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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 8ba2d5befc05ca73d3bac8708819bbbe759e2cf9 / . / 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>
86 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]87 <li><a href="#metadata">Embedded Metadata</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]88 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]89 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]90 <li><a href="#othervalues">Other Values</a>
91 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]93 </ol>
94 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]95 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
96 <ol>
97 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]98 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
99 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]100 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
101 Global Variable</a></li>
102 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
103 Global Variable</a></li>
104 </ol>
105 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]106 <li><a href="#instref">Instruction Reference</a>
107 <ol>
108 <li><a href="#terminators">Terminator Instructions</a>
109 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]110 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
111 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]112 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
113 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]114 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]115 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 </ol>
117 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]118 <li><a href="#binaryops">Binary Operations</a>
119 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]120 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]121 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]126 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
127 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
128 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]129 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
130 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
131 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 </ol>
133 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
135 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]136 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
137 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
138 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]139 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]141 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 </ol>
143 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]144 <li><a href="#vectorops">Vector Operations</a>
145 <ol>
146 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
147 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
148 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]149 </ol>
150 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]151 <li><a href="#aggregateops">Aggregate Operations</a>
152 <ol>
153 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
154 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
155 </ol>
156 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]157 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]158 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]159 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
160 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
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
341 variable is never accessed outside of the current function... allowing it to
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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]362<p>...because the definition of <tt>%x</tt> does not dominate all of its
363 uses. The LLVM infrastructure provides a verification pass that may be used
364 to verify that an LLVM module is well formed. This pass is automatically run
365 by the parser after parsing input assembly and by the optimizer before it
366 outputs bitcode. The violations pointed out by the verifier pass indicate
367 bugs in transformation passes or input to the parser.</p>
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>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]441<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
442<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
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
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]460<p>...and 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">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]485<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]486<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
487 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 Wendlinge910b4c2009-07-20 02:29:24 +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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]493define i32 @main() { <i>; i32()* </i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]494 <i>; Convert [13 x i8]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]495 %cast210 = <a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]496 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]497
498 <i>; Call puts function to write out the string to stdout...</i>
499 <a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]500 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]501 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]502 href="#i_ret">ret</a> i32 0<br>}<br>
503</pre>
504</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]506<p>This example is made up of a <a href="#globalvars">global variable</a> named
507 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
508 a <a href="#functionstructure">function definition</a> for
509 "<tt>main</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]510
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]511<p>In general, a module is made up of a list of global values, where both
512 functions and global variables are global values. Global values are
513 represented by a pointer to a memory location (in this case, a pointer to an
514 array of char, and a pointer to a function), and have one of the
515 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]516
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]517</div>
518
519<!-- ======================================================================= -->
520<div class="doc_subsection">
521 <a name="linkage">Linkage Types</a>
522</div>
523
524<div class="doc_text">
525
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]526<p>All Global Variables and Functions have one of the following types of
527 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]528
529<dl>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]530 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]531 <dd>Global values with private linkage are only directly accessible by objects
532 in the current module. In particular, linking code into a module with an
533 private global value may cause the private to be renamed as necessary to
534 avoid collisions. Because the symbol is private to the module, all
535 references can be updated. This doesn't show up in any symbol table in the
536 object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]537
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]538 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]539 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere1eaf912009-08-24 04:32:16 +0000[diff] [blame]540 removed by the linker after evaluation. Note that (unlike private
541 symbols) linker_private symbols are subject to coalescing by the linker:
542 weak symbols get merged and redefinitions are rejected. However, unlike
543 normal strong symbols, they are removed by the linker from the final
544 linked image (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]545
Dale Johannesen2307a7f2008-05-23 23:13:41 +0000[diff] [blame]546 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]547 <dd>Similar to private, but the value shows as a local symbol
548 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
549 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]550
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]551 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]552 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]553 into the object file corresponding to the LLVM module. They exist to
554 allow inlining and other optimizations to take place given knowledge of
555 the definition of the global, which is known to be somewhere outside the
556 module. Globals with <tt>available_externally</tt> linkage are allowed to
557 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
558 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]559
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]560 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]561 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]562 the same name when linkage occurs. This is typically used to implement
563 inline functions, templates, or other code which must be generated in each
564 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
565 allowed to be discarded.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]566
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]567 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]568 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
569 <tt>linkonce</tt> linkage, except that unreferenced globals with
570 <tt>weak</tt> linkage may not be discarded. This is used for globals that
571 are declared "weak" in C source code.</dd>
572
573 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
574 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
575 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
576 global scope.
577 Symbols with "<tt>common</tt>" linkage are merged in the same way as
578 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]579 <tt>common</tt> symbols may not have an explicit section,
580 must have a zero initializer, and may not be marked '<a
581 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
582 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]583
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]584
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]585 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]586 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]587 pointer to array type. When two global variables with appending linkage
588 are linked together, the two global arrays are appended together. This is
589 the LLVM, typesafe, equivalent of having the system linker append together
590 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]591
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]592 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]593 <dd>The semantics of this linkage follow the ELF object file model: the symbol
594 is weak until linked, if not linked, the symbol becomes null instead of
595 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]596
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt>: </dt>
598 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]599 <dd>Some languages allow differing globals to be merged, such as two functions
600 with different semantics. Other languages, such as <tt>C++</tt>, ensure
601 that only equivalent globals are ever merged (the "one definition rule" -
602 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
603 and <tt>weak_odr</tt> linkage types to indicate that the global will only
604 be merged with equivalent globals. These linkage types are otherwise the
605 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]606
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]607 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]608 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]609 visible, meaning that it participates in linkage and can be used to
610 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]611</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]612
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]613<p>The next two types of linkage are targeted for Microsoft Windows platform
614 only. They are designed to support importing (exporting) symbols from (to)
615 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]616
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]617<dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]618 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]619 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]620 or variable via a global pointer to a pointer that is set up by the DLL
621 exporting the symbol. On Microsoft Windows targets, the pointer name is
622 formed by combining <code>__imp_</code> and the function or variable
623 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]624
625 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]626 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]627 pointer to a pointer in a DLL, so that it can be referenced with the
628 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
629 name is formed by combining <code>__imp_</code> and the function or
630 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]631</dl>
632
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]633<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
634 another module defined a "<tt>.LC0</tt>" variable and was linked with this
635 one, one of the two would be renamed, preventing a collision. Since
636 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
637 declarations), they are accessible outside of the current module.</p>
638
639<p>It is illegal for a function <i>declaration</i> to have any linkage type
640 other than "externally visible", <tt>dllimport</tt>
641 or <tt>extern_weak</tt>.</p>
642
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]643<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]644 or <tt>weak_odr</tt> linkages.</p>
645
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]646</div>
647
648<!-- ======================================================================= -->
649<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]650 <a name="callingconv">Calling Conventions</a>
651</div>
652
653<div class="doc_text">
654
655<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]656 and <a href="#i_invoke">invokes</a> can all have an optional calling
657 convention specified for the call. The calling convention of any pair of
658 dynamic caller/callee must match, or the behavior of the program is
659 undefined. The following calling conventions are supported by LLVM, and more
660 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]661
662<dl>
663 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]664 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]665 specified) matches the target C calling conventions. This calling
666 convention supports varargs function calls and tolerates some mismatch in
667 the declared prototype and implemented declaration of the function (as
668 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]669
670 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]671 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]672 (e.g. by passing things in registers). This calling convention allows the
673 target to use whatever tricks it wants to produce fast code for the
674 target, without having to conform to an externally specified ABI
675 (Application Binary Interface). Implementations of this convention should
676 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
677 optimization</a> to be supported. This calling convention does not
678 support varargs and requires the prototype of all callees to exactly match
679 the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]680
681 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]682 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]683 as possible under the assumption that the call is not commonly executed.
684 As such, these calls often preserve all registers so that the call does
685 not break any live ranges in the caller side. This calling convention
686 does not support varargs and requires the prototype of all callees to
687 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]688
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]689 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]690 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]691 target-specific calling conventions to be used. Target specific calling
692 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]693</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694
695<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]696 support Pascal conventions or any other well-known target-independent
697 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]698
699</div>
700
701<!-- ======================================================================= -->
702<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]703 <a name="visibility">Visibility Styles</a>
704</div>
705
706<div class="doc_text">
707
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]708<p>All Global Variables and Functions have one of the following visibility
709 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]710
711<dl>
712 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]713 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714 that the declaration is visible to other modules and, in shared libraries,
715 means that the declared entity may be overridden. On Darwin, default
716 visibility means that the declaration is visible to other modules. Default
717 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]718
719 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]720 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]721 object if they are in the same shared object. Usually, hidden visibility
722 indicates that the symbol will not be placed into the dynamic symbol
723 table, so no other module (executable or shared library) can reference it
724 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]725
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]726 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]727 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]728 the dynamic symbol table, but that references within the defining module
729 will bind to the local symbol. That is, the symbol cannot be overridden by
730 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]731</dl>
732
733</div>
734
735<!-- ======================================================================= -->
736<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]737 <a name="namedtypes">Named Types</a>
738</div>
739
740<div class="doc_text">
741
742<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]743 it easier to read the IR and make the IR more condensed (particularly when
744 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]745
746<div class="doc_code">
747<pre>
748%mytype = type { %mytype*, i32 }
749</pre>
750</div>
751
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]752<p>You may give a name to any <a href="#typesystem">type</a> except
753 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
754 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]755
756<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]757 and that you can therefore specify multiple names for the same type. This
758 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
759 uses structural typing, the name is not part of the type. When printing out
760 LLVM IR, the printer will pick <em>one name</em> to render all types of a
761 particular shape. This means that if you have code where two different
762 source types end up having the same LLVM type, that the dumper will sometimes
763 print the "wrong" or unexpected type. This is an important design point and
764 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]765
766</div>
767
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]768<!-- ======================================================================= -->
769<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]770 <a name="globalvars">Global Variables</a>
771</div>
772
773<div class="doc_text">
774
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]775<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]776 instead of run-time. Global variables may optionally be initialized, may
777 have an explicit section to be placed in, and may have an optional explicit
778 alignment specified. A variable may be defined as "thread_local", which
779 means that it will not be shared by threads (each thread will have a
780 separated copy of the variable). A variable may be defined as a global
781 "constant," which indicates that the contents of the variable
782 will <b>never</b> be modified (enabling better optimization, allowing the
783 global data to be placed in the read-only section of an executable, etc).
784 Note that variables that need runtime initialization cannot be marked
785 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]786
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]787<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
788 constant, even if the final definition of the global is not. This capability
789 can be used to enable slightly better optimization of the program, but
790 requires the language definition to guarantee that optimizations based on the
791 'constantness' are valid for the translation units that do not include the
792 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]793
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]794<p>As SSA values, global variables define pointer values that are in scope
795 (i.e. they dominate) all basic blocks in the program. Global variables
796 always define a pointer to their "content" type because they describe a
797 region of memory, and all memory objects in LLVM are accessed through
798 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]799
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]800<p>A global variable may be declared to reside in a target-specific numbered
801 address space. For targets that support them, address spaces may affect how
802 optimizations are performed and/or what target instructions are used to
803 access the variable. The default address space is zero. The address space
804 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]805
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]806<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]807 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]808
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]809<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]810 the alignment is set to zero, the alignment of the global is set by the
811 target to whatever it feels convenient. If an explicit alignment is
812 specified, the global is forced to have at least that much alignment. All
813 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]814
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]815<p>For example, the following defines a global in a numbered address space with
816 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]817
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]818<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]819<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]820@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]821</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]822</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]823
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]824</div>
825
826
827<!-- ======================================================================= -->
828<div class="doc_subsection">
829 <a name="functionstructure">Functions</a>
830</div>
831
832<div class="doc_text">
833
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]834<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
835 optional <a href="#linkage">linkage type</a>, an optional
836 <a href="#visibility">visibility style</a>, an optional
837 <a href="#callingconv">calling convention</a>, a return type, an optional
838 <a href="#paramattrs">parameter attribute</a> for the return type, a function
839 name, a (possibly empty) argument list (each with optional
840 <a href="#paramattrs">parameter attributes</a>), optional
841 <a href="#fnattrs">function attributes</a>, an optional section, an optional
842 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
843 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]845<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
846 optional <a href="#linkage">linkage type</a>, an optional
847 <a href="#visibility">visibility style</a>, an optional
848 <a href="#callingconv">calling convention</a>, a return type, an optional
849 <a href="#paramattrs">parameter attribute</a> for the return type, a function
850 name, a possibly empty list of arguments, an optional alignment, and an
851 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]852
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]853<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]854 (Control Flow Graph) for the function. Each basic block may optionally start
855 with a label (giving the basic block a symbol table entry), contains a list
856 of instructions, and ends with a <a href="#terminators">terminator</a>
857 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]858
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]859<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]860 executed on entrance to the function, and it is not allowed to have
861 predecessor basic blocks (i.e. there can not be any branches to the entry
862 block of a function). Because the block can have no predecessors, it also
863 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]864
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]865<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]866 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]867
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]868<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]869 the alignment is set to zero, the alignment of the function is set by the
870 target to whatever it feels convenient. If an explicit alignment is
871 specified, the function is forced to have at least that much alignment. All
872 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]873
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]874<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]875<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]876<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]877define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]878 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
879 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
880 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
881 [<a href="#gc">gc</a>] { ... }
882</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]883</div>
884
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]885</div>
886
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]887<!-- ======================================================================= -->
888<div class="doc_subsection">
889 <a name="aliasstructure">Aliases</a>
890</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]891
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]892<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]893
894<p>Aliases act as "second name" for the aliasee value (which can be either
895 function, global variable, another alias or bitcast of global value). Aliases
896 may have an optional <a href="#linkage">linkage type</a>, and an
897 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]898
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]899<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]900<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]901<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]902@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]903</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]904</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]905
906</div>
907
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]908<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]909<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]910
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]911<div class="doc_text">
912
913<p>The return type and each parameter of a function type may have a set of
914 <i>parameter attributes</i> associated with them. Parameter attributes are
915 used to communicate additional information about the result or parameters of
916 a function. Parameter attributes are considered to be part of the function,
917 not of the function type, so functions with different parameter attributes
918 can have the same function type.</p>
919
920<p>Parameter attributes are simple keywords that follow the type specified. If
921 multiple parameter attributes are needed, they are space separated. For
922 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]923
924<div class="doc_code">
925<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]926declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]927declare i32 @atoi(i8 zeroext)
928declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]929</pre>
930</div>
931
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]932<p>Note that any attributes for the function result (<tt>nounwind</tt>,
933 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]934
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]935<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]936
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]937<dl>
938 <dt><tt>zeroext</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]939 <dd>This indicates to the code generator that the parameter or return value
940 should be zero-extended to a 32-bit value by the caller (for a parameter)
941 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]942
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]943 <dt><tt>signext</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]944 <dd>This indicates to the code generator that the parameter or return value
945 should be sign-extended to a 32-bit value by the caller (for a parameter)
946 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]947
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]948 <dt><tt>inreg</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]949 <dd>This indicates that this parameter or return value should be treated in a
950 special target-dependent fashion during while emitting code for a function
951 call or return (usually, by putting it in a register as opposed to memory,
952 though some targets use it to distinguish between two different kinds of
953 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]954
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]955 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]956 <dd>This indicates that the pointer parameter should really be passed by value
957 to the function. The attribute implies that a hidden copy of the pointee
958 is made between the caller and the callee, so the callee is unable to
959 modify the value in the callee. This attribute is only valid on LLVM
960 pointer arguments. It is generally used to pass structs and arrays by
961 value, but is also valid on pointers to scalars. The copy is considered
962 to belong to the caller not the callee (for example,
963 <tt><a href="#readonly">readonly</a></tt> functions should not write to
964 <tt>byval</tt> parameters). This is not a valid attribute for return
965 values. The byval attribute also supports specifying an alignment with
966 the align attribute. This has a target-specific effect on the code
967 generator that usually indicates a desired alignment for the synthesized
968 stack slot.</dd>
969
970 <dt><tt>sret</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]971 <dd>This indicates that the pointer parameter specifies the address of a
972 structure that is the return value of the function in the source program.
973 This pointer must be guaranteed by the caller to be valid: loads and
974 stores to the structure may be assumed by the callee to not to trap. This
975 may only be applied to the first parameter. This is not a valid attribute
976 for return values. </dd>
977
978 <dt><tt>noalias</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]979 <dd>This indicates that the pointer does not alias any global or any other
980 parameter. The caller is responsible for ensuring that this is the
981 case. On a function return value, <tt>noalias</tt> additionally indicates
982 that the pointer does not alias any other pointers visible to the
983 caller. For further details, please see the discussion of the NoAlias
984 response in
985 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
986 analysis</a>.</dd>
987
988 <dt><tt>nocapture</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]989 <dd>This indicates that the callee does not make any copies of the pointer
990 that outlive the callee itself. This is not a valid attribute for return
991 values.</dd>
992
993 <dt><tt>nest</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]994 <dd>This indicates that the pointer parameter can be excised using the
995 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
996 attribute for return values.</dd>
997</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]998
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]999</div>
1000
1001<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1002<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1003 <a name="gc">Garbage Collector Names</a>
1004</div>
1005
1006<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1007
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1008<p>Each function may specify a garbage collector name, which is simply a
1009 string:</p>
1010
1011<div class="doc_code">
1012<pre>
1013define void @f() gc "name" { ...
1014</pre>
1015</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1016
1017<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1018 collector which will cause the compiler to alter its output in order to
1019 support the named garbage collection algorithm.</p>
1020
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1021</div>
1022
1023<!-- ======================================================================= -->
1024<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1025 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1026</div>
1027
1028<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1029
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1030<p>Function attributes are set to communicate additional information about a
1031 function. Function attributes are considered to be part of the function, not
1032 of the function type, so functions with different parameter attributes can
1033 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1034
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1035<p>Function attributes are simple keywords that follow the type specified. If
1036 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1037
1038<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1039<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1040define void @f() noinline { ... }
1041define void @f() alwaysinline { ... }
1042define void @f() alwaysinline optsize { ... }
1043define void @f() optsize
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1044</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1045</div>
1046
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1047<dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1048 <dt><tt>alwaysinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1049 <dd>This attribute indicates that the inliner should attempt to inline this
1050 function into callers whenever possible, ignoring any active inlining size
1051 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1052
Dale Johannesende86d472009-08-26 01:08:21 +0000[diff] [blame]1053 <dt><tt>inlinehint</tt></dt>
1054 <dd>This attribute indicates that the source code contained a hint that inlining
1055 this function is desirable (such as the "inline" keyword in C/C++). It
1056 is just a hint; it imposes no requirements on the inliner.</dd>
1057
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1058 <dt><tt>noinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This attribute indicates that the inliner should never inline this
1060 function in any situation. This attribute may not be used together with
1061 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1062
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1063 <dt><tt>optsize</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This attribute suggests that optimization passes and code generator passes
1065 make choices that keep the code size of this function low, and otherwise
1066 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1067
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1068 <dt><tt>noreturn</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This function attribute indicates that the function never returns
1070 normally. This produces undefined behavior at runtime if the function
1071 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1072
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1073 <dt><tt>nounwind</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1074 <dd>This function attribute indicates that the function never returns with an
1075 unwind or exceptional control flow. If the function does unwind, its
1076 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1077
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1078 <dt><tt>readnone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1079 <dd>This attribute indicates that the function computes its result (or decides
1080 to unwind an exception) based strictly on its arguments, without
1081 dereferencing any pointer arguments or otherwise accessing any mutable
1082 state (e.g. memory, control registers, etc) visible to caller functions.
1083 It does not write through any pointer arguments
1084 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1085 changes any state visible to callers. This means that it cannot unwind
1086 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1087 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1088
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1089 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1090 <dd>This attribute indicates that the function does not write through any
1091 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1092 arguments) or otherwise modify any state (e.g. memory, control registers,
1093 etc) visible to caller functions. It may dereference pointer arguments
1094 and read state that may be set in the caller. A readonly function always
1095 returns the same value (or unwinds an exception identically) when called
1096 with the same set of arguments and global state. It cannot unwind an
1097 exception by calling the <tt>C++</tt> exception throwing methods, but may
1098 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1099
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1100 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1101 <dd>This attribute indicates that the function should emit a stack smashing
1102 protector. It is in the form of a "canary"&mdash;a random value placed on
1103 the stack before the local variables that's checked upon return from the
1104 function to see if it has been overwritten. A heuristic is used to
1105 determine if a function needs stack protectors or not.<br>
1106<br>
1107 If a function that has an <tt>ssp</tt> attribute is inlined into a
1108 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1109 function will have an <tt>ssp</tt> attribute.</dd>
1110
1111 <dt><tt>sspreq</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1112 <dd>This attribute indicates that the function should <em>always</em> emit a
1113 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1114 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1115<br>
1116 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1117 function that doesn't have an <tt>sspreq</tt> attribute or which has
1118 an <tt>ssp</tt> attribute, then the resulting function will have
1119 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1120
1121 <dt><tt>noredzone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1122 <dd>This attribute indicates that the code generator should not use a red
1123 zone, even if the target-specific ABI normally permits it.</dd>
1124
1125 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1126 <dd>This attributes disables implicit floating point instructions.</dd>
1127
1128 <dt><tt>naked</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1129 <dd>This attribute disables prologue / epilogue emission for the function.
1130 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1131</dl>
1132
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1133</div>
1134
1135<!-- ======================================================================= -->
1136<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1137 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1138</div>
1139
1140<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1141
1142<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1143 the GCC "file scope inline asm" blocks. These blocks are internally
1144 concatenated by LLVM and treated as a single unit, but may be separated in
1145 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1146
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1147<div class="doc_code">
1148<pre>
1149module asm "inline asm code goes here"
1150module asm "more can go here"
1151</pre>
1152</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1153
1154<p>The strings can contain any character by escaping non-printable characters.
1155 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]1156 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1157
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1158<p>The inline asm code is simply printed to the machine code .s file when
1159 assembly code is generated.</p>
1160
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1161</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1162
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1163<!-- ======================================================================= -->
1164<div class="doc_subsection">
1165 <a name="datalayout">Data Layout</a>
1166</div>
1167
1168<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1169
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1170<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1171 data is to be laid out in memory. The syntax for the data layout is
1172 simply:</p>
1173
1174<div class="doc_code">
1175<pre>
1176target datalayout = "<i>layout specification</i>"
1177</pre>
1178</div>
1179
1180<p>The <i>layout specification</i> consists of a list of specifications
1181 separated by the minus sign character ('-'). Each specification starts with
1182 a letter and may include other information after the letter to define some
1183 aspect of the data layout. The specifications accepted are as follows:</p>
1184
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1185<dl>
1186 <dt><tt>E</tt></dt>
1187 <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]1188 bits with the most significance have the lowest address location.</dd>
1189
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1190 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1191 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1192 the bits with the least significance have the lowest address
1193 location.</dd>
1194
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1195 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1196 <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]1197 <i>preferred</i> alignments. All sizes are in bits. Specifying
1198 the <i>pref</i> alignment is optional. If omitted, the
1199 preceding <tt>:</tt> should be omitted too.</dd>
1200
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1201 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1202 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1203 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1204
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1205 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1206 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1207 <i>size</i>.</dd>
1208
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1209 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1210 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1211 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1212 (double).</dd>
1213
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1214 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1215 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1216 <i>size</i>.</dd>
1217
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1218 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1219 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1220 <i>size</i>.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1221</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1222
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1223<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1224 default set of specifications which are then (possibly) overriden by the
1225 specifications in the <tt>datalayout</tt> keyword. The default specifications
1226 are given in this list:</p>
1227
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1228<ul>
1229 <li><tt>E</tt> - big endian</li>
1230 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1231 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1232 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1233 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1234 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1235 <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]1236 alignment of 64-bits</li>
1237 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1238 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1239 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1240 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1241 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1242 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1243</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1244
1245<p>When LLVM is determining the alignment for a given type, it uses the
1246 following rules:</p>
1247
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1248<ol>
1249 <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]1250 specification is used.</li>
1251
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1252 <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]1253 smallest integer type that is larger than the bitwidth of the sought type
1254 is used. If none of the specifications are larger than the bitwidth then
1255 the the largest integer type is used. For example, given the default
1256 specifications above, the i7 type will use the alignment of i8 (next
1257 largest) while both i65 and i256 will use the alignment of i64 (largest
1258 specified).</li>
1259
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1260 <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]1261 largest vector type that is smaller than the sought vector type will be
1262 used as a fall back. This happens because &lt;128 x double&gt; can be
1263 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1264</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1265
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1266</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1267
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1268<!-- ======================================================================= -->
1269<div class="doc_subsection">
1270 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1271</div>
1272
1273<div class="doc_text">
1274
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1275<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1276with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1277is undefined. Pointer values are associated with address ranges
1278according to the following rules:</p>
1279
1280<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1281 <li>A pointer value formed from a
1282 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1283 is associated with the addresses associated with the first operand
1284 of the <tt>getelementptr</tt>.</li>
1285 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1286 range of the variable's storage.</li>
1287 <li>The result value of an allocation instruction is associated with
1288 the address range of the allocated storage.</li>
1289 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1290 no address.</li>
1291 <li>A pointer value formed by an
1292 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1293 address ranges of all pointer values that contribute (directly or
1294 indirectly) to the computation of the pointer's value.</li>
1295 <li>The result value of a
1296 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1297 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1298 <li>An integer constant other than zero or a pointer value returned
1299 from a function not defined within LLVM may be associated with address
1300 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1301 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1302 allocated by mechanisms provided by LLVM.</li>
1303 </ul>
1304
1305<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1306<tt><a href="#i_load">load</a></tt> merely indicates the size and
1307alignment of the memory from which to load, as well as the
1308interpretation of the value. The first operand of a
1309<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1310and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1311
1312<p>Consequently, type-based alias analysis, aka TBAA, aka
1313<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1314LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1315additional information which specialized optimization passes may use
1316to implement type-based alias analysis.</p>
1317
1318</div>
1319
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1320<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1321<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1322<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1323
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1324<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1325
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1326<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1327 intermediate representation. Being typed enables a number of optimizations
1328 to be performed on the intermediate representation directly, without having
1329 to do extra analyses on the side before the transformation. A strong type
1330 system makes it easier to read the generated code and enables novel analyses
1331 and transformations that are not feasible to perform on normal three address
1332 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1333
1334</div>
1335
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1336<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1337<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1338Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1340<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1341
1342<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1343
1344<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1345 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1346 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1347 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1348 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1349 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1350 </tr>
1351 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1352 <td><a href="#t_floating">floating point</a></td>
1353 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1354 </tr>
1355 <tr>
1356 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1357 <td><a href="#t_integer">integer</a>,
1358 <a href="#t_floating">floating point</a>,
1359 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1360 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1361 <a href="#t_struct">structure</a>,
1362 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1363 <a href="#t_label">label</a>,
1364 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1365 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1366 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1367 <tr>
1368 <td><a href="#t_primitive">primitive</a></td>
1369 <td><a href="#t_label">label</a>,
1370 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1371 <a href="#t_floating">floating point</a>,
1372 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1373 </tr>
1374 <tr>
1375 <td><a href="#t_derived">derived</a></td>
1376 <td><a href="#t_integer">integer</a>,
1377 <a href="#t_array">array</a>,
1378 <a href="#t_function">function</a>,
1379 <a href="#t_pointer">pointer</a>,
1380 <a href="#t_struct">structure</a>,
1381 <a href="#t_pstruct">packed structure</a>,
1382 <a href="#t_vector">vector</a>,
1383 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1384 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1385 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1386 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1387</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1388
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1389<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1390 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1391 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1393</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1394
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1395<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1396<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1397
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1398<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1399
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1400<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1401 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1402
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1403</div>
1404
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1405<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1406<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1407
1408<div class="doc_text">
1409
1410<h5>Overview:</h5>
1411<p>The integer type is a very simple type that simply specifies an arbitrary
1412 bit width for the integer type desired. Any bit width from 1 bit to
1413 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1414
1415<h5>Syntax:</h5>
1416<pre>
1417 iN
1418</pre>
1419
1420<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1421 value.</p>
1422
1423<h5>Examples:</h5>
1424<table class="layout">
1425 <tr class="layout">
1426 <td class="left"><tt>i1</tt></td>
1427 <td class="left">a single-bit integer.</td>
1428 </tr>
1429 <tr class="layout">
1430 <td class="left"><tt>i32</tt></td>
1431 <td class="left">a 32-bit integer.</td>
1432 </tr>
1433 <tr class="layout">
1434 <td class="left"><tt>i1942652</tt></td>
1435 <td class="left">a really big integer of over 1 million bits.</td>
1436 </tr>
1437</table>
1438
1439<p>Note that the code generator does not yet support large integer types to be
1440 used as function return types. The specific limit on how large a return type
1441 the code generator can currently handle is target-dependent; currently it's
1442 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
1443
1444</div>
1445
1446<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1447<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1448
1449<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1450
1451<table>
1452 <tbody>
1453 <tr><th>Type</th><th>Description</th></tr>
1454 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1455 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1456 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1457 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1458 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1459 </tbody>
1460</table>
1461
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1462</div>
1463
1464<!-- _______________________________________________________________________ -->
1465<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1466
1467<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1468
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1469<h5>Overview:</h5>
1470<p>The void type does not represent any value and has no size.</p>
1471
1472<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1473<pre>
1474 void
1475</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1476
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1477</div>
1478
1479<!-- _______________________________________________________________________ -->
1480<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1481
1482<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1483
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1484<h5>Overview:</h5>
1485<p>The label type represents code labels.</p>
1486
1487<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1488<pre>
1489 label
1490</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1491
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1492</div>
1493
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1494<!-- _______________________________________________________________________ -->
1495<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1496
1497<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1498
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1499<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1500<p>The metadata type represents embedded metadata. No derived types may be
1501 created from metadata except for <a href="#t_function">function</a>
1502 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1503
1504<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1505<pre>
1506 metadata
1507</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1508
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1509</div>
1510
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1511
1512<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1513<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1514
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1515<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1516
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1517<p>The real power in LLVM comes from the derived types in the system. This is
1518 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1519 useful types. Each of these types contain one or more element types which
1520 may be a primitive type, or another derived type. For example, it is
1521 possible to have a two dimensional array, using an array as the element type
1522 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1523
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1524</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1525
1526<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1527<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1528
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1529<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1531<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1532<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1533 sequentially in memory. The array type requires a size (number of elements)
1534 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1535
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1536<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1537<pre>
1538 [&lt;# elements&gt; x &lt;elementtype&gt;]
1539</pre>
1540
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1541<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1542 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1543
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1544<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1545<table class="layout">
1546 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1547 <td class="left"><tt>[40 x i32]</tt></td>
1548 <td class="left">Array of 40 32-bit integer values.</td>
1549 </tr>
1550 <tr class="layout">
1551 <td class="left"><tt>[41 x i32]</tt></td>
1552 <td class="left">Array of 41 32-bit integer values.</td>
1553 </tr>
1554 <tr class="layout">
1555 <td class="left"><tt>[4 x i8]</tt></td>
1556 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1557 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1558</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1559<p>Here are some examples of multidimensional arrays:</p>
1560<table class="layout">
1561 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1562 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1563 <td class="left">3x4 array of 32-bit integer values.</td>
1564 </tr>
1565 <tr class="layout">
1566 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1567 <td class="left">12x10 array of single precision floating point values.</td>
1568 </tr>
1569 <tr class="layout">
1570 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1571 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1572 </tr>
1573</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1574
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1575<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1576 length array. Normally, accesses past the end of an array are undefined in
1577 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1578 a special case, however, zero length arrays are recognized to be variable
1579 length. This allows implementation of 'pascal style arrays' with the LLVM
1580 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1581
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1582<p>Note that the code generator does not yet support large aggregate types to be
1583 used as function return types. The specific limit on how large an aggregate
1584 return type the code generator can currently handle is target-dependent, and
1585 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1586
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1587</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1589<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1590<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1591
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1592<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1594<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1595<p>The function type can be thought of as a function signature. It consists of
1596 a return type and a list of formal parameter types. The return type of a
1597 function type is a scalar type, a void type, or a struct type. If the return
1598 type is a struct type then all struct elements must be of first class types,
1599 and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1600
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1601<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1602<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1603 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1604</pre>
1605
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1606<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]1607 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1608 which indicates that the function takes a variable number of arguments.
1609 Variable argument functions can access their arguments with
1610 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1611 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1612 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1613
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1614<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1615<table class="layout">
1616 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1617 <td class="left"><tt>i32 (i32)</tt></td>
1618 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1619 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1620 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1621 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1622 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1623 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1624 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1625 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1626 <tt>float</tt>.
1627 </td>
1628 </tr><tr class="layout">
1629 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1630 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1631 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1632 which returns an integer. This is the signature for <tt>printf</tt> in
1633 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1634 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1635 </tr><tr class="layout">
1636 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1637 <td class="left">A function taking an <tt>i32</tt>, returning a
1638 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1639 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1640 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1641</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1642
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1643</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1644
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1645<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1646<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1647
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1648<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1649
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1650<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1651<p>The structure type is used to represent a collection of data members together
1652 in memory. The packing of the field types is defined to match the ABI of the
1653 underlying processor. The elements of a structure may be any type that has a
1654 size.</p>
1655
1656<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1657 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1658 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1659
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1660<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1661<pre>
1662 { &lt;type list&gt; }
1663</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1664
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1665<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1666<table class="layout">
1667 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1668 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1669 <td class="left">A triple of three <tt>i32</tt> values</td>
1670 </tr><tr class="layout">
1671 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1672 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1673 second element is a <a href="#t_pointer">pointer</a> to a
1674 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1675 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1676 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1677</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1678
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1679<p>Note that the code generator does not yet support large aggregate types to be
1680 used as function return types. The specific limit on how large an aggregate
1681 return type the code generator can currently handle is target-dependent, and
1682 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1683
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1684</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1685
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1686<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1687<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1688</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1689
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1690<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1691
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1692<h5>Overview:</h5>
1693<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1694 together in memory. There is no padding between fields. Further, the
1695 alignment of a packed structure is 1 byte. The elements of a packed
1696 structure may be any type that has a size.</p>
1697
1698<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1699 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1700 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1701
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1702<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1703<pre>
1704 &lt; { &lt;type list&gt; } &gt;
1705</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1706
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1707<h5>Examples:</h5>
1708<table class="layout">
1709 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1710 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1711 <td class="left">A triple of three <tt>i32</tt> values</td>
1712 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1713 <td class="left">
1714<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1715 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1716 second element is a <a href="#t_pointer">pointer</a> to a
1717 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1718 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1719 </tr>
1720</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1721
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1722</div>
1723
1724<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1725<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1726
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1727<div class="doc_text">
1728
1729<h5>Overview:</h5>
1730<p>As in many languages, the pointer type represents a pointer or reference to
1731 another object, which must live in memory. Pointer types may have an optional
1732 address space attribute defining the target-specific numbered address space
1733 where the pointed-to object resides. The default address space is zero.</p>
1734
1735<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1736 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1737
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1738<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1739<pre>
1740 &lt;type&gt; *
1741</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1742
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1743<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1744<table class="layout">
1745 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1746 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1747 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1748 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1749 </tr>
1750 <tr class="layout">
1751 <td class="left"><tt>i32 (i32 *) *</tt></td>
1752 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1753 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1754 <tt>i32</tt>.</td>
1755 </tr>
1756 <tr class="layout">
1757 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1758 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1759 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1760 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1761</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1762
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1763</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1764
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1765<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1766<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1767
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1768<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1769
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1770<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1771<p>A vector type is a simple derived type that represents a vector of elements.
1772 Vector types are used when multiple primitive data are operated in parallel
1773 using a single instruction (SIMD). A vector type requires a size (number of
1774 elements) and an underlying primitive data type. Vectors must have a power
1775 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1776 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1777
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1778<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1779<pre>
1780 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1781</pre>
1782
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1783<p>The number of elements is a constant integer value; elementtype may be any
1784 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1785
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1786<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1787<table class="layout">
1788 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1789 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1790 <td class="left">Vector of 4 32-bit integer values.</td>
1791 </tr>
1792 <tr class="layout">
1793 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1794 <td class="left">Vector of 8 32-bit floating-point values.</td>
1795 </tr>
1796 <tr class="layout">
1797 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1798 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1799 </tr>
1800</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1801
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1802<p>Note that the code generator does not yet support large vector types to be
1803 used as function return types. The specific limit on how large a vector
1804 return type codegen can currently handle is target-dependent; currently it's
1805 often a few times longer than a hardware vector register.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1806
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1807</div>
1808
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1809<!-- _______________________________________________________________________ -->
1810<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1811<div class="doc_text">
1812
1813<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1814<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1815 corresponds (for example) to the C notion of a forward declared structure
1816 type. In LLVM, opaque types can eventually be resolved to any type (not just
1817 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1818
1819<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1820<pre>
1821 opaque
1822</pre>
1823
1824<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1825<table class="layout">
1826 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1827 <td class="left"><tt>opaque</tt></td>
1828 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1829 </tr>
1830</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1831
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1832</div>
1833
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1834<!-- ======================================================================= -->
1835<div class="doc_subsection">
1836 <a name="t_uprefs">Type Up-references</a>
1837</div>
1838
1839<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1840
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1841<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1842<p>An "up reference" allows you to refer to a lexically enclosing type without
1843 requiring it to have a name. For instance, a structure declaration may
1844 contain a pointer to any of the types it is lexically a member of. Example
1845 of up references (with their equivalent as named type declarations)
1846 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1847
1848<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1849 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1850 { \2 }* %y = type { %y }*
1851 \1* %z = type %z*
1852</pre>
1853
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1854<p>An up reference is needed by the asmprinter for printing out cyclic types
1855 when there is no declared name for a type in the cycle. Because the
1856 asmprinter does not want to print out an infinite type string, it needs a
1857 syntax to handle recursive types that have no names (all names are optional
1858 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1859
1860<h5>Syntax:</h5>
1861<pre>
1862 \&lt;level&gt;
1863</pre>
1864
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1865<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]1866
1867<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1868<table class="layout">
1869 <tr class="layout">
1870 <td class="left"><tt>\1*</tt></td>
1871 <td class="left">Self-referential pointer.</td>
1872 </tr>
1873 <tr class="layout">
1874 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1875 <td class="left">Recursive structure where the upref refers to the out-most
1876 structure.</td>
1877 </tr>
1878</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1879
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1880</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1881
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1882<!-- *********************************************************************** -->
1883<div class="doc_section"> <a name="constants">Constants</a> </div>
1884<!-- *********************************************************************** -->
1885
1886<div class="doc_text">
1887
1888<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1889 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1890
1891</div>
1892
1893<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1894<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1895
1896<div class="doc_text">
1897
1898<dl>
1899 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1900 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1901 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1902
1903 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1904 <dd>Standard integers (such as '4') are constants of
1905 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1906 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1907
1908 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1909 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1910 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1911 notation (see below). The assembler requires the exact decimal value of a
1912 floating-point constant. For example, the assembler accepts 1.25 but
1913 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1914 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1915
1916 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1917 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1918 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1919</dl>
1920
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1921<p>The one non-intuitive notation for constants is the hexadecimal form of
1922 floating point constants. For example, the form '<tt>double
1923 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1924 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1925 constants are required (and the only time that they are generated by the
1926 disassembler) is when a floating point constant must be emitted but it cannot
1927 be represented as a decimal floating point number in a reasonable number of
1928 digits. For example, NaN's, infinities, and other special values are
1929 represented in their IEEE hexadecimal format so that assembly and disassembly
1930 do not cause any bits to change in the constants.</p>
1931
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]1932<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1933 represented using the 16-digit form shown above (which matches the IEEE754
1934 representation for double); float values must, however, be exactly
1935 representable as IEE754 single precision. Hexadecimal format is always used
1936 for long double, and there are three forms of long double. The 80-bit format
1937 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1938 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1939 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1940 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1941 currently supported target uses this format. Long doubles will only work if
1942 they match the long double format on your target. All hexadecimal formats
1943 are big-endian (sign bit at the left).</p>
1944
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1945</div>
1946
1947<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1948<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]1949<a name="aggregateconstants"></a> <!-- old anchor -->
1950<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1951</div>
1952
1953<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1954
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1955<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1956 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1957
1958<dl>
1959 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1960 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1961 type definitions (a comma separated list of elements, surrounded by braces
1962 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1963 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1964 Structure constants must have <a href="#t_struct">structure type</a>, and
1965 the number and types of elements must match those specified by the
1966 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1967
1968 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1969 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1970 definitions (a comma separated list of elements, surrounded by square
1971 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1972 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1973 the number and types of elements must match those specified by the
1974 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1975
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1976 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1977 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1978 definitions (a comma separated list of elements, surrounded by
1979 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1980 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1981 have <a href="#t_vector">vector type</a>, and the number and types of
1982 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1983
1984 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1985 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1986 value to zero of <em>any</em> type, including scalar and aggregate types.
1987 This is often used to avoid having to print large zero initializers
1988 (e.g. for large arrays) and is always exactly equivalent to using explicit
1989 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]1990
1991 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]1992 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1993 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1994 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1995 be interpreted as part of the instruction stream, metadata is a place to
1996 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1997</dl>
1998
1999</div>
2000
2001<!-- ======================================================================= -->
2002<div class="doc_subsection">
2003 <a name="globalconstants">Global Variable and Function Addresses</a>
2004</div>
2005
2006<div class="doc_text">
2007
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2008<p>The addresses of <a href="#globalvars">global variables</a>
2009 and <a href="#functionstructure">functions</a> are always implicitly valid
2010 (link-time) constants. These constants are explicitly referenced when
2011 the <a href="#identifiers">identifier for the global</a> is used and always
2012 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2013 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2014
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2015<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2016<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2017@X = global i32 17
2018@Y = global i32 42
2019@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2020</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2021</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2022
2023</div>
2024
2025<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2026<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2027<div class="doc_text">
2028
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2029<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]2030 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2031 Undefined values may be of any type (other than label or void) and be used
2032 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2033
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2034<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2035 program is well defined no matter what value is used. This gives the
2036 compiler more freedom to optimize. Here are some examples of (potentially
2037 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2038
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2039
2040<div class="doc_code">
2041<pre>
2042 %A = add %X, undef
2043 %B = sub %X, undef
2044 %C = xor %X, undef
2045Safe:
2046 %A = undef
2047 %B = undef
2048 %C = undef
2049</pre>
2050</div>
2051
2052<p>This is safe because all of the output bits are affected by the undef bits.
2053Any output bit can have a zero or one depending on the input bits.</p>
2054
2055<div class="doc_code">
2056<pre>
2057 %A = or %X, undef
2058 %B = and %X, undef
2059Safe:
2060 %A = -1
2061 %B = 0
2062Unsafe:
2063 %A = undef
2064 %B = undef
2065</pre>
2066</div>
2067
2068<p>These logical operations have bits that are not always affected by the input.
2069For example, if "%X" has a zero bit, then the output of the 'and' operation will
2070always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2071such, it is unsafe to optimize or assume that the result of the and is undef.
2072However, it is safe to assume that all bits of the undef could be 0, and
2073optimize the and to 0. Likewise, it is safe to assume that all the bits of
2074the undef operand to the or could be set, allowing the or to be folded to
2075-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2076
2077<div class="doc_code">
2078<pre>
2079 %A = select undef, %X, %Y
2080 %B = select undef, 42, %Y
2081 %C = select %X, %Y, undef
2082Safe:
2083 %A = %X (or %Y)
2084 %B = 42 (or %Y)
2085 %C = %Y
2086Unsafe:
2087 %A = undef
2088 %B = undef
2089 %C = undef
2090</pre>
2091</div>
2092
2093<p>This set of examples show that undefined select (and conditional branch)
2094conditions can go "either way" but they have to come from one of the two
2095operands. In the %A example, if %X and %Y were both known to have a clear low
2096bit, then %A would have to have a cleared low bit. However, in the %C example,
2097the optimizer is allowed to assume that the undef operand could be the same as
2098%Y, allowing the whole select to be eliminated.</p>
2099
2100
2101<div class="doc_code">
2102<pre>
2103 %A = xor undef, undef
2104
2105 %B = undef
2106 %C = xor %B, %B
2107
2108 %D = undef
2109 %E = icmp lt %D, 4
2110 %F = icmp gte %D, 4
2111
2112Safe:
2113 %A = undef
2114 %B = undef
2115 %C = undef
2116 %D = undef
2117 %E = undef
2118 %F = undef
2119</pre>
2120</div>
2121
2122<p>This example points out that two undef operands are not necessarily the same.
2123This can be surprising to people (and also matches C semantics) where they
2124assume that "X^X" is always zero, even if X is undef. This isn't true for a
2125number of reasons, but the short answer is that an undef "variable" can
2126arbitrarily change its value over its "live range". This is true because the
2127"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2128logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2129so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2130to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2131would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2132
2133<div class="doc_code">
2134<pre>
2135 %A = fdiv undef, %X
2136 %B = fdiv %X, undef
2137Safe:
2138 %A = undef
2139b: unreachable
2140</pre>
2141</div>
2142
2143<p>These examples show the crucial difference between an <em>undefined
2144value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2145allowed to have an arbitrary bit-pattern. This means that the %A operation
2146can be constant folded to undef because the undef could be an SNaN, and fdiv is
2147not (currently) defined on SNaN's. However, in the second example, we can make
2148a more aggressive assumption: because the undef is allowed to be an arbitrary
2149value, 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]2150has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2151does not execute at all. This allows us to delete the divide and all code after
2152it: since the undefined operation "can't happen", the optimizer can assume that
2153it occurs in dead code.
2154</p>
2155
2156<div class="doc_code">
2157<pre>
2158a: store undef -> %X
2159b: store %X -> undef
2160Safe:
2161a: &lt;deleted&gt;
2162b: unreachable
2163</pre>
2164</div>
2165
2166<p>These examples reiterate the fdiv example: a store "of" an undefined value
2167can be assumed to not have any effect: we can assume that the value is
2168overwritten with bits that happen to match what was already there. However, a
2169store "to" an undefined location could clobber arbitrary memory, therefore, it
2170has undefined behavior.</p>
2171
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2172</div>
2173
2174<!-- ======================================================================= -->
2175<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2176</div>
2177
2178<div class="doc_text">
2179
2180<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2181 to be used as constants. Constant expressions may be of
2182 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2183 operation that does not have side effects (e.g. load and call are not
2184 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2185
2186<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2187 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2188 <dd>Truncate a constant to another type. The bit size of CST must be larger
2189 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2190
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2191 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2192 <dd>Zero extend a constant to another type. The bit size of CST must be
2193 smaller or equal to the bit size of TYPE. Both types must be
2194 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2195
2196 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2197 <dd>Sign extend a constant to another type. The bit size of CST must be
2198 smaller or equal to the bit size of TYPE. Both types must be
2199 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2200
2201 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2202 <dd>Truncate a floating point constant to another floating point type. The
2203 size of CST must be larger than the size of TYPE. Both types must be
2204 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2205
2206 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2207 <dd>Floating point extend a constant to another type. The size of CST must be
2208 smaller or equal to the size of TYPE. Both types must be floating
2209 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2210
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2211 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2212 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2213 constant. TYPE must be a scalar or vector integer type. CST must be of
2214 scalar or vector floating point type. Both CST and TYPE must be scalars,
2215 or vectors of the same number of elements. If the value won't fit in the
2216 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2217
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2218 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2219 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2220 constant. TYPE must be a scalar or vector integer type. CST must be of
2221 scalar or vector floating point type. Both CST and TYPE must be scalars,
2222 or vectors of the same number of elements. If the value won't fit in the
2223 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2224
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2225 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2226 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2227 constant. TYPE must be a scalar or vector floating point type. CST must be
2228 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2229 vectors of the same number of elements. If the value won't fit in the
2230 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2231
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2232 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2233 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2234 constant. TYPE must be a scalar or vector floating point type. CST must be
2235 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2236 vectors of the same number of elements. If the value won't fit in the
2237 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2238
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2239 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2240 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2241 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2242 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2243 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2244
2245 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2246 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2247 type. CST must be of integer type. The CST value is zero extended,
2248 truncated, or unchanged to make it fit in a pointer size. This one is
2249 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2250
2251 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2252 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2253 are the same as those for the <a href="#i_bitcast">bitcast
2254 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2255
2256 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2257 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2258 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2259 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2260 instruction, the index list may have zero or more indexes, which are
2261 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2262
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2263 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2264 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2265
2266 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2267 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2268
2269 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2270 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2271
2272 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2273 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2274 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2275
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2276 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2277 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2278 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2279
2280 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2281 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2282 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2283
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2284 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2285 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2286 be any of the <a href="#binaryops">binary</a>
2287 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2288 on operands are the same as those for the corresponding instruction
2289 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2290</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2291
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2292</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2293
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2294<!-- ======================================================================= -->
2295<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2296</div>
2297
2298<div class="doc_text">
2299
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2300<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2301 stream without affecting the behaviour of the program. There are two
2302 metadata primitives, strings and nodes. All metadata has the
2303 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2304 point ('<tt>!</tt>').</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2305
2306<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2307 any character by escaping non-printable characters with "\xx" where "xx" is
2308 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2309
2310<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2311 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2312 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2313 10}</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2314
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2315<p>A metadata node will attempt to track changes to the values it holds. In the
2316 event that a value is deleted, it will be replaced with a typeless
2317 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckycb337992009-05-10 20:57:05 +0000[diff] [blame]2318
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2319<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2320 the program that isn't available in the instructions, or that isn't easily
2321 computable. Similarly, the code generator may expect a certain metadata
2322 format to be used to express debugging information.</p>
2323
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2324</div>
2325
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2326<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2327<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2328<!-- *********************************************************************** -->
2329
2330<!-- ======================================================================= -->
2331<div class="doc_subsection">
2332<a name="inlineasm">Inline Assembler Expressions</a>
2333</div>
2334
2335<div class="doc_text">
2336
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2337<p>LLVM supports inline assembler expressions (as opposed
2338 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2339 a special value. This value represents the inline assembler as a string
2340 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2341 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame^]2342 expression has side effects, and a flag indicating whether the function
2343 containing the asm needs to align its stack conservatively. An example
2344 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2345
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2346<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2347<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2348i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2349</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2350</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2352<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2353 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2354 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2355
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2356<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2357<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2358%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]2359</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2360</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2361
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2362<p>Inline asms with side effects not visible in the constraint list must be
2363 marked as having side effects. This is done through the use of the
2364 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2365
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2366<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2367<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2368call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2369</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2370</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2371
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame^]2372<p>In some cases inline asms will contain code that will not work unless the
2373 stack is aligned in some way, such as calls or SSE instructions on x86,
2374 yet will not contain code that does that alignment within the asm.
2375 The compiler should make conservative assumptions about what the asm might
2376 contain and should generate its usual stack alignment code in the prologue
2377 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2378
2379<div class="doc_code">
2380<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame^]2381call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2382</pre>
2383</div>
2384
2385<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2386 first.</p>
2387
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2388<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2389 documented here. Constraints on what can be done (e.g. duplication, moving,
2390 etc need to be documented). This is probably best done by reference to
2391 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2392
2393</div>
2394
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2395
2396<!-- *********************************************************************** -->
2397<div class="doc_section">
2398 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2399</div>
2400<!-- *********************************************************************** -->
2401
2402<p>LLVM has a number of "magic" global variables that contain data that affect
2403code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2404of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2405section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2406by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2407
2408<!-- ======================================================================= -->
2409<div class="doc_subsection">
2410<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2411</div>
2412
2413<div class="doc_text">
2414
2415<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2416href="#linkage_appending">appending linkage</a>. This array contains a list of
2417pointers to global variables and functions which may optionally have a pointer
2418cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2419
2420<pre>
2421 @X = global i8 4
2422 @Y = global i32 123
2423
2424 @llvm.used = appending global [2 x i8*] [
2425 i8* @X,
2426 i8* bitcast (i32* @Y to i8*)
2427 ], section "llvm.metadata"
2428</pre>
2429
2430<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2431compiler, assembler, and linker are required to treat the symbol as if there is
2432a reference to the global that it cannot see. For example, if a variable has
2433internal linkage and no references other than that from the <tt>@llvm.used</tt>
2434list, it cannot be deleted. This is commonly used to represent references from
2435inline asms and other things the compiler cannot "see", and corresponds to
2436"attribute((used))" in GNU C.</p>
2437
2438<p>On some targets, the code generator must emit a directive to the assembler or
2439object file to prevent the assembler and linker from molesting the symbol.</p>
2440
2441</div>
2442
2443<!-- ======================================================================= -->
2444<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2445<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2446</div>
2447
2448<div class="doc_text">
2449
2450<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2451<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2452touching the symbol. On targets that support it, this allows an intelligent
2453linker to optimize references to the symbol without being impeded as it would be
2454by <tt>@llvm.used</tt>.</p>
2455
2456<p>This is a rare construct that should only be used in rare circumstances, and
2457should not be exposed to source languages.</p>
2458
2459</div>
2460
2461<!-- ======================================================================= -->
2462<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2463<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2464</div>
2465
2466<div class="doc_text">
2467
2468<p>TODO: Describe this.</p>
2469
2470</div>
2471
2472<!-- ======================================================================= -->
2473<div class="doc_subsection">
2474<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2475</div>
2476
2477<div class="doc_text">
2478
2479<p>TODO: Describe this.</p>
2480
2481</div>
2482
2483
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2484<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2485<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2486<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2487
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2488<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2489
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2490<p>The LLVM instruction set consists of several different classifications of
2491 instructions: <a href="#terminators">terminator
2492 instructions</a>, <a href="#binaryops">binary instructions</a>,
2493 <a href="#bitwiseops">bitwise binary instructions</a>,
2494 <a href="#memoryops">memory instructions</a>, and
2495 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2496
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2497</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2498
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2499<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2500<div class="doc_subsection"> <a name="terminators">Terminator
2501Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2502
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2503<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2504
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2505<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2506 in a program ends with a "Terminator" instruction, which indicates which
2507 block should be executed after the current block is finished. These
2508 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2509 control flow, not values (the one exception being the
2510 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2511
2512<p>There are six different terminator instructions: the
2513 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2514 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2515 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2516 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2517 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2518 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2519
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2520</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2521
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2522<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2523<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2524Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2525
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2526<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2527
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2528<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2529<pre>
2530 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]2531 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2532</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2533
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2534<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2535<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2536 a value) from a function back to the caller.</p>
2537
2538<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2539 value and then causes control flow, and one that just causes control flow to
2540 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2541
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2542<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2543<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2544 return value. The type of the return value must be a
2545 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2546
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2547<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2548 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2549 value or a return value with a type that does not match its type, or if it
2550 has a void return type and contains a '<tt>ret</tt>' instruction with a
2551 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2552
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2553<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2554<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2555 the calling function's context. If the caller is a
2556 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2557 instruction after the call. If the caller was an
2558 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2559 the beginning of the "normal" destination block. If the instruction returns
2560 a value, that value shall set the call or invoke instruction's return
2561 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2562
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2563<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2564<pre>
2565 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2566 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2567 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]2568</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2569
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2570<p>Note that the code generator does not yet fully support large
2571 return values. The specific sizes that are currently supported are
2572 dependent on the target. For integers, on 32-bit targets the limit
2573 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2574 For aggregate types, the current limits are dependent on the element
2575 types; for example targets are often limited to 2 total integer
2576 elements and 2 total floating-point elements.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2577
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2578</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2579<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2580<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2581
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2582<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2583
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2584<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2585<pre>
2586 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]2587</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2589<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2590<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2591 different basic block in the current function. There are two forms of this
2592 instruction, corresponding to a conditional branch and an unconditional
2593 branch.</p>
2594
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2595<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2596<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2597 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2598 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2599 target.</p>
2600
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2601<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2602<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2603 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2604 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2605 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2606
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2607<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2608<pre>
2609Test:
2610 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2611 br i1 %cond, label %IfEqual, label %IfUnequal
2612IfEqual:
2613 <a href="#i_ret">ret</a> i32 1
2614IfUnequal:
2615 <a href="#i_ret">ret</a> i32 0
2616</pre>
2617
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2618</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2619
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2620<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2621<div class="doc_subsubsection">
2622 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2623</div>
2624
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2625<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2626
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2627<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2628<pre>
2629 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2630</pre>
2631
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2632<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2633<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]2634 several different places. It is a generalization of the '<tt>br</tt>'
2635 instruction, allowing a branch to occur to one of many possible
2636 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2637
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2638<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2639<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2640 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2641 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2642 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2643
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2644<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2645<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2646 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2647 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2648 transferred to the corresponding destination; otherwise, control flow is
2649 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2650
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2651<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2652<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2653 <tt>switch</tt> instruction, this instruction may be code generated in
2654 different ways. For example, it could be generated as a series of chained
2655 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2656
2657<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2658<pre>
2659 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2660 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2661 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2662
2663 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2664 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2665
2666 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2667 switch i32 %val, label %otherwise [ i32 0, label %onzero
2668 i32 1, label %onone
2669 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2670</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2671
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2672</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2673
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2674<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2675<div class="doc_subsubsection">
2676 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2677</div>
2678
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2679<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2680
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2681<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2682<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2683 &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]2684 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2685</pre>
2686
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2687<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2688<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2689 function, with the possibility of control flow transfer to either the
2690 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2691 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2692 control flow will return to the "normal" label. If the callee (or any
2693 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2694 instruction, control is interrupted and continued at the dynamically nearest
2695 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2696
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2697<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2698<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2699
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2700<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2701 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2702 convention</a> the call should use. If none is specified, the call
2703 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2704
2705 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2706 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2707 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2708
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2709 <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]2710 function value being invoked. In most cases, this is a direct function
2711 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2712 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2713
2714 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2715 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2716
2717 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2718 signature argument types. If the function signature indicates the
2719 function accepts a variable number of arguments, the extra arguments can
2720 be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2721
2722 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2723 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2724
2725 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2726 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2727
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2728 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2729 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2730 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2731</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2732
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2733<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2734<p>This instruction is designed to operate as a standard
2735 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2736 primary difference is that it establishes an association with a label, which
2737 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2738
2739<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2740 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2741 exception. Additionally, this is important for implementation of
2742 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2743
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2744<p>For the purposes of the SSA form, the definition of the value returned by the
2745 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2746 block to the "normal" label. If the callee unwinds then no return value is
2747 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]2748
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2749<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2750<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2751 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2752 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2753 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2754 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2755</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2756
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2757</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2758
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2759<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2760
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2761<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2762Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2763
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2764<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2765
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2766<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2767<pre>
2768 unwind
2769</pre>
2770
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2771<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2772<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2773 at the first callee in the dynamic call stack which used
2774 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2775 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2776
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2777<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2778<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2779 immediately halt. The dynamic call stack is then searched for the
2780 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2781 Once found, execution continues at the "exceptional" destination block
2782 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2783 instruction in the dynamic call chain, undefined behavior results.</p>
2784
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2785</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2786
2787<!-- _______________________________________________________________________ -->
2788
2789<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2790Instruction</a> </div>
2791
2792<div class="doc_text">
2793
2794<h5>Syntax:</h5>
2795<pre>
2796 unreachable
2797</pre>
2798
2799<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2800<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2801 instruction is used to inform the optimizer that a particular portion of the
2802 code is not reachable. This can be used to indicate that the code after a
2803 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2804
2805<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2806<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2807
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2808</div>
2809
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2810<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2811<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2812
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2813<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2814
2815<p>Binary operators are used to do most of the computation in a program. They
2816 require two operands of the same type, execute an operation on them, and
2817 produce a single value. The operands might represent multiple data, as is
2818 the case with the <a href="#t_vector">vector</a> data type. The result value
2819 has the same type as its operands.</p>
2820
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2821<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2822
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2823</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2825<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2826<div class="doc_subsubsection">
2827 <a name="i_add">'<tt>add</tt>' Instruction</a>
2828</div>
2829
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2830<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2831
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2832<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2833<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2834 &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]2835 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2836 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2837 &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]2838</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2839
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2840<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2841<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2842
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2843<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2844<p>The two arguments to the '<tt>add</tt>' instruction must
2845 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2846 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2847
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2848<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2849<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2850
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2851<p>If the sum has unsigned overflow, the result returned is the mathematical
2852 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]2853
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2854<p>Because LLVM integers use a two's complement representation, this instruction
2855 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2856
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2857<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2858 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2859 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2860 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2861
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2862<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2863<pre>
2864 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2865</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2866
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2867</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2868
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2869<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2870<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2871 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2872</div>
2873
2874<div class="doc_text">
2875
2876<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2877<pre>
2878 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2879</pre>
2880
2881<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2882<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2883
2884<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2885<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2886 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2887 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2888
2889<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2890<p>The value produced is the floating point sum of the two operands.</p>
2891
2892<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2893<pre>
2894 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2895</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2896
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2897</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2898
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2899<!-- _______________________________________________________________________ -->
2900<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2901 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2902</div>
2903
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2904<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2906<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2907<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2908 &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]2909 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2910 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2911 &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]2912</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2914<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2915<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2916 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2917
2918<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2919 '<tt>neg</tt>' instruction present in most other intermediate
2920 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2921
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2922<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2923<p>The two arguments to the '<tt>sub</tt>' instruction must
2924 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2925 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2926
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2927<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2928<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2929
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2930<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2931 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2932 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2933
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2934<p>Because LLVM integers use a two's complement representation, this instruction
2935 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2936
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2937<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2938 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2939 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2940 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2941
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2942<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2943<pre>
2944 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2945 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2946</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2947
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2948</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2949
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2950<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2951<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2952 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2953</div>
2954
2955<div class="doc_text">
2956
2957<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2958<pre>
2959 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2960</pre>
2961
2962<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2963<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2964 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2965
2966<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2967 '<tt>fneg</tt>' instruction present in most other intermediate
2968 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2969
2970<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2971<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2972 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2973 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2974
2975<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2976<p>The value produced is the floating point difference of the two operands.</p>
2977
2978<h5>Example:</h5>
2979<pre>
2980 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2981 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2982</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2983
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2984</div>
2985
2986<!-- _______________________________________________________________________ -->
2987<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2988 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2989</div>
2990
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2991<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2992
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2993<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2994<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2995 &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]2996 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2997 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2998 &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]2999</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3000
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3001<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3002<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3003
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3004<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3005<p>The two arguments to the '<tt>mul</tt>' instruction must
3006 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3007 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3008
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3009<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3010<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3011
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3012<p>If the result of the multiplication has unsigned overflow, the result
3013 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3014 width of the result.</p>
3015
3016<p>Because LLVM integers use a two's complement representation, and the result
3017 is the same width as the operands, this instruction returns the correct
3018 result for both signed and unsigned integers. If a full product
3019 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3020 be sign-extended or zero-extended as appropriate to the width of the full
3021 product.</p>
3022
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3023<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3024 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3025 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3026 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3027
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3028<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3029<pre>
3030 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3031</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3032
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3033</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3034
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3035<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3036<div class="doc_subsubsection">
3037 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3038</div>
3039
3040<div class="doc_text">
3041
3042<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3043<pre>
3044 &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]3045</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3046
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3047<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3048<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3049
3050<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3051<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3052 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3053 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3054
3055<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3056<p>The value produced is the floating point product of the two operands.</p>
3057
3058<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3059<pre>
3060 &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]3061</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3062
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3063</div>
3064
3065<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3066<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3067</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3068
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3069<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3070
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3071<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3072<pre>
3073 &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]3074</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3075
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3076<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3077<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3078
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3079<h5>Arguments:</h5>
3080<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3081 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3082 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3083
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3084<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3085<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3086
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3087<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3088 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3089
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3090<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3091
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3092<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3093<pre>
3094 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3095</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3096
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3097</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3098
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3099<!-- _______________________________________________________________________ -->
3100<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3101</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3102
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3103<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3104
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3105<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3106<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3107 &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]3108 &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]3109</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3110
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3111<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3112<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3113
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3114<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3115<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3116 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3117 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3118
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3119<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3120<p>The value produced is the signed integer quotient of the two operands rounded
3121 towards zero.</p>
3122
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3123<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3124 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3125
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3126<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3127 undefined behavior; this is a rare case, but can occur, for example, by doing
3128 a 32-bit division of -2147483648 by -1.</p>
3129
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3130<p>If the <tt>exact</tt> keyword is present, the result value of the
3131 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3132 would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3133
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3134<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3135<pre>
3136 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3137</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3138
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3139</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3140
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3141<!-- _______________________________________________________________________ -->
3142<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3143Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3144
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3145<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3146
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3147<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3148<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3149 &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]3150</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3151
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152<h5>Overview:</h5>
3153<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3154
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3155<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3156<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3157 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3158 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3159
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3160<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3161<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3162
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3163<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3164<pre>
3165 &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]3166</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3167
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3168</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3169
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3170<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3171<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3172</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3173
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3174<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3175
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3176<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3177<pre>
3178 &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]3179</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3180
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3181<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3182<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3183 division of its two arguments.</p>
3184
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3185<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3186<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3187 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3188 values. Both arguments must have identical types.</p>
3189
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3190<h5>Semantics:</h5>
3191<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3192 This instruction always performs an unsigned division to get the
3193 remainder.</p>
3194
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3195<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3196 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3197
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3198<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3199
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3200<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3201<pre>
3202 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3203</pre>
3204
3205</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3206
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3207<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3208<div class="doc_subsubsection">
3209 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3210</div>
3211
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3212<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3213
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3214<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3215<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3216 &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]3217</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3218
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3219<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3220<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3221 division of its two operands. This instruction can also take
3222 <a href="#t_vector">vector</a> versions of the values in which case the
3223 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3224
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3225<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3226<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3227 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3228 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3229
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3230<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3231<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3232 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3233 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3234 a value. For more information about the difference,
3235 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3236 Math Forum</a>. For a table of how this is implemented in various languages,
3237 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3238 Wikipedia: modulo operation</a>.</p>
3239
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3240<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3241 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3242
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3243<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3244 Overflow also leads to undefined behavior; this is a rare case, but can
3245 occur, for example, by taking the remainder of a 32-bit division of
3246 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3247 lets srem be implemented using instructions that return both the result of
3248 the division and the remainder.)</p>
3249
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3250<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3251<pre>
3252 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3253</pre>
3254
3255</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3256
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3257<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3258<div class="doc_subsubsection">
3259 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3260
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3261<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3262
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3263<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3264<pre>
3265 &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]3266</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3267
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3268<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3269<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3270 its two operands.</p>
3271
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3272<h5>Arguments:</h5>
3273<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3274 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3275 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3276
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3277<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3278<p>This instruction returns the <i>remainder</i> of a division. The remainder
3279 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3280
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3281<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3282<pre>
3283 &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]3284</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3285
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3286</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3287
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3288<!-- ======================================================================= -->
3289<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3290Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3291
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3292<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3293
3294<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3295 program. They are generally very efficient instructions and can commonly be
3296 strength reduced from other instructions. They require two operands of the
3297 same type, execute an operation on them, and produce a single value. The
3298 resulting value is the same type as its operands.</p>
3299
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3300</div>
3301
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3302<!-- _______________________________________________________________________ -->
3303<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3304Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3305
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3306<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3307
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3308<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3309<pre>
3310 &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]3311</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3312
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3313<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3314<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3315 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3316
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3317<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3318<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3319 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3320 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3321
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3322<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3323<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3324 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3325 is (statically or dynamically) negative or equal to or larger than the number
3326 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3327 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3328 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3329
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3330<h5>Example:</h5>
3331<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3332 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3333 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3334 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3335 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3336 &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]3337</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3338
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3339</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3340
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3341<!-- _______________________________________________________________________ -->
3342<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3343Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3344
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3345<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3346
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3347<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3348<pre>
3349 &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]3350</pre>
3351
3352<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3353<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3354 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3355
3356<h5>Arguments:</h5>
3357<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3358 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3359 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3360
3361<h5>Semantics:</h5>
3362<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3363 significant bits of the result will be filled with zero bits after the shift.
3364 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3365 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3366 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3367 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3368
3369<h5>Example:</h5>
3370<pre>
3371 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3372 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3373 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3374 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3375 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3376 &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]3377</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3378
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3379</div>
3380
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3381<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3382<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3383Instruction</a> </div>
3384<div class="doc_text">
3385
3386<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3387<pre>
3388 &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]3389</pre>
3390
3391<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3392<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3393 operand shifted to the right a specified number of bits with sign
3394 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3395
3396<h5>Arguments:</h5>
3397<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3398 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3399 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3400
3401<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3402<p>This instruction always performs an arithmetic shift right operation, The
3403 most significant bits of the result will be filled with the sign bit
3404 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3405 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3406 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3407 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3408
3409<h5>Example:</h5>
3410<pre>
3411 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3412 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3413 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3414 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3415 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3416 &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]3417</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3418
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3419</div>
3420
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3421<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3422<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3423Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3424
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3425<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3426
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3427<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3428<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3429 &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]3430</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3431
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3432<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3433<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3434 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3435
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3436<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3437<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3438 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3439 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3440
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3441<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3442<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3443
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3444<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3445 <tbody>
3446 <tr>
3447 <td>In0</td>
3448 <td>In1</td>
3449 <td>Out</td>
3450 </tr>
3451 <tr>
3452 <td>0</td>
3453 <td>0</td>
3454 <td>0</td>
3455 </tr>
3456 <tr>
3457 <td>0</td>
3458 <td>1</td>
3459 <td>0</td>
3460 </tr>
3461 <tr>
3462 <td>1</td>
3463 <td>0</td>
3464 <td>0</td>
3465 </tr>
3466 <tr>
3467 <td>1</td>
3468 <td>1</td>
3469 <td>1</td>
3470 </tr>
3471 </tbody>
3472</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3473
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3474<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3475<pre>
3476 &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]3477 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3478 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3479</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3480</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3481<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3482<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3483
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3484<div class="doc_text">
3485
3486<h5>Syntax:</h5>
3487<pre>
3488 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3489</pre>
3490
3491<h5>Overview:</h5>
3492<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3493 two operands.</p>
3494
3495<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3496<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3497 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3498 values. Both arguments must have identical types.</p>
3499
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3500<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3501<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3502
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3503<table border="1" cellspacing="0" cellpadding="4">
3504 <tbody>
3505 <tr>
3506 <td>In0</td>
3507 <td>In1</td>
3508 <td>Out</td>
3509 </tr>
3510 <tr>
3511 <td>0</td>
3512 <td>0</td>
3513 <td>0</td>
3514 </tr>
3515 <tr>
3516 <td>0</td>
3517 <td>1</td>
3518 <td>1</td>
3519 </tr>
3520 <tr>
3521 <td>1</td>
3522 <td>0</td>
3523 <td>1</td>
3524 </tr>
3525 <tr>
3526 <td>1</td>
3527 <td>1</td>
3528 <td>1</td>
3529 </tr>
3530 </tbody>
3531</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3532
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3533<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3534<pre>
3535 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3536 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3537 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3538</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3539
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3540</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3541
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3542<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3543<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3544Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3545
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3546<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3547
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3548<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3549<pre>
3550 &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]3551</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3552
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3553<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3554<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3555 its two operands. The <tt>xor</tt> is used to implement the "one's
3556 complement" operation, which is the "~" operator in C.</p>
3557
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3558<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3559<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3560 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3561 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3562
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3563<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3564<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3565
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3566<table border="1" cellspacing="0" cellpadding="4">
3567 <tbody>
3568 <tr>
3569 <td>In0</td>
3570 <td>In1</td>
3571 <td>Out</td>
3572 </tr>
3573 <tr>
3574 <td>0</td>
3575 <td>0</td>
3576 <td>0</td>
3577 </tr>
3578 <tr>
3579 <td>0</td>
3580 <td>1</td>
3581 <td>1</td>
3582 </tr>
3583 <tr>
3584 <td>1</td>
3585 <td>0</td>
3586 <td>1</td>
3587 </tr>
3588 <tr>
3589 <td>1</td>
3590 <td>1</td>
3591 <td>0</td>
3592 </tr>
3593 </tbody>
3594</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3595
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3596<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3597<pre>
3598 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3599 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3600 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3601 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3602</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3603
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3604</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3605
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3606<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3607<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3608 <a name="vectorops">Vector Operations</a>
3609</div>
3610
3611<div class="doc_text">
3612
3613<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3614 target-independent manner. These instructions cover the element-access and
3615 vector-specific operations needed to process vectors effectively. While LLVM
3616 does directly support these vector operations, many sophisticated algorithms
3617 will want to use target-specific intrinsics to take full advantage of a
3618 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3619
3620</div>
3621
3622<!-- _______________________________________________________________________ -->
3623<div class="doc_subsubsection">
3624 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3625</div>
3626
3627<div class="doc_text">
3628
3629<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3630<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3631 &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]3632</pre>
3633
3634<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3635<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3636 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3637
3638
3639<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3640<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3641 of <a href="#t_vector">vector</a> type. The second operand is an index
3642 indicating the position from which to extract the element. The index may be
3643 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3644
3645<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3646<p>The result is a scalar of the same type as the element type of
3647 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3648 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3649 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3650
3651<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3652<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3653 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3654</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3655
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3656</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3657
3658<!-- _______________________________________________________________________ -->
3659<div class="doc_subsubsection">
3660 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3661</div>
3662
3663<div class="doc_text">
3664
3665<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3666<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]3667 &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]3668</pre>
3669
3670<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3671<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3672 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3673
3674<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3675<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3676 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3677 whose type must equal the element type of the first operand. The third
3678 operand is an index indicating the position at which to insert the value.
3679 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3680
3681<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3682<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3683 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3684 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3685 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3686
3687<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3688<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3689 %result = 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]3690</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3691
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3692</div>
3693
3694<!-- _______________________________________________________________________ -->
3695<div class="doc_subsubsection">
3696 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3697</div>
3698
3699<div class="doc_text">
3700
3701<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3702<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3703 &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]3704</pre>
3705
3706<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3707<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3708 from two input vectors, returning a vector with the same element type as the
3709 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3710
3711<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3712<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3713 with types that match each other. The third argument is a shuffle mask whose
3714 element type is always 'i32'. The result of the instruction is a vector
3715 whose length is the same as the shuffle mask and whose element type is the
3716 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3717
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3718<p>The shuffle mask operand is required to be a constant vector with either
3719 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3720
3721<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3722<p>The elements of the two input vectors are numbered from left to right across
3723 both of the vectors. The shuffle mask operand specifies, for each element of
3724 the result vector, which element of the two input vectors the result element
3725 gets. The element selector may be undef (meaning "don't care") and the
3726 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3727
3728<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3729<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3730 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3731 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3732 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3733 &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.
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3734 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3735 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3736 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3737 &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]3738</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3739
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3740</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]3741
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3742<!-- ======================================================================= -->
3743<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3744 <a name="aggregateops">Aggregate Operations</a>
3745</div>
3746
3747<div class="doc_text">
3748
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3749<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3750
3751</div>
3752
3753<!-- _______________________________________________________________________ -->
3754<div class="doc_subsubsection">
3755 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3756</div>
3757
3758<div class="doc_text">
3759
3760<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3761<pre>
3762 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3763</pre>
3764
3765<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3766<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3767 or array element from an aggregate value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3768
3769<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3770<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3771 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3772 operands are constant indices to specify which value to extract in a similar
3773 manner as indices in a
3774 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3775
3776<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3777<p>The result is the value at the position in the aggregate specified by the
3778 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3779
3780<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3781<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3782 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3783</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3784
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3785</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3786
3787<!-- _______________________________________________________________________ -->
3788<div class="doc_subsubsection">
3789 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3790</div>
3791
3792<div class="doc_text">
3793
3794<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3795<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3796 &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]3797</pre>
3798
3799<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3800<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3801 array element in an aggregate.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3802
3803
3804<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3805<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3806 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3807 second operand is a first-class value to insert. The following operands are
3808 constant indices indicating the position at which to insert the value in a
3809 similar manner as indices in a
3810 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3811 value to insert must have the same type as the value identified by the
3812 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3813
3814<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3815<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3816 that of <tt>val</tt> except that the value at the position specified by the
3817 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3818
3819<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3820<pre>
Dan Gohman52bb2db2008-06-23 15:26:37 +0000[diff] [blame]3821 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3822</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3823
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3824</div>
3825
3826
3827<!-- ======================================================================= -->
3828<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3829 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3830</div>
3831
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3832<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3833
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3834<p>A key design point of an SSA-based representation is how it represents
3835 memory. In LLVM, no memory locations are in SSA form, which makes things
3836 very simple. This section describes how to read, write, allocate, and free
3837 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3838
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3839</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3840
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3841<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3842<div class="doc_subsubsection">
3843 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3844</div>
3845
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3846<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3847
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3848<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3849<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3850 &lt;result&gt; = malloc &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]3851</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3852
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3853<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3854<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3855 returns a pointer to it. The object is always allocated in the generic
3856 address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3857
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3858<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3859<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3860 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3861 system and returns a pointer of the appropriate type to the program. If
3862 "NumElements" is specified, it is the number of elements allocated, otherwise
3863 "NumElements" is defaulted to be one. If a constant alignment is specified,
3864 the value result of the allocation is guaranteed to be aligned to at least
3865 that boundary. If not specified, or if zero, the target can choose to align
3866 the allocation on any convenient boundary compatible with the type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3867
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3868<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3869
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3870<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3871<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3872 pointer is returned. The result of a zero byte allocation is undefined. The
3873 result is null if there is insufficient memory available.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3874
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3875<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3876<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3877 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3878
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3879 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3880 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3881 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3882 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3883 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3884</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3885
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3886<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3887
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3888</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3889
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3890<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3891<div class="doc_subsubsection">
3892 <a name="i_free">'<tt>free</tt>' Instruction</a>
3893</div>
3894
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3895<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3896
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3897<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3898<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3899 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3900</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3901
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3902<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3903<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3904 to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3906<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3907<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3908 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3909
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3910<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3911<p>Access to the memory pointed to by the pointer is no longer defined after
3912 this instruction executes. If the pointer is null, the operation is a
3913 noop.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3914
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3915<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3916<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3917 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3918 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3919</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3920
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3921</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3922
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3923<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3924<div class="doc_subsubsection">
3925 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3926</div>
3927
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3928<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3929
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3930<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3931<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3932 &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]3933</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3934
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3935<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3936<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3937 currently executing function, to be automatically released when this function
3938 returns to its caller. The object is always allocated in the generic address
3939 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3940
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3941<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3942<p>The '<tt>alloca</tt>' instruction
3943 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3944 runtime stack, returning a pointer of the appropriate type to the program.
3945 If "NumElements" is specified, it is the number of elements allocated,
3946 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3947 specified, the value result of the allocation is guaranteed to be aligned to
3948 at least that boundary. If not specified, or if zero, the target can choose
3949 to align the allocation on any convenient boundary compatible with the
3950 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3951
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3952<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3953
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3954<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]3955<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3956 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3957 memory is automatically released when the function returns. The
3958 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3959 variables that must have an address available. When the function returns
3960 (either with the <tt><a href="#i_ret">ret</a></tt>
3961 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3962 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3963
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3964<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3965<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3966 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3967 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3968 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3969 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3970</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3971
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3972</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3973
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3974<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3975<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3976Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3977
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3978<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3979
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3980<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3981<pre>
3982 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3983 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3984</pre>
3985
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3986<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3987<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3988
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3989<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3990<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3991 from which to load. The pointer must point to
3992 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3993 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3994 number or order of execution of this <tt>load</tt> with other
3995 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3996 instructions. </p>
3997
3998<p>The optional constant "align" argument specifies the alignment of the
3999 operation (that is, the alignment of the memory address). A value of 0 or an
4000 omitted "align" argument means that the operation has the preferential
4001 alignment for the target. It is the responsibility of the code emitter to
4002 ensure that the alignment information is correct. Overestimating the
4003 alignment results in an undefined behavior. Underestimating the alignment may
4004 produce less efficient code. An alignment of 1 is always safe.</p>
4005
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4006<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4007<p>The location of memory pointed to is loaded. If the value being loaded is of
4008 scalar type then the number of bytes read does not exceed the minimum number
4009 of bytes needed to hold all bits of the type. For example, loading an
4010 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4011 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4012 is undefined if the value was not originally written using a store of the
4013 same type.</p>
4014
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4015<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4016<pre>
4017 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4018 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4019 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4020</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4021
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4022</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4023
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4024<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4025<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4026Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4027
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4028<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4029
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4030<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4031<pre>
4032 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]4033 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]4034</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4035
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4036<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4037<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4038
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4039<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4040<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4041 and an address at which to store it. The type of the
4042 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4043 the <a href="#t_firstclass">first class</a> type of the
4044 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4045 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4046 or order of execution of this <tt>store</tt> with other
4047 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4048 instructions.</p>
4049
4050<p>The optional constant "align" argument specifies the alignment of the
4051 operation (that is, the alignment of the memory address). A value of 0 or an
4052 omitted "align" argument means that the operation has the preferential
4053 alignment for the target. It is the responsibility of the code emitter to
4054 ensure that the alignment information is correct. Overestimating the
4055 alignment results in an undefined behavior. Underestimating the alignment may
4056 produce less efficient code. An alignment of 1 is always safe.</p>
4057
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4058<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4059<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4060 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4061 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4062 does not exceed the minimum number of bytes needed to hold all bits of the
4063 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4064 writing a value of a type like <tt>i20</tt> with a size that is not an
4065 integral number of bytes, it is unspecified what happens to the extra bits
4066 that do not belong to the type, but they will typically be overwritten.</p>
4067
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4068<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4069<pre>
4070 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4071 store i32 3, i32* %ptr <i>; yields {void}</i>
4072 %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]4073</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4074
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4075</div>
4076
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4077<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4078<div class="doc_subsubsection">
4079 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4080</div>
4081
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4082<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4083
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4084<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4085<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4086 &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]4087 &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]4088</pre>
4089
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4090<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4091<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4092 subelement of an aggregate data structure. It performs address calculation
4093 only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4094
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4095<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4096<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4097 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4098 elements of the aggregate object are indexed. The interpretation of each
4099 index is dependent on the type being indexed into. The first index always
4100 indexes the pointer value given as the first argument, the second index
4101 indexes a value of the type pointed to (not necessarily the value directly
4102 pointed to, since the first index can be non-zero), etc. The first type
4103 indexed into must be a pointer value, subsequent types can be arrays, vectors
4104 and structs. Note that subsequent types being indexed into can never be
4105 pointers, since that would require loading the pointer before continuing
4106 calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4107
4108<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]4109 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4110 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4111 vector, integers of any width are allowed, and they are not required to be
4112 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4113
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4114<p>For example, let's consider a C code fragment and how it gets compiled to
4115 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4116
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4117<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4118<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4119struct RT {
4120 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4121 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4122 char C;
4123};
4124struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4125 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4126 double Y;
4127 struct RT Z;
4128};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4129
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4130int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4131 return &amp;s[1].Z.B[5][13];
4132}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4133</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4134</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4135
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4136<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4137
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4138<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4139<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4140%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4141%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4142
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4143define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4144entry:
4145 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4146 ret i32* %reg
4147}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4148</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4149</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4150
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4151<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4152<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]4153 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4154 }</tt>' type, a structure. The second index indexes into the third element
4155 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4156 i8 }</tt>' type, another structure. The third index indexes into the second
4157 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4158 array. The two dimensions of the array are subscripted into, yielding an
4159 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4160 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4161
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4162<p>Note that it is perfectly legal to index partially through a structure,
4163 returning a pointer to an inner element. Because of this, the LLVM code for
4164 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4165
4166<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4167 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4168 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4169 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4170 %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]4171 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4172 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4173 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4174 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4175</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4176
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4177<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4178 <tt>getelementptr</tt> is undefined if the base pointer is not an
4179 <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]4180 that would be formed by successive addition of the offsets implied by the
4181 indices to the base address with infinitely precise arithmetic are not an
4182 <i>in bounds</i> address of that allocated object.
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4183 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4184 that point into the object, plus the address one byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4185
4186<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4187 the base address with silently-wrapping two's complement arithmetic, and
4188 the result value of the <tt>getelementptr</tt> may be outside the object
4189 pointed to by the base pointer. The result value may not necessarily be
4190 used to access memory though, even if it happens to point into allocated
4191 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4192 section for more information.</p>
4193
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4194<p>The getelementptr instruction is often confusing. For some more insight into
4195 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4196
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4197<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4198<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4199 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4200 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4201 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4202 %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]4203 <i>; yields i8*:eptr</i>
4204 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4205 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4206 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4207</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4208
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4209</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4210
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4211<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4212<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4213</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4214
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4215<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4216
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4217<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4218 which all take a single operand and a type. They perform various bit
4219 conversions on the operand.</p>
4220
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4221</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4222
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4223<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4224<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4225 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4226</div>
4227<div class="doc_text">
4228
4229<h5>Syntax:</h5>
4230<pre>
4231 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4232</pre>
4233
4234<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4235<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4236 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4237
4238<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4239<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4240 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4241 size and type of the result, which must be
4242 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4243 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4244 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4245
4246<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4247<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4248 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4249 source size must be larger than the destination size, <tt>trunc</tt> cannot
4250 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4251
4252<h5>Example:</h5>
4253<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4254 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4255 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4256 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4257</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4258
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4259</div>
4260
4261<!-- _______________________________________________________________________ -->
4262<div class="doc_subsubsection">
4263 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4264</div>
4265<div class="doc_text">
4266
4267<h5>Syntax:</h5>
4268<pre>
4269 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4270</pre>
4271
4272<h5>Overview:</h5>
4273<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4274 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4275
4276
4277<h5>Arguments:</h5>
4278<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]4279 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4280 also be of <a href="#t_integer">integer</a> type. The bit size of the
4281 <tt>value</tt> must be smaller than the bit size of the destination type,
4282 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4283
4284<h5>Semantics:</h5>
4285<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]4286 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4287
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4288<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]4289
4290<h5>Example:</h5>
4291<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4292 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4293 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4294</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4295
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4296</div>
4297
4298<!-- _______________________________________________________________________ -->
4299<div class="doc_subsubsection">
4300 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4301</div>
4302<div class="doc_text">
4303
4304<h5>Syntax:</h5>
4305<pre>
4306 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4307</pre>
4308
4309<h5>Overview:</h5>
4310<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4311
4312<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4313<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4314 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4315 also be of <a href="#t_integer">integer</a> type. The bit size of the
4316 <tt>value</tt> must be smaller than the bit size of the destination type,
4317 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4318
4319<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4320<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4321 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4322 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4323
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4324<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]4325
4326<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4327<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4328 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4329 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4330</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4331
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4332</div>
4333
4334<!-- _______________________________________________________________________ -->
4335<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4336 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4337</div>
4338
4339<div class="doc_text">
4340
4341<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4342<pre>
4343 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4344</pre>
4345
4346<h5>Overview:</h5>
4347<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4348 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4349
4350<h5>Arguments:</h5>
4351<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4352 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4353 to cast it to. The size of <tt>value</tt> must be larger than the size of
4354 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4355 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4356
4357<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4358<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4359 <a href="#t_floating">floating point</a> type to a smaller
4360 <a href="#t_floating">floating point</a> type. If the value cannot fit
4361 within the destination type, <tt>ty2</tt>, then the results are
4362 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4363
4364<h5>Example:</h5>
4365<pre>
4366 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4367 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4368</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4369
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4370</div>
4371
4372<!-- _______________________________________________________________________ -->
4373<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4374 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4375</div>
4376<div class="doc_text">
4377
4378<h5>Syntax:</h5>
4379<pre>
4380 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4381</pre>
4382
4383<h5>Overview:</h5>
4384<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]4385 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4386
4387<h5>Arguments:</h5>
4388<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4389 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4390 a <a href="#t_floating">floating point</a> type to cast it to. The source
4391 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4392
4393<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4394<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4395 <a href="#t_floating">floating point</a> type to a larger
4396 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4397 used to make a <i>no-op cast</i> because it always changes bits. Use
4398 <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]4399
4400<h5>Example:</h5>
4401<pre>
4402 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4403 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4404</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4405
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4406</div>
4407
4408<!-- _______________________________________________________________________ -->
4409<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4410 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4411</div>
4412<div class="doc_text">
4413
4414<h5>Syntax:</h5>
4415<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4416 &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]4417</pre>
4418
4419<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4420<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4421 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4422
4423<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4424<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4425 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4426 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4427 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4428 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4429
4430<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4431<p>The '<tt>fptoui</tt>' instruction converts its
4432 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4433 towards zero) unsigned integer value. If the value cannot fit
4434 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4435
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4436<h5>Example:</h5>
4437<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4438 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4439 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4440 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4441</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4442
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4443</div>
4444
4445<!-- _______________________________________________________________________ -->
4446<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4447 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4448</div>
4449<div class="doc_text">
4450
4451<h5>Syntax:</h5>
4452<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4453 &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]4454</pre>
4455
4456<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4457<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4458 <a href="#t_floating">floating point</a> <tt>value</tt> to
4459 type <tt>ty2</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>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4462<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4463 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4464 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4465 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4466 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4467
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4468<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4469<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4470 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4471 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4472 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4473
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4474<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4475<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4476 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4477 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4478 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4479</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4480
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4481</div>
4482
4483<!-- _______________________________________________________________________ -->
4484<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4485 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4486</div>
4487<div class="doc_text">
4488
4489<h5>Syntax:</h5>
4490<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4491 &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]4492</pre>
4493
4494<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4495<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4496 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4497
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4498<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4499<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]4500 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4501 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4502 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4503 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4504
4505<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4506<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4507 integer quantity and converts it to the corresponding floating point
4508 value. If the value cannot fit in the floating point value, the results are
4509 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4510
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4511<h5>Example:</h5>
4512<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4513 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4514 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4515</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4516
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4517</div>
4518
4519<!-- _______________________________________________________________________ -->
4520<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4521 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4522</div>
4523<div class="doc_text">
4524
4525<h5>Syntax:</h5>
4526<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4527 &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]4528</pre>
4529
4530<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4531<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4532 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4533
4534<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4535<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]4536 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4537 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4538 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4539 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4540
4541<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4542<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4543 quantity and converts it to the corresponding floating point value. If the
4544 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4545
4546<h5>Example:</h5>
4547<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4548 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4549 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4550</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4551
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4552</div>
4553
4554<!-- _______________________________________________________________________ -->
4555<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4556 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4557</div>
4558<div class="doc_text">
4559
4560<h5>Syntax:</h5>
4561<pre>
4562 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4563</pre>
4564
4565<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4566<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4567 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4568
4569<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4570<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4571 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4572 <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]4573
4574<h5>Semantics:</h5>
4575<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4576 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4577 truncating or zero extending that value to the size of the integer type. If
4578 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4579 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4580 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4581 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4582
4583<h5>Example:</h5>
4584<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4585 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4586 %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]4587</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4588
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4589</div>
4590
4591<!-- _______________________________________________________________________ -->
4592<div class="doc_subsubsection">
4593 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4594</div>
4595<div class="doc_text">
4596
4597<h5>Syntax:</h5>
4598<pre>
4599 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4600</pre>
4601
4602<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4603<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4604 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4605
4606<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4607<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4608 value to cast, and a type to cast it to, which must be a
4609 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4610
4611<h5>Semantics:</h5>
4612<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4613 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4614 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4615 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4616 than the size of a pointer then a zero extension is done. If they are the
4617 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4618
4619<h5>Example:</h5>
4620<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4621 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4622 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4623 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4624</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4625
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4626</div>
4627
4628<!-- _______________________________________________________________________ -->
4629<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4630 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4631</div>
4632<div class="doc_text">
4633
4634<h5>Syntax:</h5>
4635<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4636 &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]4637</pre>
4638
4639<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4640<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4641 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4642
4643<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4644<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4645 non-aggregate first class value, and a type to cast it to, which must also be
4646 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4647 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4648 identical. If the source type is a pointer, the destination type must also be
4649 a pointer. This instruction supports bitwise conversion of vectors to
4650 integers and to vectors of other types (as long as they have the same
4651 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4652
4653<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4654<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4655 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4656 this conversion. The conversion is done as if the <tt>value</tt> had been
4657 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4658 be converted to other pointer types with this instruction. To convert
4659 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4660 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4661
4662<h5>Example:</h5>
4663<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4664 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4665 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4666 %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]4667</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4668
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4669</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4670
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4671<!-- ======================================================================= -->
4672<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4673
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4674<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4675
4676<p>The instructions in this category are the "miscellaneous" instructions, which
4677 defy better classification.</p>
4678
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4679</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4680
4681<!-- _______________________________________________________________________ -->
4682<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4683</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4684
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4685<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4686
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4687<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4688<pre>
4689 &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]4690</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4691
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4692<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4693<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4694 boolean values based on comparison of its two integer, integer vector, or
4695 pointer operands.</p>
4696
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4697<h5>Arguments:</h5>
4698<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4699 the condition code indicating the kind of comparison to perform. It is not a
4700 value, just a keyword. The possible condition code are:</p>
4701
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4702<ol>
4703 <li><tt>eq</tt>: equal</li>
4704 <li><tt>ne</tt>: not equal </li>
4705 <li><tt>ugt</tt>: unsigned greater than</li>
4706 <li><tt>uge</tt>: unsigned greater or equal</li>
4707 <li><tt>ult</tt>: unsigned less than</li>
4708 <li><tt>ule</tt>: unsigned less or equal</li>
4709 <li><tt>sgt</tt>: signed greater than</li>
4710 <li><tt>sge</tt>: signed greater or equal</li>
4711 <li><tt>slt</tt>: signed less than</li>
4712 <li><tt>sle</tt>: signed less or equal</li>
4713</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4714
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4715<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4716 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4717 typed. They must also be identical types.</p>
4718
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4719<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4720<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4721 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4722 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]4723 result, as follows:</p>
4724
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4725<ol>
4726 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4727 <tt>false</tt> otherwise. No sign interpretation is necessary or
4728 performed.</li>
4729
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4730 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4731 <tt>false</tt> otherwise. No sign interpretation is necessary or
4732 performed.</li>
4733
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4734 <li><tt>ugt</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 greater than <tt>op2</tt>.</li>
4736
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4737 <li><tt>uge</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 greater than or equal
4739 to <tt>op2</tt>.</li>
4740
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4741 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4742 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4743
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4744 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4745 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4746
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4747 <li><tt>sgt</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 greater than <tt>op2</tt>.</li>
4749
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4750 <li><tt>sge</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 greater than or equal
4752 to <tt>op2</tt>.</li>
4753
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4754 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4755 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4756
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4757 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4758 <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]4759</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4760
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4761<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4762 values are compared as if they were integers.</p>
4763
4764<p>If the operands are integer vectors, then they are compared element by
4765 element. The result is an <tt>i1</tt> vector with the same number of elements
4766 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4767
4768<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4769<pre>
4770 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4771 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4772 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4773 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4774 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4775 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4776</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4777
4778<p>Note that the code generator does not yet support vector types with
4779 the <tt>icmp</tt> instruction.</p>
4780
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4781</div>
4782
4783<!-- _______________________________________________________________________ -->
4784<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4785</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4786
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4787<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4788
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4789<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4790<pre>
4791 &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]4792</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4793
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4794<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4795<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4796 values based on comparison of its operands.</p>
4797
4798<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]4799(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4800
4801<p>If the operands are floating point vectors, then the result type is a vector
4802 of boolean with the same number of elements as the operands being
4803 compared.</p>
4804
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4805<h5>Arguments:</h5>
4806<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4807 the condition code indicating the kind of comparison to perform. It is not a
4808 value, just a keyword. The possible condition code are:</p>
4809
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4810<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4811 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4812 <li><tt>oeq</tt>: ordered and equal</li>
4813 <li><tt>ogt</tt>: ordered and greater than </li>
4814 <li><tt>oge</tt>: ordered and greater than or equal</li>
4815 <li><tt>olt</tt>: ordered and less than </li>
4816 <li><tt>ole</tt>: ordered and less than or equal</li>
4817 <li><tt>one</tt>: ordered and not equal</li>
4818 <li><tt>ord</tt>: ordered (no nans)</li>
4819 <li><tt>ueq</tt>: unordered or equal</li>
4820 <li><tt>ugt</tt>: unordered or greater than </li>
4821 <li><tt>uge</tt>: unordered or greater than or equal</li>
4822 <li><tt>ult</tt>: unordered or less than </li>
4823 <li><tt>ule</tt>: unordered or less than or equal</li>
4824 <li><tt>une</tt>: unordered or not equal</li>
4825 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4826 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4827</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4828
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4829<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4830 <i>unordered</i> means that either operand may be a QNAN.</p>
4831
4832<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4833 a <a href="#t_floating">floating point</a> type or
4834 a <a href="#t_vector">vector</a> of floating point type. They must have
4835 identical types.</p>
4836
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4837<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4838<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4839 according to the condition code given as <tt>cond</tt>. If the operands are
4840 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4841 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4842 follows:</p>
4843
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4844<ol>
4845 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4846
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4847 <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]4848 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4849
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4850 <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]4851 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4852
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4853 <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]4854 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4855
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4856 <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]4857 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4858
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4859 <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]4860 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4861
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4862 <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]4863 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4864
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4865 <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]4866
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4867 <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]4868 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4869
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4870 <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]4871 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4872
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4873 <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]4874 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4875
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4876 <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]4877 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4878
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4879 <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]4880 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4881
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4882 <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]4883 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4884
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4885 <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]4886
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4887 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4888</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4889
4890<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4891<pre>
4892 &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]4893 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4894 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4895 &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]4896</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4897
4898<p>Note that the code generator does not yet support vector types with
4899 the <tt>fcmp</tt> instruction.</p>
4900
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4901</div>
4902
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4903<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]4904<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4905 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4906</div>
4907
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4908<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4909
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4910<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4911<pre>
4912 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4913</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4914
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4915<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4916<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4917 SSA graph representing the function.</p>
4918
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4919<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4920<p>The type of the incoming values is specified with the first type field. After
4921 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4922 one pair for each predecessor basic block of the current block. Only values
4923 of <a href="#t_firstclass">first class</a> type may be used as the value
4924 arguments to the PHI node. Only labels may be used as the label
4925 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4926
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4927<p>There must be no non-phi instructions between the start of a basic block and
4928 the PHI instructions: i.e. PHI instructions must be first in a basic
4929 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4930
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4931<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4932 occur on the edge from the corresponding predecessor block to the current
4933 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4934 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]4935
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4936<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4937<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4938 specified by the pair corresponding to the predecessor basic block that
4939 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4940
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4941<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4942<pre>
4943Loop: ; Infinite loop that counts from 0 on up...
4944 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4945 %nextindvar = add i32 %indvar, 1
4946 br label %Loop
4947</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4948
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4949</div>
4950
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4951<!-- _______________________________________________________________________ -->
4952<div class="doc_subsubsection">
4953 <a name="i_select">'<tt>select</tt>' Instruction</a>
4954</div>
4955
4956<div class="doc_text">
4957
4958<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4959<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4960 &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>
4961
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4962 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4963</pre>
4964
4965<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4966<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4967 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4968
4969
4970<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4971<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4972 values indicating the condition, and two values of the
4973 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4974 vectors and the condition is a scalar, then entire vectors are selected, not
4975 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4976
4977<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4978<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4979 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4980
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4981<p>If the condition is a vector of i1, then the value arguments must be vectors
4982 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4983
4984<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4985<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4986 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4987</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4988
4989<p>Note that the code generator does not yet support conditions
4990 with vector type.</p>
4991
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4992</div>
4993
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]4994<!-- _______________________________________________________________________ -->
4995<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4996 <a name="i_call">'<tt>call</tt>' Instruction</a>
4997</div>
4998
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4999<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5000
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5001<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5002<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5003 &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]5004</pre>
5005
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5006<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5007<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5008
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5009<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5010<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5011
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5012<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5013 <li>The optional "tail" marker indicates whether the callee function accesses
5014 any allocas or varargs in the caller. If the "tail" marker is present,
5015 the function call is eligible for tail call optimization. Note that calls
5016 may be marked "tail" even if they do not occur before
5017 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5018
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5019 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5020 convention</a> the call should use. If none is specified, the call
5021 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5022
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5023 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5024 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5025 '<tt>inreg</tt>' attributes are valid here.</li>
5026
5027 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5028 type of the return value. Functions that return no value are marked
5029 <tt><a href="#t_void">void</a></tt>.</li>
5030
5031 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5032 being invoked. The argument types must match the types implied by this
5033 signature. This type can be omitted if the function is not varargs and if
5034 the function type does not return a pointer to a function.</li>
5035
5036 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5037 be invoked. In most cases, this is a direct function invocation, but
5038 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5039 to function value.</li>
5040
5041 <li>'<tt>function args</tt>': argument list whose types match the function
5042 signature argument types. All arguments must be of
5043 <a href="#t_firstclass">first class</a> type. If the function signature
5044 indicates the function accepts a variable number of arguments, the extra
5045 arguments can be specified.</li>
5046
5047 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5048 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5049 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5050</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5051
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5052<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5053<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5054 a specified function, with its incoming arguments bound to the specified
5055 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5056 function, control flow continues with the instruction after the function
5057 call, and the return value of the function is bound to the result
5058 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5059
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5060<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5061<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5062 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5063 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5064 %X = tail call i32 @foo() <i>; yields i32</i>
5065 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5066 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5067
5068 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5069 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5070 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5071 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5072 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5073 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5074</pre>
5075
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5076<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5077standard C99 library as being the C99 library functions, and may perform
5078optimizations or generate code for them under that assumption. This is
5079something we'd like to change in the future to provide better support for
5080freestanding environments and non-C-based langauges.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5081
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5082</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5083
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5084<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5085<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5086 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5087</div>
5088
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5089<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5090
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5091<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5092<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5093 &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]5094</pre>
5095
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5096<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5097<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5098 the "variable argument" area of a function call. It is used to implement the
5099 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5100
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5101<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5102<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5103 argument. It returns a value of the specified argument type and increments
5104 the <tt>va_list</tt> to point to the next argument. The actual type
5105 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5106
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5107<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5108<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5109 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5110 to the next argument. For more information, see the variable argument
5111 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5112
5113<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]5114 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5115 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5116
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5117<p><tt>va_arg</tt> is an LLVM instruction instead of
5118 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5119 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5120
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5121<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5122<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5123
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5124<p>Note that the code generator does not yet fully support va_arg on many
5125 targets. Also, it does not currently support va_arg with aggregate types on
5126 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5127
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5128</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5129
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5130<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5131<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5132<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5133
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5134<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5135
5136<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5137 well known names and semantics and are required to follow certain
5138 restrictions. Overall, these intrinsics represent an extension mechanism for
5139 the LLVM language that does not require changing all of the transformations
5140 in LLVM when adding to the language (or the bitcode reader/writer, the
5141 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5142
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5143<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5144 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5145 begin with this prefix. Intrinsic functions must always be external
5146 functions: you cannot define the body of intrinsic functions. Intrinsic
5147 functions may only be used in call or invoke instructions: it is illegal to
5148 take the address of an intrinsic function. Additionally, because intrinsic
5149 functions are part of the LLVM language, it is required if any are added that
5150 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5151
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5152<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5153 family of functions that perform the same operation but on different data
5154 types. Because LLVM can represent over 8 million different integer types,
5155 overloading is used commonly to allow an intrinsic function to operate on any
5156 integer type. One or more of the argument types or the result type can be
5157 overloaded to accept any integer type. Argument types may also be defined as
5158 exactly matching a previous argument's type or the result type. This allows
5159 an intrinsic function which accepts multiple arguments, but needs all of them
5160 to be of the same type, to only be overloaded with respect to a single
5161 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5162
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5163<p>Overloaded intrinsics will have the names of its overloaded argument types
5164 encoded into its function name, each preceded by a period. Only those types
5165 which are overloaded result in a name suffix. Arguments whose type is matched
5166 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5167 can take an integer of any width and returns an integer of exactly the same
5168 integer width. This leads to a family of functions such as
5169 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5170 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5171 suffix is required. Because the argument's type is matched against the return
5172 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5173
5174<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5175 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5176
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5177</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5178
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5179<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5180<div class="doc_subsection">
5181 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5182</div>
5183
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5184<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5185
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5186<p>Variable argument support is defined in LLVM with
5187 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5188 intrinsic functions. These functions are related to the similarly named
5189 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5190
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5191<p>All of these functions operate on arguments that use a target-specific value
5192 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5193 not define what this type is, so all transformations should be prepared to
5194 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5195
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5196<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]5197 instruction and the variable argument handling intrinsic functions are
5198 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5199
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5200<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5201<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5202define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5203 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5204 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5205 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5206 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5207
5208 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5209 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5210
5211 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5212 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5213 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5214 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5215 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5216
5217 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5218 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5219 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5220}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5221
5222declare void @llvm.va_start(i8*)
5223declare void @llvm.va_copy(i8*, i8*)
5224declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5225</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5226</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5227
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5228</div>
5229
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5230<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5231<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5232 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5233</div>
5234
5235
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5236<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5237
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5238<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5239<pre>
5240 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5241</pre>
5242
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5243<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5244<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5245 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]5246
5247<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5248<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]5249
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5250<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5251<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]5252 macro available in C. In a target-dependent way, it initializes
5253 the <tt>va_list</tt> element to which the argument points, so that the next
5254 call to <tt>va_arg</tt> will produce the first variable argument passed to
5255 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5256 need to know the last argument of the function as the compiler can figure
5257 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5258
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5259</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5260
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5261<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5262<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5263 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5264</div>
5265
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5266<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5267
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5268<h5>Syntax:</h5>
5269<pre>
5270 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5271</pre>
5272
5273<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5274<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5275 which has been initialized previously
5276 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5277 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5278
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5279<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5280<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]5281
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5282<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5283<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]5284 macro available in C. In a target-dependent way, it destroys
5285 the <tt>va_list</tt> element to which the argument points. Calls
5286 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5287 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5288 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5289
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5290</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5291
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5292<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5293<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5294 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5295</div>
5296
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5297<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5298
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5299<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5300<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5301 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5302</pre>
5303
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5304<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5305<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5306 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5307
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5308<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5309<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]5310 The second argument is a pointer to a <tt>va_list</tt> element to copy
5311 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5312
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5313<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5314<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]5315 macro available in C. In a target-dependent way, it copies the
5316 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5317 element. This intrinsic is necessary because
5318 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5319 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5320
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5321</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5322
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5323<!-- ======================================================================= -->
5324<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5325 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5326</div>
5327
5328<div class="doc_text">
5329
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5330<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5331Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5332intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5333roots on the stack</a>, as well as garbage collector implementations that
5334require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5335barriers. Front-ends for type-safe garbage collected languages should generate
5336these intrinsics to make use of the LLVM garbage collectors. For more details,
5337see <a href="GarbageCollection.html">Accurate Garbage Collection with
5338LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5339
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5340<p>The garbage collection intrinsics only operate on objects in the generic
5341 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5342
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5343</div>
5344
5345<!-- _______________________________________________________________________ -->
5346<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5347 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5348</div>
5349
5350<div class="doc_text">
5351
5352<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5353<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5354 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5355</pre>
5356
5357<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5358<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]5359 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5360
5361<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5362<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5363 root pointer. The second pointer (which must be either a constant or a
5364 global value address) contains the meta-data to be associated with the
5365 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5366
5367<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5368<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]5369 location. At compile-time, the code generator generates information to allow
5370 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5371 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5372 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5373
5374</div>
5375
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5376<!-- _______________________________________________________________________ -->
5377<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5378 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5379</div>
5380
5381<div class="doc_text">
5382
5383<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5384<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5385 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5386</pre>
5387
5388<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5389<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5390 locations, allowing garbage collector implementations that require read
5391 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5392
5393<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5394<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]5395 allocated from the garbage collector. The first object is a pointer to the
5396 start of the referenced object, if needed by the language runtime (otherwise
5397 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5398
5399<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5400<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5401 instruction, but may be replaced with substantially more complex code by the
5402 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5403 may only be used in a function which <a href="#gc">specifies a GC
5404 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5405
5406</div>
5407
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5408<!-- _______________________________________________________________________ -->
5409<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5410 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5411</div>
5412
5413<div class="doc_text">
5414
5415<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5416<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5417 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5418</pre>
5419
5420<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5421<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5422 locations, allowing garbage collector implementations that require write
5423 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5424
5425<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5426<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]5427 object to store it to, and the third is the address of the field of Obj to
5428 store to. If the runtime does not require a pointer to the object, Obj may
5429 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5430
5431<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5432<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5433 instruction, but may be replaced with substantially more complex code by the
5434 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5435 may only be used in a function which <a href="#gc">specifies a GC
5436 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5437
5438</div>
5439
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5440<!-- ======================================================================= -->
5441<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5442 <a name="int_codegen">Code Generator Intrinsics</a>
5443</div>
5444
5445<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5446
5447<p>These intrinsics are provided by LLVM to expose special features that may
5448 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5449
5450</div>
5451
5452<!-- _______________________________________________________________________ -->
5453<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5454 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5455</div>
5456
5457<div class="doc_text">
5458
5459<h5>Syntax:</h5>
5460<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5461 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5462</pre>
5463
5464<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5465<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5466 target-specific value indicating the return address of the current function
5467 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5468
5469<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5470<p>The argument to this intrinsic indicates which function to return the address
5471 for. Zero indicates the calling function, one indicates its caller, etc.
5472 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5473
5474<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5475<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5476 indicating the return address of the specified call frame, or zero if it
5477 cannot be identified. The value returned by this intrinsic is likely to be
5478 incorrect or 0 for arguments other than zero, so it should only be used for
5479 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5480
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5481<p>Note that calling this intrinsic does not prevent function inlining or other
5482 aggressive transformations, so the value returned may not be that of the
5483 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5484
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5485</div>
5486
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5487<!-- _______________________________________________________________________ -->
5488<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5489 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5490</div>
5491
5492<div class="doc_text">
5493
5494<h5>Syntax:</h5>
5495<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5496 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5497</pre>
5498
5499<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5500<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5501 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5502
5503<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5504<p>The argument to this intrinsic indicates which function to return the frame
5505 pointer for. Zero indicates the calling function, one indicates its caller,
5506 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5507
5508<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5509<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5510 indicating the frame address of the specified call frame, or zero if it
5511 cannot be identified. The value returned by this intrinsic is likely to be
5512 incorrect or 0 for arguments other than zero, so it should only be used for
5513 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5514
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5515<p>Note that calling this intrinsic does not prevent function inlining or other
5516 aggressive transformations, so the value returned may not be that of the
5517 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5518
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5519</div>
5520
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5521<!-- _______________________________________________________________________ -->
5522<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5523 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5524</div>
5525
5526<div class="doc_text">
5527
5528<h5>Syntax:</h5>
5529<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5530 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5531</pre>
5532
5533<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5534<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5535 of the function stack, for use
5536 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5537 useful for implementing language features like scoped automatic variable
5538 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5539
5540<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5541<p>This intrinsic returns a opaque pointer value that can be passed
5542 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5543 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5544 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5545 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5546 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5547 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5548
5549</div>
5550
5551<!-- _______________________________________________________________________ -->
5552<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5553 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5554</div>
5555
5556<div class="doc_text">
5557
5558<h5>Syntax:</h5>
5559<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5560 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5561</pre>
5562
5563<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5564<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5565 the function stack to the state it was in when the
5566 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5567 executed. This is useful for implementing language features like scoped
5568 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5569
5570<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5571<p>See the description
5572 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5573
5574</div>
5575
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5576<!-- _______________________________________________________________________ -->
5577<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5578 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5579</div>
5580
5581<div class="doc_text">
5582
5583<h5>Syntax:</h5>
5584<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5585 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]5586</pre>
5587
5588<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5589<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5590 insert a prefetch instruction if supported; otherwise, it is a noop.
5591 Prefetches have no effect on the behavior of the program but can change its
5592 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5593
5594<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5595<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5596 specifier determining if the fetch should be for a read (0) or write (1),
5597 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5598 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5599 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5600
5601<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5602<p>This intrinsic does not modify the behavior of the program. In particular,
5603 prefetches cannot trap and do not produce a value. On targets that support
5604 this intrinsic, the prefetch can provide hints to the processor cache for
5605 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5606
5607</div>
5608
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5609<!-- _______________________________________________________________________ -->
5610<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5611 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5612</div>
5613
5614<div class="doc_text">
5615
5616<h5>Syntax:</h5>
5617<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5618 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5619</pre>
5620
5621<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5622<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5623 Counter (PC) in a region of code to simulators and other tools. The method
5624 is target specific, but it is expected that the marker will use exported
5625 symbols to transmit the PC of the marker. The marker makes no guarantees
5626 that it will remain with any specific instruction after optimizations. It is
5627 possible that the presence of a marker will inhibit optimizations. The
5628 intended use is to be inserted after optimizations to allow correlations of
5629 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5630
5631<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5632<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5633
5634<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5635<p>This intrinsic does not modify the behavior of the program. Backends that do
5636 not support this intrinisic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5637
5638</div>
5639
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5640<!-- _______________________________________________________________________ -->
5641<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5642 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5643</div>
5644
5645<div class="doc_text">
5646
5647<h5>Syntax:</h5>
5648<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5649 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5650</pre>
5651
5652<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5653<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5654 counter register (or similar low latency, high accuracy clocks) on those
5655 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5656 should map to RPCC. As the backing counters overflow quickly (on the order
5657 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5658
5659<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5660<p>When directly supported, reading the cycle counter should not modify any
5661 memory. Implementations are allowed to either return a application specific
5662 value or a system wide value. On backends without support, this is lowered
5663 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5664
5665</div>
5666
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5667<!-- ======================================================================= -->
5668<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5669 <a name="int_libc">Standard C Library Intrinsics</a>
5670</div>
5671
5672<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5673
5674<p>LLVM provides intrinsics for a few important standard C library functions.
5675 These intrinsics allow source-language front-ends to pass information about
5676 the alignment of the pointer arguments to the code generator, providing
5677 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5678
5679</div>
5680
5681<!-- _______________________________________________________________________ -->
5682<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5683 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5684</div>
5685
5686<div class="doc_text">
5687
5688<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5689<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5690 integer bit width. Not all targets support all bit widths however.</p>
5691
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5692<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5693 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5694 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5695 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5696 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5697 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5698 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5699 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5700 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5701</pre>
5702
5703<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5704<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5705 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5706
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5707<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5708 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5709
5710<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5711<p>The first argument is a pointer to the destination, the second is a pointer
5712 to the source. The third argument is an integer argument specifying the
5713 number of bytes to copy, and the fourth argument is the alignment of the
5714 source and destination locations.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5715
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5716<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5717 then the caller guarantees that both the source and destination pointers are
5718 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5719
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5720<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5721<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5722 source location to the destination location, which are not allowed to
5723 overlap. It copies "len" bytes of memory over. If the argument is known to
5724 be aligned to some boundary, this can be specified as the fourth argument,
5725 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5726
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5727</div>
5728
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5729<!-- _______________________________________________________________________ -->
5730<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5731 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5732</div>
5733
5734<div class="doc_text">
5735
5736<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5737<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]5738 width. Not all targets support all bit widths however.</p>
5739
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5740<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5741 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5742 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5743 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5744 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5745 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5746 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5747 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5748 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5749</pre>
5750
5751<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5752<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5753 source location to the destination location. It is similar to the
5754 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5755 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5756
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5757<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5758 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5759
5760<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5761<p>The first argument is a pointer to the destination, the second is a pointer
5762 to the source. The third argument is an integer argument specifying the
5763 number of bytes to copy, and the fourth argument is the alignment of the
5764 source and destination locations.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5765
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5766<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5767 then the caller guarantees that the source and destination pointers are
5768 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5769
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5770<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5771<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5772 source location to the destination location, which may overlap. It copies
5773 "len" bytes of memory over. If the argument is known to be aligned to some
5774 boundary, this can be specified as the fourth argument, otherwise it should
5775 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5776
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5777</div>
5778
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5779<!-- _______________________________________________________________________ -->
5780<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5781 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5782</div>
5783
5784<div class="doc_text">
5785
5786<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5787<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]5788 width. Not all targets support all bit widths however.</p>
5789
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5790<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5791 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5792 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5793 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5794 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5795 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5796 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5797 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5798 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5799</pre>
5800
5801<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5802<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5803 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5804
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5805<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5806 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5807
5808<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5809<p>The first argument is a pointer to the destination to fill, the second is the
5810 byte value to fill it with, the third argument is an integer argument
5811 specifying the number of bytes to fill, and the fourth argument is the known
5812 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5813
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5814<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5815 then the caller guarantees that the destination pointer is aligned to that
5816 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5817
5818<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5819<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5820 at the destination location. If the argument is known to be aligned to some
5821 boundary, this can be specified as the fourth argument, otherwise it should
5822 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5823
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5824</div>
5825
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5826<!-- _______________________________________________________________________ -->
5827<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5828 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5829</div>
5830
5831<div class="doc_text">
5832
5833<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5834<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5835 floating point or vector of floating point type. Not all targets support all
5836 types however.</p>
5837
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5838<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5839 declare float @llvm.sqrt.f32(float %Val)
5840 declare double @llvm.sqrt.f64(double %Val)
5841 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5842 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5843 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5844</pre>
5845
5846<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5847<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5848 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5849 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5850 behavior for negative numbers other than -0.0 (which allows for better
5851 optimization, because there is no need to worry about errno being
5852 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]5853
5854<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5855<p>The argument and return value are floating point numbers of the same
5856 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5857
5858<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5859<p>This function returns the sqrt of the specified operand if it is a
5860 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5861
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5862</div>
5863
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5864<!-- _______________________________________________________________________ -->
5865<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5866 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5867</div>
5868
5869<div class="doc_text">
5870
5871<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5872<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5873 floating point or vector of floating point type. Not all targets support all
5874 types however.</p>
5875
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5876<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5877 declare float @llvm.powi.f32(float %Val, i32 %power)
5878 declare double @llvm.powi.f64(double %Val, i32 %power)
5879 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5880 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5881 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5882</pre>
5883
5884<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5885<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5886 specified (positive or negative) power. The order of evaluation of
5887 multiplications is not defined. When a vector of floating point type is
5888 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5889
5890<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5891<p>The second argument is an integer power, and the first is a value to raise to
5892 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5893
5894<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5895<p>This function returns the first value raised to the second power with an
5896 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5897
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5898</div>
5899
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5900<!-- _______________________________________________________________________ -->
5901<div class="doc_subsubsection">
5902 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5903</div>
5904
5905<div class="doc_text">
5906
5907<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5908<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5909 floating point or vector of floating point type. Not all targets support all
5910 types however.</p>
5911
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5912<pre>
5913 declare float @llvm.sin.f32(float %Val)
5914 declare double @llvm.sin.f64(double %Val)
5915 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5916 declare fp128 @llvm.sin.f128(fp128 %Val)
5917 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5918</pre>
5919
5920<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5921<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5922
5923<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5924<p>The argument and return value are floating point numbers of the same
5925 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5926
5927<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5928<p>This function returns the sine of the specified operand, returning the same
5929 values as the libm <tt>sin</tt> functions would, and handles error conditions
5930 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5931
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5932</div>
5933
5934<!-- _______________________________________________________________________ -->
5935<div class="doc_subsubsection">
5936 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5937</div>
5938
5939<div class="doc_text">
5940
5941<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5942<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5943 floating point or vector of floating point type. Not all targets support all
5944 types however.</p>
5945
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5946<pre>
5947 declare float @llvm.cos.f32(float %Val)
5948 declare double @llvm.cos.f64(double %Val)
5949 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5950 declare fp128 @llvm.cos.f128(fp128 %Val)
5951 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5952</pre>
5953
5954<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5955<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5956
5957<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5958<p>The argument and return value are floating point numbers of the same
5959 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5960
5961<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5962<p>This function returns the cosine of the specified operand, returning the same
5963 values as the libm <tt>cos</tt> functions would, and handles error conditions
5964 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5965
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5966</div>
5967
5968<!-- _______________________________________________________________________ -->
5969<div class="doc_subsubsection">
5970 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5971</div>
5972
5973<div class="doc_text">
5974
5975<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5976<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5977 floating point or vector of floating point type. Not all targets support all
5978 types however.</p>
5979
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5980<pre>
5981 declare float @llvm.pow.f32(float %Val, float %Power)
5982 declare double @llvm.pow.f64(double %Val, double %Power)
5983 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5984 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5985 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5986</pre>
5987
5988<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5989<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5990 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5991
5992<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5993<p>The second argument is a floating point power, and the first is a value to
5994 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5995
5996<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5997<p>This function returns the first value raised to the second power, returning
5998 the same values as the libm <tt>pow</tt> functions would, and handles error
5999 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6000
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6001</div>
6002
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6003<!-- ======================================================================= -->
6004<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6005 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6006</div>
6007
6008<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6009
6010<p>LLVM provides intrinsics for a few important bit manipulation operations.
6011 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6012
6013</div>
6014
6015<!-- _______________________________________________________________________ -->
6016<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6017 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6018</div>
6019
6020<div class="doc_text">
6021
6022<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6023<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6024 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6025
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6026<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6027 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6028 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6029 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6030</pre>
6031
6032<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6033<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6034 values with an even number of bytes (positive multiple of 16 bits). These
6035 are useful for performing operations on data that is not in the target's
6036 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6037
6038<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6039<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6040 and low byte of the input i16 swapped. Similarly,
6041 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6042 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6043 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6044 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6045 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6046 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6047
6048</div>
6049
6050<!-- _______________________________________________________________________ -->
6051<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6052 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6053</div>
6054
6055<div class="doc_text">
6056
6057<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6058<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]6059 width. Not all targets support all bit widths however.</p>
6060
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6061<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6062 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6063 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6064 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6065 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6066 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6067</pre>
6068
6069<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6070<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6071 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6072
6073<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6074<p>The only argument is the value to be counted. The argument may be of any
6075 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6076
6077<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6078<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]6079
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6080</div>
6081
6082<!-- _______________________________________________________________________ -->
6083<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6084 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6085</div>
6086
6087<div class="doc_text">
6088
6089<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6090<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6091 integer bit width. Not all targets support all bit widths however.</p>
6092
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6093<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6094 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6095 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6096 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6097 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6098 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6099</pre>
6100
6101<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6102<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6103 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6104
6105<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6106<p>The only argument is the value to be counted. The argument may be of any
6107 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6108
6109<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6110<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6111 zeros in a variable. If the src == 0 then the result is the size in bits of
6112 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6113
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6114</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6115
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6116<!-- _______________________________________________________________________ -->
6117<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6118 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6119</div>
6120
6121<div class="doc_text">
6122
6123<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6124<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6125 integer bit width. Not all targets support all bit widths however.</p>
6126
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6127<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6128 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6129 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6130 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6131 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6132 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6133</pre>
6134
6135<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6136<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6137 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6138
6139<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6140<p>The only argument is the value to be counted. The argument may be of any
6141 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6142
6143<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6144<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6145 zeros in a variable. If the src == 0 then the result is the size in bits of
6146 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6147
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6148</div>
6149
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6150<!-- ======================================================================= -->
6151<div class="doc_subsection">
6152 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6153</div>
6154
6155<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6156
6157<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6158
6159</div>
6160
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6161<!-- _______________________________________________________________________ -->
6162<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6163 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6164</div>
6165
6166<div class="doc_text">
6167
6168<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6169<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]6170 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6171
6172<pre>
6173 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6174 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6175 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6176</pre>
6177
6178<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6179<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6180 a signed addition of the two arguments, and indicate whether an overflow
6181 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6182
6183<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6184<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]6185 be of integer types of any bit width, but they must have the same bit
6186 width. The second element of the result structure must be of
6187 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6188 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6189
6190<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6191<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6192 a signed addition of the two variables. They return a structure &mdash; the
6193 first element of which is the signed summation, and the second element of
6194 which is a bit specifying if the signed summation resulted in an
6195 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6196
6197<h5>Examples:</h5>
6198<pre>
6199 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6200 %sum = extractvalue {i32, i1} %res, 0
6201 %obit = extractvalue {i32, i1} %res, 1
6202 br i1 %obit, label %overflow, label %normal
6203</pre>
6204
6205</div>
6206
6207<!-- _______________________________________________________________________ -->
6208<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6209 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6210</div>
6211
6212<div class="doc_text">
6213
6214<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6215<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]6216 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6217
6218<pre>
6219 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6220 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6221 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6222</pre>
6223
6224<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6225<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6226 an unsigned addition of the two arguments, and indicate whether a carry
6227 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6228
6229<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6230<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]6231 be of integer types of any bit width, but they must have the same bit
6232 width. The second element of the result structure must be of
6233 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6234 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6235
6236<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6237<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6238 an unsigned addition of the two arguments. They return a structure &mdash;
6239 the first element of which is the sum, and the second element of which is a
6240 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6241
6242<h5>Examples:</h5>
6243<pre>
6244 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6245 %sum = extractvalue {i32, i1} %res, 0
6246 %obit = extractvalue {i32, i1} %res, 1
6247 br i1 %obit, label %carry, label %normal
6248</pre>
6249
6250</div>
6251
6252<!-- _______________________________________________________________________ -->
6253<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6254 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6255</div>
6256
6257<div class="doc_text">
6258
6259<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6260<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]6261 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6262
6263<pre>
6264 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6265 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6266 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6267</pre>
6268
6269<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6270<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6271 a signed subtraction of the two arguments, and indicate whether an overflow
6272 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6273
6274<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6275<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]6276 be of integer types of any bit width, but they must have the same bit
6277 width. The second element of the result structure must be of
6278 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6279 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6280
6281<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6282<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6283 a signed subtraction of the two arguments. They return a structure &mdash;
6284 the first element of which is the subtraction, and the second element of
6285 which is a bit specifying if the signed subtraction resulted in an
6286 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6287
6288<h5>Examples:</h5>
6289<pre>
6290 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6291 %sum = extractvalue {i32, i1} %res, 0
6292 %obit = extractvalue {i32, i1} %res, 1
6293 br i1 %obit, label %overflow, label %normal
6294</pre>
6295
6296</div>
6297
6298<!-- _______________________________________________________________________ -->
6299<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6300 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6301</div>
6302
6303<div class="doc_text">
6304
6305<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6306<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]6307 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6308
6309<pre>
6310 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6311 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6312 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6313</pre>
6314
6315<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6316<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6317 an unsigned subtraction of the two arguments, and indicate whether an
6318 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6319
6320<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6321<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]6322 be of integer types of any bit width, but they must have the same bit
6323 width. The second element of the result structure must be of
6324 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6325 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6326
6327<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6328<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6329 an unsigned subtraction of the two arguments. They return a structure &mdash;
6330 the first element of which is the subtraction, and the second element of
6331 which is a bit specifying if the unsigned subtraction resulted in an
6332 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6333
6334<h5>Examples:</h5>
6335<pre>
6336 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6337 %sum = extractvalue {i32, i1} %res, 0
6338 %obit = extractvalue {i32, i1} %res, 1
6339 br i1 %obit, label %overflow, label %normal
6340</pre>
6341
6342</div>
6343
6344<!-- _______________________________________________________________________ -->
6345<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6346 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6347</div>
6348
6349<div class="doc_text">
6350
6351<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6352<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]6353 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6354
6355<pre>
6356 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6357 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6358 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6359</pre>
6360
6361<h5>Overview:</h5>
6362
6363<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6364 a signed multiplication of the two arguments, and indicate whether an
6365 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6366
6367<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6368<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]6369 be of integer types of any bit width, but they must have the same bit
6370 width. The second element of the result structure must be of
6371 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6372 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6373
6374<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6375<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6376 a signed multiplication of the two arguments. They return a structure &mdash;
6377 the first element of which is the multiplication, and the second element of
6378 which is a bit specifying if the signed multiplication resulted in an
6379 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6380
6381<h5>Examples:</h5>
6382<pre>
6383 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6384 %sum = extractvalue {i32, i1} %res, 0
6385 %obit = extractvalue {i32, i1} %res, 1
6386 br i1 %obit, label %overflow, label %normal
6387</pre>
6388
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6389</div>
6390
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6391<!-- _______________________________________________________________________ -->
6392<div class="doc_subsubsection">
6393 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6394</div>
6395
6396<div class="doc_text">
6397
6398<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6399<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]6400 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6401
6402<pre>
6403 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6404 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6405 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6406</pre>
6407
6408<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6409<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6410 a unsigned multiplication of the two arguments, and indicate whether an
6411 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6412
6413<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6414<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]6415 be of integer types of any bit width, but they must have the same bit
6416 width. The second element of the result structure must be of
6417 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6418 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6419
6420<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6421<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6422 an unsigned multiplication of the two arguments. They return a structure
6423 &mdash; the first element of which is the multiplication, and the second
6424 element of which is a bit specifying if the unsigned multiplication resulted
6425 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6426
6427<h5>Examples:</h5>
6428<pre>
6429 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6430 %sum = extractvalue {i32, i1} %res, 0
6431 %obit = extractvalue {i32, i1} %res, 1
6432 br i1 %obit, label %overflow, label %normal
6433</pre>
6434
6435</div>
6436
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6437<!-- ======================================================================= -->
6438<div class="doc_subsection">
6439 <a name="int_debugger">Debugger Intrinsics</a>
6440</div>
6441
6442<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6443
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6444<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6445 prefix), are described in
6446 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6447 Level Debugging</a> document.</p>
6448
6449</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6450
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6451<!-- ======================================================================= -->
6452<div class="doc_subsection">
6453 <a name="int_eh">Exception Handling Intrinsics</a>
6454</div>
6455
6456<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6457
6458<p>The LLVM exception handling intrinsics (which all start with
6459 <tt>llvm.eh.</tt> prefix), are described in
6460 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6461 Handling</a> document.</p>
6462
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6463</div>
6464
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6465<!-- ======================================================================= -->
6466<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6467 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6468</div>
6469
6470<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6471
6472<p>This intrinsic makes it possible to excise one parameter, marked with
6473 the <tt>nest</tt> attribute, from a function. The result is a callable
6474 function pointer lacking the nest parameter - the caller does not need to
6475 provide a value for it. Instead, the value to use is stored in advance in a
6476 "trampoline", a block of memory usually allocated on the stack, which also
6477 contains code to splice the nest value into the argument list. This is used
6478 to implement the GCC nested function address extension.</p>
6479
6480<p>For example, if the function is
6481 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6482 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6483 follows:</p>
6484
6485<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6486<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6487 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6488 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6489 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6490 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6491</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6492</div>
6493
6494<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6495 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6496
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6497</div>
6498
6499<!-- _______________________________________________________________________ -->
6500<div class="doc_subsubsection">
6501 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6502</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6503
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6504<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6505
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6506<h5>Syntax:</h5>
6507<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6508 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]6509</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6510
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6511<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6512<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6513 function pointer suitable for executing it.</p>
6514
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6515<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6516<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6517 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6518 sufficiently aligned block of memory; this memory is written to by the
6519 intrinsic. Note that the size and the alignment are target-specific - LLVM
6520 currently provides no portable way of determining them, so a front-end that
6521 generates this intrinsic needs to have some target-specific knowledge.
6522 The <tt>func</tt> argument must hold a function bitcast to
6523 an <tt>i8*</tt>.</p>
6524
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6525<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6526<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6527 dependent code, turning it into a function. A pointer to this function is
6528 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6529 function pointer type</a> before being called. The new function's signature
6530 is the same as that of <tt>func</tt> with any arguments marked with
6531 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6532 is allowed, and it must be of pointer type. Calling the new function is
6533 equivalent to calling <tt>func</tt> with the same argument list, but
6534 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6535 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6536 by <tt>tramp</tt> is modified, then the effect of any later call to the
6537 returned function pointer is undefined.</p>
6538
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6539</div>
6540
6541<!-- ======================================================================= -->
6542<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6543 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6544</div>
6545
6546<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6547
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6548<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6549 hardware constructs for atomic operations and memory synchronization. This
6550 provides an interface to the hardware, not an interface to the programmer. It
6551 is aimed at a low enough level to allow any programming models or APIs
6552 (Application Programming Interfaces) which need atomic behaviors to map
6553 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6554 hardware provides a "universal IR" for source languages, it also provides a
6555 starting point for developing a "universal" atomic operation and
6556 synchronization IR.</p>
6557
6558<p>These do <em>not</em> form an API such as high-level threading libraries,
6559 software transaction memory systems, atomic primitives, and intrinsic
6560 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6561 application libraries. The hardware interface provided by LLVM should allow
6562 a clean implementation of all of these APIs and parallel programming models.
6563 No one model or paradigm should be selected above others unless the hardware
6564 itself ubiquitously does so.</p>
6565
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6566</div>
6567
6568<!-- _______________________________________________________________________ -->
6569<div class="doc_subsubsection">
6570 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6571</div>
6572<div class="doc_text">
6573<h5>Syntax:</h5>
6574<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6575 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]6576</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6577
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6578<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6579<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6580 specific pairs of memory access types.</p>
6581
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6582<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6583<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6584 The first four arguments enables a specific barrier as listed below. The
6585 fith argument specifies that the barrier applies to io or device or uncached
6586 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6587
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6588<ul>
6589 <li><tt>ll</tt>: load-load barrier</li>
6590 <li><tt>ls</tt>: load-store barrier</li>
6591 <li><tt>sl</tt>: store-load barrier</li>
6592 <li><tt>ss</tt>: store-store barrier</li>
6593 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6594</ul>
6595
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6596<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6597<p>This intrinsic causes the system to enforce some ordering constraints upon
6598 the loads and stores of the program. This barrier does not
6599 indicate <em>when</em> any events will occur, it only enforces
6600 an <em>order</em> in which they occur. For any of the specified pairs of load
6601 and store operations (f.ex. load-load, or store-load), all of the first
6602 operations preceding the barrier will complete before any of the second
6603 operations succeeding the barrier begin. Specifically the semantics for each
6604 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6605
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6606<ul>
6607 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6608 after the barrier begins.</li>
6609 <li><tt>ls</tt>: All loads before the barrier must complete before any
6610 store after the barrier begins.</li>
6611 <li><tt>ss</tt>: All stores before the barrier must complete before any
6612 store after the barrier begins.</li>
6613 <li><tt>sl</tt>: All stores before the barrier must complete before any
6614 load after the barrier begins.</li>
6615</ul>
6616
6617<p>These semantics are applied with a logical "and" behavior when more than one
6618 is enabled in a single memory barrier intrinsic.</p>
6619
6620<p>Backends may implement stronger barriers than those requested when they do
6621 not support as fine grained a barrier as requested. Some architectures do
6622 not need all types of barriers and on such architectures, these become
6623 noops.</p>
6624
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6625<h5>Example:</h5>
6626<pre>
6627%ptr = malloc i32
6628 store i32 4, %ptr
6629
6630%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6631 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6632 <i>; guarantee the above finishes</i>
6633 store i32 8, %ptr <i>; before this begins</i>
6634</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6635
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6636</div>
6637
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6638<!-- _______________________________________________________________________ -->
6639<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6640 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6641</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6642
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6643<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6644
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6645<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6646<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6647 any integer bit width and for different address spaces. Not all targets
6648 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6649
6650<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6651 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6652 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6653 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6654 declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6655</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6656
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6657<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6658<p>This loads a value in memory and compares it to a given value. If they are
6659 equal, it stores a new value into the memory.</p>
6660
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6661<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6662<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6663 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6664 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6665 this integer type. While any bit width integer may be used, targets may only
6666 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6667
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6668<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6669<p>This entire intrinsic must be executed atomically. It first loads the value
6670 in memory pointed to by <tt>ptr</tt> and compares it with the
6671 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6672 memory. The loaded value is yielded in all cases. This provides the
6673 equivalent of an atomic compare-and-swap operation within the SSA
6674 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6675
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6676<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6677<pre>
6678%ptr = malloc i32
6679 store i32 4, %ptr
6680
6681%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6682%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6683 <i>; yields {i32}:result1 = 4</i>
6684%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6685%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6686
6687%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6688%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6689 <i>; yields {i32}:result2 = 8</i>
6690%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6691
6692%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6693</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6694
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6695</div>
6696
6697<!-- _______________________________________________________________________ -->
6698<div class="doc_subsubsection">
6699 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6700</div>
6701<div class="doc_text">
6702<h5>Syntax:</h5>
6703
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6704<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6705 integer bit width. Not all targets support all bit widths however.</p>
6706
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6707<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6708 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6709 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6710 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6711 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]6712</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6713
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6714<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6715<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6716 the value from memory. It then stores the value in <tt>val</tt> in the memory
6717 at <tt>ptr</tt>.</p>
6718
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6719<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6720<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6721 the <tt>val</tt> argument and the result must be integers of the same bit
6722 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6723 integer type. The targets may only lower integer representations they
6724 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6725
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6726<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6727<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6728 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6729 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6730
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6731<h5>Examples:</h5>
6732<pre>
6733%ptr = malloc i32
6734 store i32 4, %ptr
6735
6736%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6737%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6738 <i>; yields {i32}:result1 = 4</i>
6739%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6740%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6741
6742%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6743%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6744 <i>; yields {i32}:result2 = 8</i>
6745
6746%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6747%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6748</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6749
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6750</div>
6751
6752<!-- _______________________________________________________________________ -->
6753<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6754 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6755
6756</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6757
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6758<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6759
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6760<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6761<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6762 any integer bit width. Not all targets support all bit widths however.</p>
6763
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6764<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6765 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6766 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6767 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6768 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]6769</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6770
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6771<h5>Overview:</h5>
6772<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6773 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6774
6775<h5>Arguments:</h5>
6776<p>The intrinsic takes two arguments, the first a pointer to an integer value
6777 and the second an integer value. The result is also an integer value. These
6778 integer types can have any bit width, but they must all have the same bit
6779 width. The targets may only lower integer representations they support.</p>
6780
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6781<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6782<p>This intrinsic does a series of operations atomically. It first loads the
6783 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6784 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]6785
6786<h5>Examples:</h5>
6787<pre>
6788%ptr = malloc i32
6789 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6790%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6791 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6792%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6793 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6794%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6795 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6796%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6797</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6798
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6799</div>
6800
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6801<!-- _______________________________________________________________________ -->
6802<div class="doc_subsubsection">
6803 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6804
6805</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6806
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6807<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6808
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6809<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6810<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6811 any integer bit width and for different address spaces. Not all targets
6812 support all bit widths however.</p>
6813
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6814<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6815 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6816 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6817 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6818 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]6819</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6820
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6821<h5>Overview:</h5>
6822<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6823 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6824
6825<h5>Arguments:</h5>
6826<p>The intrinsic takes two arguments, the first a pointer to an integer value
6827 and the second an integer value. The result is also an integer value. These
6828 integer types can have any bit width, but they must all have the same bit
6829 width. The targets may only lower integer representations they support.</p>
6830
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6831<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6832<p>This intrinsic does a series of operations atomically. It first loads the
6833 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6834 result to <tt>ptr</tt>. It yields the original value stored
6835 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6836
6837<h5>Examples:</h5>
6838<pre>
6839%ptr = malloc i32
6840 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6841%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6842 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6843%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6844 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6845%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6846 <i>; yields {i32}:result3 = 2</i>
6847%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6848</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6849
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6850</div>
6851
6852<!-- _______________________________________________________________________ -->
6853<div class="doc_subsubsection">
6854 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6855 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6856 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6857 <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]6858</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6859
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6860<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6861
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6862<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6863<p>These are overloaded intrinsics. You can
6864 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6865 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6866 bit width and for different address spaces. Not all targets support all bit
6867 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6868
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6869<pre>
6870 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6871 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6872 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6873 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]6874</pre>
6875
6876<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6877 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6878 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6879 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6880 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]6881</pre>
6882
6883<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6884 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6885 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6886 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6887 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]6888</pre>
6889
6890<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6891 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6892 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6893 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6894 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]6895</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6896
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6897<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6898<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6899 the value stored in memory at <tt>ptr</tt>. It yields the original value
6900 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6901
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6902<h5>Arguments:</h5>
6903<p>These intrinsics take two arguments, the first a pointer to an integer value
6904 and the second an integer value. The result is also an integer value. These
6905 integer types can have any bit width, but they must all have the same bit
6906 width. The targets may only lower integer representations they support.</p>
6907
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6908<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6909<p>These intrinsics does a series of operations atomically. They first load the
6910 value stored at <tt>ptr</tt>. They then do the bitwise
6911 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6912 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6913
6914<h5>Examples:</h5>
6915<pre>
6916%ptr = malloc i32
6917 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6918%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6919 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6920%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6921 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6922%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6923 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6924%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6925 <i>; yields {i32}:result3 = FF</i>
6926%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6927</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6928
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6929</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6930
6931<!-- _______________________________________________________________________ -->
6932<div class="doc_subsubsection">
6933 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6934 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6935 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6936 <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]6937</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6938
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6939<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6940
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6941<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6942<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6943 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6944 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6945 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6946
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6947<pre>
6948 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6949 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6950 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6951 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]6952</pre>
6953
6954<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6955 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6956 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6957 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6958 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]6959</pre>
6960
6961<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6962 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6963 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6964 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6965 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]6966</pre>
6967
6968<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6969 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6970 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6971 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6972 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]6973</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6974
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6975<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6976<p>These intrinsics takes the signed or unsigned minimum or maximum of
6977 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6978 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6979
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6980<h5>Arguments:</h5>
6981<p>These intrinsics take two arguments, the first a pointer to an integer value
6982 and the second an integer value. The result is also an integer value. These
6983 integer types can have any bit width, but they must all have the same bit
6984 width. The targets may only lower integer representations they support.</p>
6985
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6986<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6987<p>These intrinsics does a series of operations atomically. They first load the
6988 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6989 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6990 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6991
6992<h5>Examples:</h5>
6993<pre>
6994%ptr = malloc 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
7046 never be used and has an undefined value. A load from the pointer that is
7047 preceded by this intrinsic can be replaced with
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
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7276 <a href="http://validator.w3.org/check/referer"><img
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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>