shuffle mask operand is required to be a constant vector with either
3794 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3795
3796<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3797<p>The elements of the two input vectors are numbered from left to right across
3798 both of the vectors. The shuffle mask operand specifies, for each element of
3799 the result vector, which element of the two input vectors the result element
3800 gets. The element selector may be undef (meaning "don't care") and the
3801 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3802
3803<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3804<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3805 &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]3806 &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]3807 &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]3808 &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]3809 &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]3810 &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]3811 &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]3812 &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]3813</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3814
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3815</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]3816
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3817<!-- ======================================================================= -->
3818<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3819 <a name="aggregateops">Aggregate Operations</a>
3820</div>
3821
3822<div class="doc_text">
3823
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3824<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3825
3826</div>
3827
3828<!-- _______________________________________________________________________ -->
3829<div class="doc_subsubsection">
3830 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3831</div>
3832
3833<div class="doc_text">
3834
3835<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3836<pre>
3837 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3838</pre>
3839
3840<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3841<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3842 or array element from an aggregate value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3843
3844<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3845<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3846 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3847 operands are constant indices to specify which value to extract in a similar
3848 manner as indices in a
3849 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3850
3851<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3852<p>The result is the value at the position in the aggregate specified by the
3853 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3854
3855<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3856<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3857 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3858</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3859
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3860</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3861
3862<!-- _______________________________________________________________________ -->
3863<div class="doc_subsubsection">
3864 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3865</div>
3866
3867<div class="doc_text">
3868
3869<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3870<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3871 &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]3872</pre>
3873
3874<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3875<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3876 array element in an aggregate.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3877
3878
3879<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3880<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3881 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3882 second operand is a first-class value to insert. The following operands are
3883 constant indices indicating the position at which to insert the value in a
3884 similar manner as indices in a
3885 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3886 value to insert must have the same type as the value identified by the
3887 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3888
3889<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3890<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3891 that of <tt>val</tt> except that the value at the position specified by the
3892 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3893
3894<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3895<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3896 &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]3897</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3898
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3899</div>
3900
3901
3902<!-- ======================================================================= -->
3903<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3904 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3905</div>
3906
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3907<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3908
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3909<p>A key design point of an SSA-based representation is how it represents
3910 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]3911 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3912 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3913
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3914</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3915
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3916<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3917<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3918 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3919</div>
3920
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3921<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3922
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3923<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3924<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3925 &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]3926</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3927
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3928<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3929<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3930 currently executing function, to be automatically released when this function
3931 returns to its caller. The object is always allocated in the generic address
3932 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3933
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3934<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3935<p>The '<tt>alloca</tt>' instruction
3936 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3937 runtime stack, returning a pointer of the appropriate type to the program.
3938 If "NumElements" is specified, it is the number of elements allocated,
3939 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3940 specified, the value result of the allocation is guaranteed to be aligned to
3941 at least that boundary. If not specified, or if zero, the target can choose
3942 to align the allocation on any convenient boundary compatible with the
3943 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3944
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3945<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3946
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3947<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]3948<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3949 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3950 memory is automatically released when the function returns. The
3951 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3952 variables that must have an address available. When the function returns
3953 (either with the <tt><a href="#i_ret">ret</a></tt>
3954 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3955 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3956
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3957<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3958<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3959 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3960 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3961 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3962 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3963</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3964
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3965</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3966
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3967<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3968<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3969Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3970
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3971<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3972
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3973<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3974<pre>
3975 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3976 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3977</pre>
3978
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3979<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3980<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3981
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3982<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3983<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3984 from which to load. The pointer must point to
3985 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3986 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3987 number or order of execution of this <tt>load</tt> with other
3988 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3989 instructions. </p>
3990
3991<p>The optional constant "align" argument specifies the alignment of the
3992 operation (that is, the alignment of the memory address). A value of 0 or an
3993 omitted "align" argument means that the operation has the preferential
3994 alignment for the target. It is the responsibility of the code emitter to
3995 ensure that the alignment information is correct. Overestimating the
3996 alignment results in an undefined behavior. Underestimating the alignment may
3997 produce less efficient code. An alignment of 1 is always safe.</p>
3998
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3999<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4000<p>The location of memory pointed to is loaded. If the value being loaded is of
4001 scalar type then the number of bytes read does not exceed the minimum number
4002 of bytes needed to hold all bits of the type. For example, loading an
4003 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4004 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4005 is undefined if the value was not originally written using a store of the
4006 same type.</p>
4007
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4008<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4009<pre>
4010 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4011 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4012 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4013</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4014
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4015</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4016
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4017<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4018<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4019Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4020
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4021<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4022
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4023<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4024<pre>
4025 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]4026 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]4027</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4028
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4029<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4030<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4031
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4032<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4033<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4034 and an address at which to store it. The type of the
4035 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4036 the <a href="#t_firstclass">first class</a> type of the
4037 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4038 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4039 or order of execution of this <tt>store</tt> with other
4040 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4041 instructions.</p>
4042
4043<p>The optional constant "align" argument specifies the alignment of the
4044 operation (that is, the alignment of the memory address). A value of 0 or an
4045 omitted "align" argument means that the operation has the preferential
4046 alignment for the target. It is the responsibility of the code emitter to
4047 ensure that the alignment information is correct. Overestimating the
4048 alignment results in an undefined behavior. Underestimating the alignment may
4049 produce less efficient code. An alignment of 1 is always safe.</p>
4050
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4051<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4052<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4053 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4054 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4055 does not exceed the minimum number of bytes needed to hold all bits of the
4056 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4057 writing a value of a type like <tt>i20</tt> with a size that is not an
4058 integral number of bytes, it is unspecified what happens to the extra bits
4059 that do not belong to the type, but they will typically be overwritten.</p>
4060
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4061<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062<pre>
4063 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4064 store i32 3, i32* %ptr <i>; yields {void}</i>
4065 %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]4066</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4067
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4068</div>
4069
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4070<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4071<div class="doc_subsubsection">
4072 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4073</div>
4074
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4075<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4076
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4077<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4078<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4079 &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]4080 &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]4081</pre>
4082
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4083<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4084<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4085 subelement of an aggregate data structure. It performs address calculation
4086 only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4087
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4088<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4089<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4090 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4091 elements of the aggregate object are indexed. The interpretation of each
4092 index is dependent on the type being indexed into. The first index always
4093 indexes the pointer value given as the first argument, the second index
4094 indexes a value of the type pointed to (not necessarily the value directly
4095 pointed to, since the first index can be non-zero), etc. The first type
4096 indexed into must be a pointer value, subsequent types can be arrays, vectors
4097 and structs. Note that subsequent types being indexed into can never be
4098 pointers, since that would require loading the pointer before continuing
4099 calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4100
4101<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]4102 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4103 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4104 vector, integers of any width are allowed, and they are not required to be
4105 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4106
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4107<p>For example, let's consider a C code fragment and how it gets compiled to
4108 LLVM:</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>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4112struct RT {
4113 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4114 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4115 char C;
4116};
4117struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4118 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4119 double Y;
4120 struct RT Z;
4121};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4122
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4123int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4124 return &amp;s[1].Z.B[5][13];
4125}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4126</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4127</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4128
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4129<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4130
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4131<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4132<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4133%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4134%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4135
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4136define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4137entry:
4138 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4139 ret i32* %reg
4140}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4141</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4142</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4143
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4144<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4145<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]4146 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4147 }</tt>' type, a structure. The second index indexes into the third element
4148 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4149 i8 }</tt>' type, another structure. The third index indexes into the second
4150 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4151 array. The two dimensions of the array are subscripted into, yielding an
4152 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4153 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4154
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4155<p>Note that it is perfectly legal to index partially through a structure,
4156 returning a pointer to an inner element. Because of this, the LLVM code for
4157 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4158
4159<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4160 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4161 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4162 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4163 %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]4164 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4165 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4166 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4167 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4168</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4169
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4170<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4171 <tt>getelementptr</tt> is undefined if the base pointer is not an
4172 <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]4173 that would be formed by successive addition of the offsets implied by the
4174 indices to the base address with infinitely precise arithmetic are not an
4175 <i>in bounds</i> address of that allocated object.
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4176 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4177 that point into the object, plus the address one byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4178
4179<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4180 the base address with silently-wrapping two's complement arithmetic, and
4181 the result value of the <tt>getelementptr</tt> may be outside the object
4182 pointed to by the base pointer. The result value may not necessarily be
4183 used to access memory though, even if it happens to point into allocated
4184 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4185 section for more information.</p>
4186
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4187<p>The getelementptr instruction is often confusing. For some more insight into
4188 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4189
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4190<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4191<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4192 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4193 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4194 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4195 %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]4196 <i>; yields i8*:eptr</i>
4197 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4198 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4199 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4200</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4201
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4202</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4203
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4204<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4205<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4206</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4207
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4208<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4209
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4210<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4211 which all take a single operand and a type. They perform various bit
4212 conversions on the operand.</p>
4213
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4214</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4215
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4216<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4217<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4218 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4219</div>
4220<div class="doc_text">
4221
4222<h5>Syntax:</h5>
4223<pre>
4224 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4225</pre>
4226
4227<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4228<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4229 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4230
4231<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4232<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4233 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4234 size and type of the result, which must be
4235 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4236 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4237 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4238
4239<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4240<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4241 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4242 source size must be larger than the destination size, <tt>trunc</tt> cannot
4243 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4244
4245<h5>Example:</h5>
4246<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4247 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4248 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4249 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4250</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4251
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4252</div>
4253
4254<!-- _______________________________________________________________________ -->
4255<div class="doc_subsubsection">
4256 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4257</div>
4258<div class="doc_text">
4259
4260<h5>Syntax:</h5>
4261<pre>
4262 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4263</pre>
4264
4265<h5>Overview:</h5>
4266<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4267 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4268
4269
4270<h5>Arguments:</h5>
4271<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]4272 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4273 also be of <a href="#t_integer">integer</a> type. The bit size of the
4274 <tt>value</tt> must be smaller than the bit size of the destination type,
4275 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4276
4277<h5>Semantics:</h5>
4278<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]4279 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4280
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4281<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]4282
4283<h5>Example:</h5>
4284<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4285 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4286 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4287</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4288
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4289</div>
4290
4291<!-- _______________________________________________________________________ -->
4292<div class="doc_subsubsection">
4293 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4294</div>
4295<div class="doc_text">
4296
4297<h5>Syntax:</h5>
4298<pre>
4299 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4300</pre>
4301
4302<h5>Overview:</h5>
4303<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4304
4305<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4306<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4307 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4308 also be of <a href="#t_integer">integer</a> type. The bit size of the
4309 <tt>value</tt> must be smaller than the bit size of the destination type,
4310 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4311
4312<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4313<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4314 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4315 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4316
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4317<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]4318
4319<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4320<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4321 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4322 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4323</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4324
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4325</div>
4326
4327<!-- _______________________________________________________________________ -->
4328<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4329 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4330</div>
4331
4332<div class="doc_text">
4333
4334<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4335<pre>
4336 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4337</pre>
4338
4339<h5>Overview:</h5>
4340<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4341 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4342
4343<h5>Arguments:</h5>
4344<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4345 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4346 to cast it to. The size of <tt>value</tt> must be larger than the size of
4347 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4348 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4349
4350<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4351<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4352 <a href="#t_floating">floating point</a> type to a smaller
4353 <a href="#t_floating">floating point</a> type. If the value cannot fit
4354 within the destination type, <tt>ty2</tt>, then the results are
4355 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4356
4357<h5>Example:</h5>
4358<pre>
4359 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4360 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4361</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4362
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4363</div>
4364
4365<!-- _______________________________________________________________________ -->
4366<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4367 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4368</div>
4369<div class="doc_text">
4370
4371<h5>Syntax:</h5>
4372<pre>
4373 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4374</pre>
4375
4376<h5>Overview:</h5>
4377<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]4378 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4379
4380<h5>Arguments:</h5>
4381<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4382 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4383 a <a href="#t_floating">floating point</a> type to cast it to. The source
4384 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4385
4386<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4387<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4388 <a href="#t_floating">floating point</a> type to a larger
4389 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4390 used to make a <i>no-op cast</i> because it always changes bits. Use
4391 <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]4392
4393<h5>Example:</h5>
4394<pre>
4395 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4396 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4397</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4398
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4399</div>
4400
4401<!-- _______________________________________________________________________ -->
4402<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4403 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4404</div>
4405<div class="doc_text">
4406
4407<h5>Syntax:</h5>
4408<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4409 &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]4410</pre>
4411
4412<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4413<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4414 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4415
4416<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4417<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4418 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4419 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4420 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4421 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4422
4423<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4424<p>The '<tt>fptoui</tt>' instruction converts its
4425 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4426 towards zero) unsigned integer value. If the value cannot fit
4427 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4428
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4429<h5>Example:</h5>
4430<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4431 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4432 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4433 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4434</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4435
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4436</div>
4437
4438<!-- _______________________________________________________________________ -->
4439<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4440 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4441</div>
4442<div class="doc_text">
4443
4444<h5>Syntax:</h5>
4445<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4446 &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]4447</pre>
4448
4449<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4450<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4451 <a href="#t_floating">floating point</a> <tt>value</tt> to
4452 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4453
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4454<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4455<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4456 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4457 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4458 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4459 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4460
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4461<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4462<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4463 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4464 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4465 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4466
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4467<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4468<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4469 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4470 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4471 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4472</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4473
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4474</div>
4475
4476<!-- _______________________________________________________________________ -->
4477<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4478 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4479</div>
4480<div class="doc_text">
4481
4482<h5>Syntax:</h5>
4483<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4484 &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]4485</pre>
4486
4487<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4488<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4489 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4490
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4491<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4492<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]4493 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4494 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4495 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4496 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4497
4498<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4499<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4500 integer quantity and converts it to the corresponding floating point
4501 value. If the value cannot fit in the floating point value, the results are
4502 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4503
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4504<h5>Example:</h5>
4505<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4506 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4507 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4508</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4509
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4510</div>
4511
4512<!-- _______________________________________________________________________ -->
4513<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4514 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4515</div>
4516<div class="doc_text">
4517
4518<h5>Syntax:</h5>
4519<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4520 &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]4521</pre>
4522
4523<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4524<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4525 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4526
4527<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4528<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]4529 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4530 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4531 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4532 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4533
4534<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4535<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4536 quantity and converts it to the corresponding floating point value. If the
4537 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4538
4539<h5>Example:</h5>
4540<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4541 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4542 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4543</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4544
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4545</div>
4546
4547<!-- _______________________________________________________________________ -->
4548<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4549 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4550</div>
4551<div class="doc_text">
4552
4553<h5>Syntax:</h5>
4554<pre>
4555 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4556</pre>
4557
4558<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4559<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4560 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4561
4562<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4563<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4564 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4565 <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]4566
4567<h5>Semantics:</h5>
4568<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4569 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4570 truncating or zero extending that value to the size of the integer type. If
4571 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4572 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4573 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4574 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4575
4576<h5>Example:</h5>
4577<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4578 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4579 %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]4580</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4581
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4582</div>
4583
4584<!-- _______________________________________________________________________ -->
4585<div class="doc_subsubsection">
4586 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4587</div>
4588<div class="doc_text">
4589
4590<h5>Syntax:</h5>
4591<pre>
4592 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4593</pre>
4594
4595<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4596<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4597 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4598
4599<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4600<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4601 value to cast, and a type to cast it to, which must be a
4602 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4603
4604<h5>Semantics:</h5>
4605<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4606 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4607 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4608 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4609 than the size of a pointer then a zero extension is done. If they are the
4610 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4611
4612<h5>Example:</h5>
4613<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4614 %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]4615 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4616 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4617</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4618
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4619</div>
4620
4621<!-- _______________________________________________________________________ -->
4622<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4623 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4624</div>
4625<div class="doc_text">
4626
4627<h5>Syntax:</h5>
4628<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4629 &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]4630</pre>
4631
4632<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4633<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4634 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4635
4636<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4637<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4638 non-aggregate first class value, and a type to cast it to, which must also be
4639 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4640 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4641 identical. If the source type is a pointer, the destination type must also be
4642 a pointer. This instruction supports bitwise conversion of vectors to
4643 integers and to vectors of other types (as long as they have the same
4644 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4645
4646<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4647<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4648 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4649 this conversion. The conversion is done as if the <tt>value</tt> had been
4650 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4651 be converted to other pointer types with this instruction. To convert
4652 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4653 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4654
4655<h5>Example:</h5>
4656<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4657 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4658 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4659 %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]4660</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4661
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4662</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4663
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4664<!-- ======================================================================= -->
4665<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4666
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4667<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4668
4669<p>The instructions in this category are the "miscellaneous" instructions, which
4670 defy better classification.</p>
4671
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4672</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4673
4674<!-- _______________________________________________________________________ -->
4675<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4676</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4677
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4678<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4679
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4680<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4681<pre>
4682 &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]4683</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4684
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4685<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4686<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4687 boolean values based on comparison of its two integer, integer vector, or
4688 pointer operands.</p>
4689
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4690<h5>Arguments:</h5>
4691<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4692 the condition code indicating the kind of comparison to perform. It is not a
4693 value, just a keyword. The possible condition code are:</p>
4694
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4695<ol>
4696 <li><tt>eq</tt>: equal</li>
4697 <li><tt>ne</tt>: not equal </li>
4698 <li><tt>ugt</tt>: unsigned greater than</li>
4699 <li><tt>uge</tt>: unsigned greater or equal</li>
4700 <li><tt>ult</tt>: unsigned less than</li>
4701 <li><tt>ule</tt>: unsigned less or equal</li>
4702 <li><tt>sgt</tt>: signed greater than</li>
4703 <li><tt>sge</tt>: signed greater or equal</li>
4704 <li><tt>slt</tt>: signed less than</li>
4705 <li><tt>sle</tt>: signed less or equal</li>
4706</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4707
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4708<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4709 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4710 typed. They must also be identical types.</p>
4711
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4712<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4713<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4714 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4715 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]4716 result, as follows:</p>
4717
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4718<ol>
4719 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4720 <tt>false</tt> otherwise. No sign interpretation is necessary or
4721 performed.</li>
4722
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4723 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4724 <tt>false</tt> otherwise. No sign interpretation is necessary or
4725 performed.</li>
4726
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4727 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4728 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4729
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4730 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4731 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4732 to <tt>op2</tt>.</li>
4733
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4734 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4735 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4736
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4737 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4738 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4739
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4740 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4742
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4743 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4744 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4745 to <tt>op2</tt>.</li>
4746
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4747 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4748 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4749
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4750 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4751 <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]4752</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4753
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4754<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4755 values are compared as if they were integers.</p>
4756
4757<p>If the operands are integer vectors, then they are compared element by
4758 element. The result is an <tt>i1</tt> vector with the same number of elements
4759 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4760
4761<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4762<pre>
4763 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4764 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4765 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4766 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4767 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4768 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4769</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4770
4771<p>Note that the code generator does not yet support vector types with
4772 the <tt>icmp</tt> instruction.</p>
4773
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4774</div>
4775
4776<!-- _______________________________________________________________________ -->
4777<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4778</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4779
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4780<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4781
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4782<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4783<pre>
4784 &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]4785</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4786
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4787<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4788<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4789 values based on comparison of its operands.</p>
4790
4791<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]4792(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4793
4794<p>If the operands are floating point vectors, then the result type is a vector
4795 of boolean with the same number of elements as the operands being
4796 compared.</p>
4797
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4798<h5>Arguments:</h5>
4799<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4800 the condition code indicating the kind of comparison to perform. It is not a
4801 value, just a keyword. The possible condition code are:</p>
4802
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4803<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4804 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4805 <li><tt>oeq</tt>: ordered and equal</li>
4806 <li><tt>ogt</tt>: ordered and greater than </li>
4807 <li><tt>oge</tt>: ordered and greater than or equal</li>
4808 <li><tt>olt</tt>: ordered and less than </li>
4809 <li><tt>ole</tt>: ordered and less than or equal</li>
4810 <li><tt>one</tt>: ordered and not equal</li>
4811 <li><tt>ord</tt>: ordered (no nans)</li>
4812 <li><tt>ueq</tt>: unordered or equal</li>
4813 <li><tt>ugt</tt>: unordered or greater than </li>
4814 <li><tt>uge</tt>: unordered or greater than or equal</li>
4815 <li><tt>ult</tt>: unordered or less than </li>
4816 <li><tt>ule</tt>: unordered or less than or equal</li>
4817 <li><tt>une</tt>: unordered or not equal</li>
4818 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4819 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4820</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4821
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4822<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4823 <i>unordered</i> means that either operand may be a QNAN.</p>
4824
4825<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4826 a <a href="#t_floating">floating point</a> type or
4827 a <a href="#t_vector">vector</a> of floating point type. They must have
4828 identical types.</p>
4829
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4830<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4831<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4832 according to the condition code given as <tt>cond</tt>. If the operands are
4833 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4834 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4835 follows:</p>
4836
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4837<ol>
4838 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4839
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4840 <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]4841 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4842
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4843 <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]4844 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4845
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4846 <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]4847 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4848
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4849 <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]4850 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4851
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4852 <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]4853 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4854
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4855 <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]4856 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4857
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4858 <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]4859
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4860 <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]4861 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4862
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4863 <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]4864 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4865
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4866 <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]4867 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4868
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4869 <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]4870 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4871
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4872 <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]4873 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4874
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4875 <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]4876 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4877
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4878 <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]4879
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4880 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4881</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4882
4883<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4884<pre>
4885 &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]4886 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4887 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4888 &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]4889</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4890
4891<p>Note that the code generator does not yet support vector types with
4892 the <tt>fcmp</tt> instruction.</p>
4893
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4894</div>
4895
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4896<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]4897<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4898 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4899</div>
4900
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4901<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4902
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4903<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4904<pre>
4905 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4906</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4907
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4908<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4909<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4910 SSA graph representing the function.</p>
4911
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4912<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4913<p>The type of the incoming values is specified with the first type field. After
4914 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4915 one pair for each predecessor basic block of the current block. Only values
4916 of <a href="#t_firstclass">first class</a> type may be used as the value
4917 arguments to the PHI node. Only labels may be used as the label
4918 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4919
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4920<p>There must be no non-phi instructions between the start of a basic block and
4921 the PHI instructions: i.e. PHI instructions must be first in a basic
4922 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4923
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4924<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4925 occur on the edge from the corresponding predecessor block to the current
4926 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4927 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]4928
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4929<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4930<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4931 specified by the pair corresponding to the predecessor basic block that
4932 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4933
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4934<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4935<pre>
4936Loop: ; Infinite loop that counts from 0 on up...
4937 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4938 %nextindvar = add i32 %indvar, 1
4939 br label %Loop
4940</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4941
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4942</div>
4943
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4944<!-- _______________________________________________________________________ -->
4945<div class="doc_subsubsection">
4946 <a name="i_select">'<tt>select</tt>' Instruction</a>
4947</div>
4948
4949<div class="doc_text">
4950
4951<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4952<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4953 &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>
4954
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4955 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4956</pre>
4957
4958<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4959<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4960 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4961
4962
4963<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4964<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4965 values indicating the condition, and two values of the
4966 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4967 vectors and the condition is a scalar, then entire vectors are selected, not
4968 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4969
4970<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4971<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4972 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4973
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4974<p>If the condition is a vector of i1, then the value arguments must be vectors
4975 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4976
4977<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4978<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4979 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4980</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4981
4982<p>Note that the code generator does not yet support conditions
4983 with vector type.</p>
4984
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4985</div>
4986
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]4987<!-- _______________________________________________________________________ -->
4988<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4989 <a name="i_call">'<tt>call</tt>' Instruction</a>
4990</div>
4991
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4992<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4993
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4994<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4995<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]4996 &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]4997</pre>
4998
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4999<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5000<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5001
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5002<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5003<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5004
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5005<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5006 <li>The optional "tail" marker indicates whether the callee function accesses
5007 any allocas or varargs in the caller. If the "tail" marker is present,
5008 the function call is eligible for tail call optimization. Note that calls
5009 may be marked "tail" even if they do not occur before
5010 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5011
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5012 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5013 convention</a> the call should use. If none is specified, the call
5014 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5015
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5016 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5017 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5018 '<tt>inreg</tt>' attributes are valid here.</li>
5019
5020 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5021 type of the return value. Functions that return no value are marked
5022 <tt><a href="#t_void">void</a></tt>.</li>
5023
5024 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5025 being invoked. The argument types must match the types implied by this
5026 signature. This type can be omitted if the function is not varargs and if
5027 the function type does not return a pointer to a function.</li>
5028
5029 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5030 be invoked. In most cases, this is a direct function invocation, but
5031 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5032 to function value.</li>
5033
5034 <li>'<tt>function args</tt>': argument list whose types match the function
5035 signature argument types. All arguments must be of
5036 <a href="#t_firstclass">first class</a> type. If the function signature
5037 indicates the function accepts a variable number of arguments, the extra
5038 arguments can be specified.</li>
5039
5040 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5041 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5042 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5043</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5044
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5045<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5046<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5047 a specified function, with its incoming arguments bound to the specified
5048 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5049 function, control flow continues with the instruction after the function
5050 call, and the return value of the function is bound to the result
5051 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5052
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5053<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5054<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5055 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5056 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5057 %X = tail call i32 @foo() <i>; yields i32</i>
5058 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5059 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5060
5061 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5062 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5063 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5064 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5065 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5066 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5067</pre>
5068
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5069<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5070standard C99 library as being the C99 library functions, and may perform
5071optimizations or generate code for them under that assumption. This is
5072something we'd like to change in the future to provide better support for
5073freestanding environments and non-C-based langauges.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5074
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5075</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5076
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5077<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5078<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5079 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5080</div>
5081
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5082<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5083
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5084<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5085<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5086 &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]5087</pre>
5088
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5089<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5090<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5091 the "variable argument" area of a function call. It is used to implement the
5092 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5093
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5094<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5095<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5096 argument. It returns a value of the specified argument type and increments
5097 the <tt>va_list</tt> to point to the next argument. The actual type
5098 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5099
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5100<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5101<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5102 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5103 to the next argument. For more information, see the variable argument
5104 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5105
5106<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]5107 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5108 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5109
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5110<p><tt>va_arg</tt> is an LLVM instruction instead of
5111 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5112 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5113
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5114<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5115<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5116
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5117<p>Note that the code generator does not yet fully support va_arg on many
5118 targets. Also, it does not currently support va_arg with aggregate types on
5119 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5120
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5121</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5122
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5123<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5124<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5125<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5126
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5127<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5128
5129<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5130 well known names and semantics and are required to follow certain
5131 restrictions. Overall, these intrinsics represent an extension mechanism for
5132 the LLVM language that does not require changing all of the transformations
5133 in LLVM when adding to the language (or the bitcode reader/writer, the
5134 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5135
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5136<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5137 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5138 begin with this prefix. Intrinsic functions must always be external
5139 functions: you cannot define the body of intrinsic functions. Intrinsic
5140 functions may only be used in call or invoke instructions: it is illegal to
5141 take the address of an intrinsic function. Additionally, because intrinsic
5142 functions are part of the LLVM language, it is required if any are added that
5143 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5144
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5145<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5146 family of functions that perform the same operation but on different data
5147 types. Because LLVM can represent over 8 million different integer types,
5148 overloading is used commonly to allow an intrinsic function to operate on any
5149 integer type. One or more of the argument types or the result type can be
5150 overloaded to accept any integer type. Argument types may also be defined as
5151 exactly matching a previous argument's type or the result type. This allows
5152 an intrinsic function which accepts multiple arguments, but needs all of them
5153 to be of the same type, to only be overloaded with respect to a single
5154 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5155
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5156<p>Overloaded intrinsics will have the names of its overloaded argument types
5157 encoded into its function name, each preceded by a period. Only those types
5158 which are overloaded result in a name suffix. Arguments whose type is matched
5159 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5160 can take an integer of any width and returns an integer of exactly the same
5161 integer width. This leads to a family of functions such as
5162 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5163 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5164 suffix is required. Because the argument's type is matched against the return
5165 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5166
5167<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5168 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5169
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5170</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5171
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5172<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5173<div class="doc_subsection">
5174 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5175</div>
5176
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5177<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5178
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5179<p>Variable argument support is defined in LLVM with
5180 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5181 intrinsic functions. These functions are related to the similarly named
5182 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5183
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5184<p>All of these functions operate on arguments that use a target-specific value
5185 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5186 not define what this type is, so all transformations should be prepared to
5187 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5188
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5189<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]5190 instruction and the variable argument handling intrinsic functions are
5191 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5192
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5193<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5194<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5195define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5196 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5197 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5198 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5199 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5200
5201 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5202 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5203
5204 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5205 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5206 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5207 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5208 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5209
5210 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5211 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5212 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5213}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5214
5215declare void @llvm.va_start(i8*)
5216declare void @llvm.va_copy(i8*, i8*)
5217declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5218</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5219</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5220
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5221</div>
5222
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5223<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5224<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5225 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5226</div>
5227
5228
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5229<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5230
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5231<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5232<pre>
5233 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5234</pre>
5235
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5236<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5237<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5238 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]5239
5240<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5241<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]5242
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5243<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5244<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]5245 macro available in C. In a target-dependent way, it initializes
5246 the <tt>va_list</tt> element to which the argument points, so that the next
5247 call to <tt>va_arg</tt> will produce the first variable argument passed to
5248 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5249 need to know the last argument of the function as the compiler can figure
5250 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5251
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5252</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5253
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5254<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5255<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5256 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5257</div>
5258
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5259<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5260
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5261<h5>Syntax:</h5>
5262<pre>
5263 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5264</pre>
5265
5266<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5267<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5268 which has been initialized previously
5269 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5270 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5271
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5272<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5273<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]5274
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5275<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5276<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]5277 macro available in C. In a target-dependent way, it destroys
5278 the <tt>va_list</tt> element to which the argument points. Calls
5279 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5280 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5281 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5282
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5283</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5284
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5285<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5286<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5287 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5288</div>
5289
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5290<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5291
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5292<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5293<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5294 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5295</pre>
5296
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5297<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5298<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5299 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5300
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5301<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5302<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]5303 The second argument is a pointer to a <tt>va_list</tt> element to copy
5304 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5305
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5306<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5307<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]5308 macro available in C. In a target-dependent way, it copies the
5309 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5310 element. This intrinsic is necessary because
5311 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5312 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5313
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5314</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5315
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5316<!-- ======================================================================= -->
5317<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5318 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5319</div>
5320
5321<div class="doc_text">
5322
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5323<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5324Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5325intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5326roots on the stack</a>, as well as garbage collector implementations that
5327require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5328barriers. Front-ends for type-safe garbage collected languages should generate
5329these intrinsics to make use of the LLVM garbage collectors. For more details,
5330see <a href="GarbageCollection.html">Accurate Garbage Collection with
5331LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5332
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5333<p>The garbage collection intrinsics only operate on objects in the generic
5334 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5335
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5336</div>
5337
5338<!-- _______________________________________________________________________ -->
5339<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5340 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5341</div>
5342
5343<div class="doc_text">
5344
5345<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5346<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5347 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5348</pre>
5349
5350<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5351<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]5352 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5353
5354<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5355<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5356 root pointer. The second pointer (which must be either a constant or a
5357 global value address) contains the meta-data to be associated with the
5358 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5359
5360<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5361<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]5362 location. At compile-time, the code generator generates information to allow
5363 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5364 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5365 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5366
5367</div>
5368
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5369<!-- _______________________________________________________________________ -->
5370<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5371 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5372</div>
5373
5374<div class="doc_text">
5375
5376<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5377<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5378 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5379</pre>
5380
5381<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5382<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5383 locations, allowing garbage collector implementations that require read
5384 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5385
5386<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5387<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]5388 allocated from the garbage collector. The first object is a pointer to the
5389 start of the referenced object, if needed by the language runtime (otherwise
5390 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5391
5392<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5393<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5394 instruction, but may be replaced with substantially more complex code by the
5395 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5396 may only be used in a function which <a href="#gc">specifies a GC
5397 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5398
5399</div>
5400
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5401<!-- _______________________________________________________________________ -->
5402<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5403 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5404</div>
5405
5406<div class="doc_text">
5407
5408<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5409<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5410 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5411</pre>
5412
5413<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5414<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5415 locations, allowing garbage collector implementations that require write
5416 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5417
5418<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5419<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]5420 object to store it to, and the third is the address of the field of Obj to
5421 store to. If the runtime does not require a pointer to the object, Obj may
5422 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5423
5424<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5425<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5426 instruction, but may be replaced with substantially more complex code by the
5427 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5428 may only be used in a function which <a href="#gc">specifies a GC
5429 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5430
5431</div>
5432
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5433<!-- ======================================================================= -->
5434<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5435 <a name="int_codegen">Code Generator Intrinsics</a>
5436</div>
5437
5438<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5439
5440<p>These intrinsics are provided by LLVM to expose special features that may
5441 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5442
5443</div>
5444
5445<!-- _______________________________________________________________________ -->
5446<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5447 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5448</div>
5449
5450<div class="doc_text">
5451
5452<h5>Syntax:</h5>
5453<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5454 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5455</pre>
5456
5457<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5458<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5459 target-specific value indicating the return address of the current function
5460 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5461
5462<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5463<p>The argument to this intrinsic indicates which function to return the address
5464 for. Zero indicates the calling function, one indicates its caller, etc.
5465 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5466
5467<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5468<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5469 indicating the return address of the specified call frame, or zero if it
5470 cannot be identified. The value returned by this intrinsic is likely to be
5471 incorrect or 0 for arguments other than zero, so it should only be used for
5472 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5473
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5474<p>Note that calling this intrinsic does not prevent function inlining or other
5475 aggressive transformations, so the value returned may not be that of the
5476 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5477
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5478</div>
5479
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5480<!-- _______________________________________________________________________ -->
5481<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5482 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5483</div>
5484
5485<div class="doc_text">
5486
5487<h5>Syntax:</h5>
5488<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5489 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5490</pre>
5491
5492<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5493<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5494 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5495
5496<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5497<p>The argument to this intrinsic indicates which function to return the frame
5498 pointer for. Zero indicates the calling function, one indicates its caller,
5499 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5500
5501<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5502<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5503 indicating the frame address of the specified call frame, or zero if it
5504 cannot be identified. The value returned by this intrinsic is likely to be
5505 incorrect or 0 for arguments other than zero, so it should only be used for
5506 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5507
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5508<p>Note that calling this intrinsic does not prevent function inlining or other
5509 aggressive transformations, so the value returned may not be that of the
5510 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5511
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5512</div>
5513
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5514<!-- _______________________________________________________________________ -->
5515<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5516 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5517</div>
5518
5519<div class="doc_text">
5520
5521<h5>Syntax:</h5>
5522<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5523 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5524</pre>
5525
5526<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5527<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5528 of the function stack, for use
5529 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5530 useful for implementing language features like scoped automatic variable
5531 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5532
5533<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5534<p>This intrinsic returns a opaque pointer value that can be passed
5535 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5536 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5537 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5538 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5539 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5540 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5541
5542</div>
5543
5544<!-- _______________________________________________________________________ -->
5545<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5546 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5547</div>
5548
5549<div class="doc_text">
5550
5551<h5>Syntax:</h5>
5552<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5553 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5554</pre>
5555
5556<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5557<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5558 the function stack to the state it was in when the
5559 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5560 executed. This is useful for implementing language features like scoped
5561 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5562
5563<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5564<p>See the description
5565 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5566
5567</div>
5568
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5569<!-- _______________________________________________________________________ -->
5570<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5571 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5572</div>
5573
5574<div class="doc_text">
5575
5576<h5>Syntax:</h5>
5577<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5578 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]5579</pre>
5580
5581<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5582<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5583 insert a prefetch instruction if supported; otherwise, it is a noop.
5584 Prefetches have no effect on the behavior of the program but can change its
5585 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5586
5587<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5588<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5589 specifier determining if the fetch should be for a read (0) or write (1),
5590 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5591 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5592 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5593
5594<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5595<p>This intrinsic does not modify the behavior of the program. In particular,
5596 prefetches cannot trap and do not produce a value. On targets that support
5597 this intrinsic, the prefetch can provide hints to the processor cache for
5598 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5599
5600</div>
5601
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5602<!-- _______________________________________________________________________ -->
5603<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5604 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5605</div>
5606
5607<div class="doc_text">
5608
5609<h5>Syntax:</h5>
5610<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5611 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5612</pre>
5613
5614<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5615<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5616 Counter (PC) in a region of code to simulators and other tools. The method
5617 is target specific, but it is expected that the marker will use exported
5618 symbols to transmit the PC of the marker. The marker makes no guarantees
5619 that it will remain with any specific instruction after optimizations. It is
5620 possible that the presence of a marker will inhibit optimizations. The
5621 intended use is to be inserted after optimizations to allow correlations of
5622 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5623
5624<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5625<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5626
5627<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5628<p>This intrinsic does not modify the behavior of the program. Backends that do
5629 not support this intrinisic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5630
5631</div>
5632
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5633<!-- _______________________________________________________________________ -->
5634<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5635 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5636</div>
5637
5638<div class="doc_text">
5639
5640<h5>Syntax:</h5>
5641<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5642 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5643</pre>
5644
5645<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5646<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5647 counter register (or similar low latency, high accuracy clocks) on those
5648 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5649 should map to RPCC. As the backing counters overflow quickly (on the order
5650 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5651
5652<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5653<p>When directly supported, reading the cycle counter should not modify any
5654 memory. Implementations are allowed to either return a application specific
5655 value or a system wide value. On backends without support, this is lowered
5656 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5657
5658</div>
5659
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5660<!-- ======================================================================= -->
5661<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5662 <a name="int_libc">Standard C Library Intrinsics</a>
5663</div>
5664
5665<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5666
5667<p>LLVM provides intrinsics for a few important standard C library functions.
5668 These intrinsics allow source-language front-ends to pass information about
5669 the alignment of the pointer arguments to the code generator, providing
5670 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5671
5672</div>
5673
5674<!-- _______________________________________________________________________ -->
5675<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5676 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5677</div>
5678
5679<div class="doc_text">
5680
5681<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5682<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5683 integer bit width. Not all targets support all bit widths however.</p>
5684
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5685<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5686 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5687 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5688 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5689 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5690 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5691 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5692 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5693 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5694</pre>
5695
5696<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5697<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5698 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5699
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5700<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5701 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5702
5703<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5704<p>The first argument is a pointer to the destination, the second is a pointer
5705 to the source. The third argument is an integer argument specifying the
5706 number of bytes to copy, and the fourth argument is the alignment of the
5707 source and destination locations.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5708
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5709<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5710 then the caller guarantees that both the source and destination pointers are
5711 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5712
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5713<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5714<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5715 source location to the destination location, which are not allowed to
5716 overlap. It copies "len" bytes of memory over. If the argument is known to
5717 be aligned to some boundary, this can be specified as the fourth argument,
5718 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5719
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5720</div>
5721
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5722<!-- _______________________________________________________________________ -->
5723<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5724 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5725</div>
5726
5727<div class="doc_text">
5728
5729<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5730<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]5731 width. Not all targets support all bit widths however.</p>
5732
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5733<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5734 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5735 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5736 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5737 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5738 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5739 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5740 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5741 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5742</pre>
5743
5744<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5745<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5746 source location to the destination location. It is similar to the
5747 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5748 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5749
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5750<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5751 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5752
5753<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5754<p>The first argument is a pointer to the destination, the second is a pointer
5755 to the source. The third argument is an integer argument specifying the
5756 number of bytes to copy, and the fourth argument is the alignment of the
5757 source and destination locations.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5758
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5759<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5760 then the caller guarantees that the source and destination pointers are
5761 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5762
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5763<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5764<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5765 source location to the destination location, which may overlap. It copies
5766 "len" bytes of memory over. If the argument is known to be aligned to some
5767 boundary, this can be specified as the fourth argument, otherwise it should
5768 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5769
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5770</div>
5771
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5772<!-- _______________________________________________________________________ -->
5773<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5774 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5775</div>
5776
5777<div class="doc_text">
5778
5779<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5780<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]5781 width. Not all targets support all bit widths however.</p>
5782
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5783<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5784 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5785 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5786 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5787 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5788 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5789 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5790 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5791 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5792</pre>
5793
5794<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5795<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5796 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5797
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5798<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5799 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5800
5801<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5802<p>The first argument is a pointer to the destination to fill, the second is the
5803 byte value to fill it with, the third argument is an integer argument
5804 specifying the number of bytes to fill, and the fourth argument is the known
5805 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5806
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5807<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5808 then the caller guarantees that the destination pointer is aligned to that
5809 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5810
5811<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5812<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5813 at the destination location. If the argument is known to be aligned to some
5814 boundary, this can be specified as the fourth argument, otherwise it should
5815 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5816
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5817</div>
5818
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5819<!-- _______________________________________________________________________ -->
5820<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5821 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5822</div>
5823
5824<div class="doc_text">
5825
5826<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5827<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5828 floating point or vector of floating point type. Not all targets support all
5829 types however.</p>
5830
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5831<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5832 declare float @llvm.sqrt.f32(float %Val)
5833 declare double @llvm.sqrt.f64(double %Val)
5834 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5835 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5836 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5837</pre>
5838
5839<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5840<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5841 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5842 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5843 behavior for negative numbers other than -0.0 (which allows for better
5844 optimization, because there is no need to worry about errno being
5845 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]5846
5847<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5848<p>The argument and return value are floating point numbers of the same
5849 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5850
5851<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5852<p>This function returns the sqrt of the specified operand if it is a
5853 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5854
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5855</div>
5856
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5857<!-- _______________________________________________________________________ -->
5858<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5859 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5860</div>
5861
5862<div class="doc_text">
5863
5864<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5865<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5866 floating point or vector of floating point type. Not all targets support all
5867 types however.</p>
5868
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5869<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5870 declare float @llvm.powi.f32(float %Val, i32 %power)
5871 declare double @llvm.powi.f64(double %Val, i32 %power)
5872 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5873 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5874 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5875</pre>
5876
5877<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5878<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5879 specified (positive or negative) power. The order of evaluation of
5880 multiplications is not defined. When a vector of floating point type is
5881 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5882
5883<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5884<p>The second argument is an integer power, and the first is a value to raise to
5885 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5886
5887<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5888<p>This function returns the first value raised to the second power with an
5889 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5890
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5891</div>
5892
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5893<!-- _______________________________________________________________________ -->
5894<div class="doc_subsubsection">
5895 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5896</div>
5897
5898<div class="doc_text">
5899
5900<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5901<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5902 floating point or vector of floating point type. Not all targets support all
5903 types however.</p>
5904
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5905<pre>
5906 declare float @llvm.sin.f32(float %Val)
5907 declare double @llvm.sin.f64(double %Val)
5908 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5909 declare fp128 @llvm.sin.f128(fp128 %Val)
5910 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5911</pre>
5912
5913<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5914<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5915
5916<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5917<p>The argument and return value are floating point numbers of the same
5918 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5919
5920<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5921<p>This function returns the sine of the specified operand, returning the same
5922 values as the libm <tt>sin</tt> functions would, and handles error conditions
5923 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5924
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5925</div>
5926
5927<!-- _______________________________________________________________________ -->
5928<div class="doc_subsubsection">
5929 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5930</div>
5931
5932<div class="doc_text">
5933
5934<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5935<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5936 floating point or vector of floating point type. Not all targets support all
5937 types however.</p>
5938
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5939<pre>
5940 declare float @llvm.cos.f32(float %Val)
5941 declare double @llvm.cos.f64(double %Val)
5942 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5943 declare fp128 @llvm.cos.f128(fp128 %Val)
5944 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5945</pre>
5946
5947<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5948<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5949
5950<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5951<p>The argument and return value are floating point numbers of the same
5952 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5953
5954<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5955<p>This function returns the cosine of the specified operand, returning the same
5956 values as the libm <tt>cos</tt> functions would, and handles error conditions
5957 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5958
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5959</div>
5960
5961<!-- _______________________________________________________________________ -->
5962<div class="doc_subsubsection">
5963 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5964</div>
5965
5966<div class="doc_text">
5967
5968<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5969<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5970 floating point or vector of floating point type. Not all targets support all
5971 types however.</p>
5972
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5973<pre>
5974 declare float @llvm.pow.f32(float %Val, float %Power)
5975 declare double @llvm.pow.f64(double %Val, double %Power)
5976 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5977 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5978 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5979</pre>
5980
5981<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5982<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5983 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5984
5985<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5986<p>The second argument is a floating point power, and the first is a value to
5987 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5988
5989<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5990<p>This function returns the first value raised to the second power, returning
5991 the same values as the libm <tt>pow</tt> functions would, and handles error
5992 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5993
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5994</div>
5995
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5996<!-- ======================================================================= -->
5997<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5998 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5999</div>
6000
6001<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6002
6003<p>LLVM provides intrinsics for a few important bit manipulation operations.
6004 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6005
6006</div>
6007
6008<!-- _______________________________________________________________________ -->
6009<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6010 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6011</div>
6012
6013<div class="doc_text">
6014
6015<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6016<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6017 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6018
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6019<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6020 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6021 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6022 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6023</pre>
6024
6025<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6026<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6027 values with an even number of bytes (positive multiple of 16 bits). These
6028 are useful for performing operations on data that is not in the target's
6029 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6030
6031<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6032<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6033 and low byte of the input i16 swapped. Similarly,
6034 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6035 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6036 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6037 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6038 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6039 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6040
6041</div>
6042
6043<!-- _______________________________________________________________________ -->
6044<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6045 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6046</div>
6047
6048<div class="doc_text">
6049
6050<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6051<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]6052 width. Not all targets support all bit widths however.</p>
6053
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6054<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6055 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6056 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6057 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6058 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6059 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6060</pre>
6061
6062<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6063<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6064 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6065
6066<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6067<p>The only argument is the value to be counted. The argument may be of any
6068 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6069
6070<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6071<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]6072
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6073</div>
6074
6075<!-- _______________________________________________________________________ -->
6076<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6077 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6078</div>
6079
6080<div class="doc_text">
6081
6082<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6083<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6084 integer bit width. Not all targets support all bit widths however.</p>
6085
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6086<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6087 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6088 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6089 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6090 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6091 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6092</pre>
6093
6094<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6095<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6096 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6097
6098<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6099<p>The only argument is the value to be counted. The argument may be of any
6100 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6101
6102<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6103<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6104 zeros in a variable. If the src == 0 then the result is the size in bits of
6105 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6106
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6107</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6108
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6109<!-- _______________________________________________________________________ -->
6110<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6111 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6112</div>
6113
6114<div class="doc_text">
6115
6116<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6117<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6118 integer bit width. Not all targets support all bit widths however.</p>
6119
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6120<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6121 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6122 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6123 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6124 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6125 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6126</pre>
6127
6128<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6129<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6130 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6131
6132<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6133<p>The only argument is the value to be counted. The argument may be of any
6134 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6135
6136<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6137<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6138 zeros in a variable. If the src == 0 then the result is the size in bits of
6139 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6140
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6141</div>
6142
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6143<!-- ======================================================================= -->
6144<div class="doc_subsection">
6145 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6146</div>
6147
6148<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6149
6150<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6151
6152</div>
6153
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6154<!-- _______________________________________________________________________ -->
6155<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6156 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6157</div>
6158
6159<div class="doc_text">
6160
6161<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6162<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]6163 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6164
6165<pre>
6166 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6167 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6168 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6169</pre>
6170
6171<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6172<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6173 a signed addition of the two arguments, and indicate whether an overflow
6174 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6175
6176<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6177<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]6178 be of integer types of any bit width, but they must have the same bit
6179 width. The second element of the result structure must be of
6180 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6181 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6182
6183<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6184<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6185 a signed addition of the two variables. They return a structure &mdash; the
6186 first element of which is the signed summation, and the second element of
6187 which is a bit specifying if the signed summation resulted in an
6188 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6189
6190<h5>Examples:</h5>
6191<pre>
6192 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6193 %sum = extractvalue {i32, i1} %res, 0
6194 %obit = extractvalue {i32, i1} %res, 1
6195 br i1 %obit, label %overflow, label %normal
6196</pre>
6197
6198</div>
6199
6200<!-- _______________________________________________________________________ -->
6201<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6202 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6203</div>
6204
6205<div class="doc_text">
6206
6207<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6208<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]6209 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6210
6211<pre>
6212 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6213 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6214 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6215</pre>
6216
6217<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6218<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6219 an unsigned addition of the two arguments, and indicate whether a carry
6220 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6221
6222<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6223<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]6224 be of integer types of any bit width, but they must have the same bit
6225 width. The second element of the result structure must be of
6226 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6227 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6228
6229<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6230<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6231 an unsigned addition of the two arguments. They return a structure &mdash;
6232 the first element of which is the sum, and the second element of which is a
6233 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6234
6235<h5>Examples:</h5>
6236<pre>
6237 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6238 %sum = extractvalue {i32, i1} %res, 0
6239 %obit = extractvalue {i32, i1} %res, 1
6240 br i1 %obit, label %carry, label %normal
6241</pre>
6242
6243</div>
6244
6245<!-- _______________________________________________________________________ -->
6246<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6247 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6248</div>
6249
6250<div class="doc_text">
6251
6252<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6253<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]6254 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6255
6256<pre>
6257 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6258 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6259 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6260</pre>
6261
6262<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6263<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6264 a signed subtraction of the two arguments, and indicate whether an overflow
6265 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6266
6267<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6268<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]6269 be of integer types of any bit width, but they must have the same bit
6270 width. The second element of the result structure must be of
6271 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6272 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6273
6274<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6275<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6276 a signed subtraction of the two arguments. They return a structure &mdash;
6277 the first element of which is the subtraction, and the second element of
6278 which is a bit specifying if the signed subtraction resulted in an
6279 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6280
6281<h5>Examples:</h5>
6282<pre>
6283 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6284 %sum = extractvalue {i32, i1} %res, 0
6285 %obit = extractvalue {i32, i1} %res, 1
6286 br i1 %obit, label %overflow, label %normal
6287</pre>
6288
6289</div>
6290
6291<!-- _______________________________________________________________________ -->
6292<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6293 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6294</div>
6295
6296<div class="doc_text">
6297
6298<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6299<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]6300 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6301
6302<pre>
6303 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6304 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6305 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6306</pre>
6307
6308<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6309<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6310 an unsigned subtraction of the two arguments, and indicate whether an
6311 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6312
6313<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6314<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]6315 be of integer types of any bit width, but they must have the same bit
6316 width. The second element of the result structure must be of
6317 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6318 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6319
6320<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6321<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6322 an unsigned subtraction of the two arguments. They return a structure &mdash;
6323 the first element of which is the subtraction, and the second element of
6324 which is a bit specifying if the unsigned subtraction resulted in an
6325 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6326
6327<h5>Examples:</h5>
6328<pre>
6329 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6330 %sum = extractvalue {i32, i1} %res, 0
6331 %obit = extractvalue {i32, i1} %res, 1
6332 br i1 %obit, label %overflow, label %normal
6333</pre>
6334
6335</div>
6336
6337<!-- _______________________________________________________________________ -->
6338<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6339 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6340</div>
6341
6342<div class="doc_text">
6343
6344<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6345<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]6346 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6347
6348<pre>
6349 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6350 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6351 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6352</pre>
6353
6354<h5>Overview:</h5>
6355
6356<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6357 a signed multiplication of the two arguments, and indicate whether an
6358 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6359
6360<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6361<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]6362 be of integer types of any bit width, but they must have the same bit
6363 width. The second element of the result structure must be of
6364 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6365 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6366
6367<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6368<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6369 a signed multiplication of the two arguments. They return a structure &mdash;
6370 the first element of which is the multiplication, and the second element of
6371 which is a bit specifying if the signed multiplication resulted in an
6372 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6373
6374<h5>Examples:</h5>
6375<pre>
6376 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6377 %sum = extractvalue {i32, i1} %res, 0
6378 %obit = extractvalue {i32, i1} %res, 1
6379 br i1 %obit, label %overflow, label %normal
6380</pre>
6381
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6382</div>
6383
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6384<!-- _______________________________________________________________________ -->
6385<div class="doc_subsubsection">
6386 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6387</div>
6388
6389<div class="doc_text">
6390
6391<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6392<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]6393 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6394
6395<pre>
6396 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6397 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6398 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6399</pre>
6400
6401<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6402<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6403 a unsigned multiplication of the two arguments, and indicate whether an
6404 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6405
6406<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6407<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]6408 be of integer types of any bit width, but they must have the same bit
6409 width. The second element of the result structure must be of
6410 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6411 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6412
6413<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6414<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6415 an unsigned multiplication of the two arguments. They return a structure
6416 &mdash; the first element of which is the multiplication, and the second
6417 element of which is a bit specifying if the unsigned multiplication resulted
6418 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6419
6420<h5>Examples:</h5>
6421<pre>
6422 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6423 %sum = extractvalue {i32, i1} %res, 0
6424 %obit = extractvalue {i32, i1} %res, 1
6425 br i1 %obit, label %overflow, label %normal
6426</pre>
6427
6428</div>
6429
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6430<!-- ======================================================================= -->
6431<div class="doc_subsection">
6432 <a name="int_debugger">Debugger Intrinsics</a>
6433</div>
6434
6435<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6436
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6437<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6438 prefix), are described in
6439 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6440 Level Debugging</a> document.</p>
6441
6442</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6443
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6444<!-- ======================================================================= -->
6445<div class="doc_subsection">
6446 <a name="int_eh">Exception Handling Intrinsics</a>
6447</div>
6448
6449<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6450
6451<p>The LLVM exception handling intrinsics (which all start with
6452 <tt>llvm.eh.</tt> prefix), are described in
6453 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6454 Handling</a> document.</p>
6455
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6456</div>
6457
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6458<!-- ======================================================================= -->
6459<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6460 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6461</div>
6462
6463<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6464
6465<p>This intrinsic makes it possible to excise one parameter, marked with
6466 the <tt>nest</tt> attribute, from a function. The result is a callable
6467 function pointer lacking the nest parameter - the caller does not need to
6468 provide a value for it. Instead, the value to use is stored in advance in a
6469 "trampoline", a block of memory usually allocated on the stack, which also
6470 contains code to splice the nest value into the argument list. This is used
6471 to implement the GCC nested function address extension.</p>
6472
6473<p>For example, if the function is
6474 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6475 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6476 follows:</p>
6477
6478<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6479<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6480 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6481 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6482 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6483 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6484</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6485</div>
6486
6487<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6488 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6489
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6490</div>
6491
6492<!-- _______________________________________________________________________ -->
6493<div class="doc_subsubsection">
6494 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6495</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6496
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6497<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6498
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6499<h5>Syntax:</h5>
6500<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6501 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]6502</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6503
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6504<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6505<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6506 function pointer suitable for executing it.</p>
6507
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6508<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6509<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6510 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6511 sufficiently aligned block of memory; this memory is written to by the
6512 intrinsic. Note that the size and the alignment are target-specific - LLVM
6513 currently provides no portable way of determining them, so a front-end that
6514 generates this intrinsic needs to have some target-specific knowledge.
6515 The <tt>func</tt> argument must hold a function bitcast to
6516 an <tt>i8*</tt>.</p>
6517
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6518<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6519<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6520 dependent code, turning it into a function. A pointer to this function is
6521 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6522 function pointer type</a> before being called. The new function's signature
6523 is the same as that of <tt>func</tt> with any arguments marked with
6524 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6525 is allowed, and it must be of pointer type. Calling the new function is
6526 equivalent to calling <tt>func</tt> with the same argument list, but
6527 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6528 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6529 by <tt>tramp</tt> is modified, then the effect of any later call to the
6530 returned function pointer is undefined.</p>
6531
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6532</div>
6533
6534<!-- ======================================================================= -->
6535<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6536 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6537</div>
6538
6539<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6540
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6541<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6542 hardware constructs for atomic operations and memory synchronization. This
6543 provides an interface to the hardware, not an interface to the programmer. It
6544 is aimed at a low enough level to allow any programming models or APIs
6545 (Application Programming Interfaces) which need atomic behaviors to map
6546 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6547 hardware provides a "universal IR" for source languages, it also provides a
6548 starting point for developing a "universal" atomic operation and
6549 synchronization IR.</p>
6550
6551<p>These do <em>not</em> form an API such as high-level threading libraries,
6552 software transaction memory systems, atomic primitives, and intrinsic
6553 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6554 application libraries. The hardware interface provided by LLVM should allow
6555 a clean implementation of all of these APIs and parallel programming models.
6556 No one model or paradigm should be selected above others unless the hardware
6557 itself ubiquitously does so.</p>
6558
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6559</div>
6560
6561<!-- _______________________________________________________________________ -->
6562<div class="doc_subsubsection">
6563 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6564</div>
6565<div class="doc_text">
6566<h5>Syntax:</h5>
6567<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6568 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]6569</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6570
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6571<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6572<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6573 specific pairs of memory access types.</p>
6574
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6575<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6576<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6577 The first four arguments enables a specific barrier as listed below. The
6578 fith argument specifies that the barrier applies to io or device or uncached
6579 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6580
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6581<ul>
6582 <li><tt>ll</tt>: load-load barrier</li>
6583 <li><tt>ls</tt>: load-store barrier</li>
6584 <li><tt>sl</tt>: store-load barrier</li>
6585 <li><tt>ss</tt>: store-store barrier</li>
6586 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6587</ul>
6588
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6589<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6590<p>This intrinsic causes the system to enforce some ordering constraints upon
6591 the loads and stores of the program. This barrier does not
6592 indicate <em>when</em> any events will occur, it only enforces
6593 an <em>order</em> in which they occur. For any of the specified pairs of load
6594 and store operations (f.ex. load-load, or store-load), all of the first
6595 operations preceding the barrier will complete before any of the second
6596 operations succeeding the barrier begin. Specifically the semantics for each
6597 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6598
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6599<ul>
6600 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6601 after the barrier begins.</li>
6602 <li><tt>ls</tt>: All loads before the barrier must complete before any
6603 store after the barrier begins.</li>
6604 <li><tt>ss</tt>: All stores before the barrier must complete before any
6605 store after the barrier begins.</li>
6606 <li><tt>sl</tt>: All stores before the barrier must complete before any
6607 load after the barrier begins.</li>
6608</ul>
6609
6610<p>These semantics are applied with a logical "and" behavior when more than one
6611 is enabled in a single memory barrier intrinsic.</p>
6612
6613<p>Backends may implement stronger barriers than those requested when they do
6614 not support as fine grained a barrier as requested. Some architectures do
6615 not need all types of barriers and on such architectures, these become
6616 noops.</p>
6617
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6618<h5>Example:</h5>
6619<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6620%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6621%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6622 store i32 4, %ptr
6623
6624%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6625 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6626 <i>; guarantee the above finishes</i>
6627 store i32 8, %ptr <i>; before this begins</i>
6628</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6629
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6630</div>
6631
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6632<!-- _______________________________________________________________________ -->
6633<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6634 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6635</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6636
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6637<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6638
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6639<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6640<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6641 any integer bit width and for different address spaces. Not all targets
6642 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6643
6644<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6645 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6646 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6647 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6648 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]6649</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6650
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6651<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6652<p>This loads a value in memory and compares it to a given value. If they are
6653 equal, it stores a new value into the memory.</p>
6654
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6655<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6656<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6657 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6658 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6659 this integer type. While any bit width integer may be used, targets may only
6660 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6661
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6662<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6663<p>This entire intrinsic must be executed atomically. It first loads the value
6664 in memory pointed to by <tt>ptr</tt> and compares it with the
6665 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6666 memory. The loaded value is yielded in all cases. This provides the
6667 equivalent of an atomic compare-and-swap operation within the SSA
6668 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6669
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6670<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6671<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6672%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6673%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6674 store i32 4, %ptr
6675
6676%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6677%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6678 <i>; yields {i32}:result1 = 4</i>
6679%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6680%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6681
6682%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6683%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6684 <i>; yields {i32}:result2 = 8</i>
6685%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6686
6687%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6688</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6689
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6690</div>
6691
6692<!-- _______________________________________________________________________ -->
6693<div class="doc_subsubsection">
6694 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6695</div>
6696<div class="doc_text">
6697<h5>Syntax:</h5>
6698
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6699<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6700 integer bit width. Not all targets support all bit widths however.</p>
6701
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6702<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6703 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6704 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6705 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6706 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]6707</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6708
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6709<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6710<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6711 the value from memory. It then stores the value in <tt>val</tt> in the memory
6712 at <tt>ptr</tt>.</p>
6713
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6714<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6715<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6716 the <tt>val</tt> argument and the result must be integers of the same bit
6717 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6718 integer type. The targets may only lower integer representations they
6719 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6720
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6721<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6722<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6723 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6724 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6725
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6726<h5>Examples:</h5>
6727<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6728%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6729%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6730 store i32 4, %ptr
6731
6732%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6733%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6734 <i>; yields {i32}:result1 = 4</i>
6735%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6736%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6737
6738%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6739%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6740 <i>; yields {i32}:result2 = 8</i>
6741
6742%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6743%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6744</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6745
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6746</div>
6747
6748<!-- _______________________________________________________________________ -->
6749<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6750 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6751
6752</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6753
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6754<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6755
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6756<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6757<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6758 any integer bit width. Not all targets support all bit widths however.</p>
6759
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6760<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6761 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6762 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6763 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6764 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]6765</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6766
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6767<h5>Overview:</h5>
6768<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6769 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6770
6771<h5>Arguments:</h5>
6772<p>The intrinsic takes two arguments, the first a pointer to an integer value
6773 and the second an integer value. The result is also an integer value. These
6774 integer types can have any bit width, but they must all have the same bit
6775 width. The targets may only lower integer representations they support.</p>
6776
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6777<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6778<p>This intrinsic does a series of operations atomically. It first loads the
6779 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6780 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]6781
6782<h5>Examples:</h5>
6783<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6784%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6785%ptr = bitcast i8* %mallocP to i32*
6786 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6787%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6788 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6789%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6790 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6791%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6792 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6793%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6794</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6795
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6796</div>
6797
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6798<!-- _______________________________________________________________________ -->
6799<div class="doc_subsubsection">
6800 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6801
6802</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6803
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6804<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6805
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6806<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6807<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6808 any integer bit width and for different address spaces. Not all targets
6809 support all bit widths however.</p>
6810
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6811<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6812 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6813 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6814 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6815 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]6816</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6817
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6818<h5>Overview:</h5>
6819<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6820 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6821
6822<h5>Arguments:</h5>
6823<p>The intrinsic takes two arguments, the first a pointer to an integer value
6824 and the second an integer value. The result is also an integer value. These
6825 integer types can have any bit width, but they must all have the same bit
6826 width. The targets may only lower integer representations they support.</p>
6827
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6828<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6829<p>This intrinsic does a series of operations atomically. It first loads the
6830 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6831 result to <tt>ptr</tt>. It yields the original value stored
6832 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6833
6834<h5>Examples:</h5>
6835<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6836%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6837%ptr = bitcast i8* %mallocP to i32*
6838 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6839%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6840 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6841%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6842 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6843%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6844 <i>; yields {i32}:result3 = 2</i>
6845%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6846</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6847
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6848</div>
6849
6850<!-- _______________________________________________________________________ -->
6851<div class="doc_subsubsection">
6852 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6853 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6854 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6855 <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]6856</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6857
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6858<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6859
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6860<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6861<p>These are overloaded intrinsics. You can
6862 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6863 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6864 bit width and for different address spaces. Not all targets support all bit
6865 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6866
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6867<pre>
6868 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6869 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6870 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6871 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]6872</pre>
6873
6874<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6875 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6876 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6877 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6878 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]6879</pre>
6880
6881<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6882 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6883 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6884 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6885 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]6886</pre>
6887
6888<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6889 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6890 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6891 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6892 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]6893</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6894
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6895<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6896<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6897 the value stored in memory at <tt>ptr</tt>. It yields the original value
6898 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6899
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6900<h5>Arguments:</h5>
6901<p>These intrinsics take two arguments, the first a pointer to an integer value
6902 and the second an integer value. The result is also an integer value. These
6903 integer types can have any bit width, but they must all have the same bit
6904 width. The targets may only lower integer representations they support.</p>
6905
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6906<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6907<p>These intrinsics does a series of operations atomically. They first load the
6908 value stored at <tt>ptr</tt>. They then do the bitwise
6909 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6910 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6911
6912<h5>Examples:</h5>
6913<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6914%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6915%ptr = bitcast i8* %mallocP to i32*
6916 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6917%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6918 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6919%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6920 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6921%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6922 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6923%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6924 <i>; yields {i32}:result3 = FF</i>
6925%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6926</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6927
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6928</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6929
6930<!-- _______________________________________________________________________ -->
6931<div class="doc_subsubsection">
6932 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6933 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6934 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6935 <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]6936</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6937
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6938<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6939
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6940<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6941<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6942 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6943 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6944 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6945
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6946<pre>
6947 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6948 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6949 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6950 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]6951</pre>
6952
6953<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6954 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6955 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6956 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6957 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]6958</pre>
6959
6960<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6961 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6962 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6963 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6964 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]6965</pre>
6966
6967<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6968 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6969 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6970 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6971 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]6972</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6973
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6974<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6975<p>These intrinsics takes the signed or unsigned minimum or maximum of
6976 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6977 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6978
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6979<h5>Arguments:</h5>
6980<p>These intrinsics take two arguments, the first a pointer to an integer value
6981 and the second an integer value. The result is also an integer value. These
6982 integer types can have any bit width, but they must all have the same bit
6983 width. The targets may only lower integer representations they support.</p>
6984
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6985<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6986<p>These intrinsics does a series of operations atomically. They first load the
6987 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6988 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6989 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6990
6991<h5>Examples:</h5>
6992<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6993%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6994%ptr = bitcast i8* %mallocP to i32*
6995 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6996%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6997 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6998%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6999 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7000%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7001 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7002%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7003 <i>; yields {i32}:result3 = 8</i>
7004%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7005</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7006
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7007</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7008
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7009
7010<!-- ======================================================================= -->
7011<div class="doc_subsection">
7012 <a name="int_memorymarkers">Memory Use Markers</a>
7013</div>
7014
7015<div class="doc_text">
7016
7017<p>This class of intrinsics exists to information about the lifetime of memory
7018 objects and ranges where variables are immutable.</p>
7019
7020</div>
7021
7022<!-- _______________________________________________________________________ -->
7023<div class="doc_subsubsection">
7024 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7025</div>
7026
7027<div class="doc_text">
7028
7029<h5>Syntax:</h5>
7030<pre>
7031 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7032</pre>
7033
7034<h5>Overview:</h5>
7035<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7036 object's lifetime.</p>
7037
7038<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7039<p>The first argument is a constant integer representing the size of the
7040 object, or -1 if it is variable sized. The second argument is a pointer to
7041 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7042
7043<h5>Semantics:</h5>
7044<p>This intrinsic indicates that before this point in the code, the value of the
7045 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]7046 never be used and has an undefined value. A load from the pointer that
7047 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7048 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7049
7050</div>
7051
7052<!-- _______________________________________________________________________ -->
7053<div class="doc_subsubsection">
7054 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7055</div>
7056
7057<div class="doc_text">
7058
7059<h5>Syntax:</h5>
7060<pre>
7061 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7062</pre>
7063
7064<h5>Overview:</h5>
7065<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7066 object's lifetime.</p>
7067
7068<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7069<p>The first argument is a constant integer representing the size of the
7070 object, or -1 if it is variable sized. The second argument is a pointer to
7071 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7072
7073<h5>Semantics:</h5>
7074<p>This intrinsic indicates that after this point in the code, the value of the
7075 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7076 never be used and has an undefined value. Any stores into the memory object
7077 following this intrinsic may be removed as dead.
7078
7079</div>
7080
7081<!-- _______________________________________________________________________ -->
7082<div class="doc_subsubsection">
7083 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7084</div>
7085
7086<div class="doc_text">
7087
7088<h5>Syntax:</h5>
7089<pre>
7090 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7091</pre>
7092
7093<h5>Overview:</h5>
7094<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7095 a memory object will not change.</p>
7096
7097<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7098<p>The first argument is a constant integer representing the size of the
7099 object, or -1 if it is variable sized. The second argument is a pointer to
7100 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7101
7102<h5>Semantics:</h5>
7103<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7104 the return value, the referenced memory location is constant and
7105 unchanging.</p>
7106
7107</div>
7108
7109<!-- _______________________________________________________________________ -->
7110<div class="doc_subsubsection">
7111 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7112</div>
7113
7114<div class="doc_text">
7115
7116<h5>Syntax:</h5>
7117<pre>
7118 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7119</pre>
7120
7121<h5>Overview:</h5>
7122<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7123 a memory object are mutable.</p>
7124
7125<h5>Arguments:</h5>
7126<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7127 The second argument is a constant integer representing the size of the
7128 object, or -1 if it is variable sized and the third argument is a pointer
7129 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7130
7131<h5>Semantics:</h5>
7132<p>This intrinsic indicates that the memory is mutable again.</p>
7133
7134</div>
7135
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7136<!-- ======================================================================= -->
7137<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7138 <a name="int_general">General Intrinsics</a>
7139</div>
7140
7141<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7142
7143<p>This class of intrinsics is designed to be generic and has no specific
7144 purpose.</p>
7145
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7146</div>
7147
7148<!-- _______________________________________________________________________ -->
7149<div class="doc_subsubsection">
7150 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7151</div>
7152
7153<div class="doc_text">
7154
7155<h5>Syntax:</h5>
7156<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7157 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]7158</pre>
7159
7160<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7161<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7162
7163<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7164<p>The first argument is a pointer to a value, the second is a pointer to a
7165 global string, the third is a pointer to a global string which is the source
7166 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7167
7168<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7169<p>This intrinsic allows annotation of local variables with arbitrary strings.
7170 This can be useful for special purpose optimizations that want to look for
7171 these annotations. These have no other defined use, they are ignored by code
7172 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7173
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7174</div>
7175
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7176<!-- _______________________________________________________________________ -->
7177<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7178 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7179</div>
7180
7181<div class="doc_text">
7182
7183<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7184<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7185 any integer bit width.</p>
7186
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7187<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7188 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7189 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7190 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7191 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7192 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]7193</pre>
7194
7195<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7196<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7197
7198<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7199<p>The first argument is an integer value (result of some expression), the
7200 second is a pointer to a global string, the third is a pointer to a global
7201 string which is the source file name, and the last argument is the line
7202 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7203
7204<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7205<p>This intrinsic allows annotations to be put on arbitrary expressions with
7206 arbitrary strings. This can be useful for special purpose optimizations that
7207 want to look for these annotations. These have no other defined use, they
7208 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7209
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7210</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7211
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7212<!-- _______________________________________________________________________ -->
7213<div class="doc_subsubsection">
7214 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7215</div>
7216
7217<div class="doc_text">
7218
7219<h5>Syntax:</h5>
7220<pre>
7221 declare void @llvm.trap()
7222</pre>
7223
7224<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7225<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7226
7227<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7228<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7229
7230<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7231<p>This intrinsics is lowered to the target dependent trap instruction. If the
7232 target does not have a trap instruction, this intrinsic will be lowered to
7233 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7234
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7235</div>
7236
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7237<!-- _______________________________________________________________________ -->
7238<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7239 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7240</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7241
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7242<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7243
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7244<h5>Syntax:</h5>
7245<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7246 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7247</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7248
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7249<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7250<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7251 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7252 ensure that it is placed on the stack before local variables.</p>
7253
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7254<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7255<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7256 arguments. The first argument is the value loaded from the stack
7257 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7258 that has enough space to hold the value of the guard.</p>
7259
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7260<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7261<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7262 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7263 stack. This is to ensure that if a local variable on the stack is
7264 overwritten, it will destroy the value of the guard. When the function exits,
7265 the guard on the stack is checked against the original guard. If they're
7266 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7267 function.</p>
7268
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7269</div>
7270
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7271<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7272<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7273<address>
7274 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7275 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7276 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7277 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]7278
7279 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7280 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7281 Last modified: $Date$
7282</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7283
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7284</body>
7285</html>