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gerrit-public.fairphone.software / toolchain / llvm-project / 722212d1a0672ae18a23db58c4cfb7e38073abfa / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencercb84e432004-08-26 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 Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 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 Lattner6af02f32004-12-09 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 Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 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>
34 <li><a href="#linkage_linkonce">'<tt>linkonce_odr</tt>' Linkage</a></li>
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 Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]46 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]47 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]48 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]49 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]50 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]51 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]52 </ol>
53 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]54 <li><a href="#typesystem">Type System</a>
55 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]56 <li><a href="#t_classifications">Type Classifications</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]58 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]59 <li><a href="#t_floating">Floating Point Types</a></li>
60 <li><a href="#t_void">Void Type</a></li>
61 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]62 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]63 </ol>
64 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]65 <li><a href="#t_derived">Derived Types</a>
66 <ol>
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]67 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]68 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]72 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]73 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]74 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]75 </ol>
76 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]77 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]78 </ol>
79 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]80 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]81 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]82 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]83 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 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 Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]87 <li><a href="#metadata">Embedded Metadata</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]88 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]89 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]90 <li><a href="#othervalues">Other Values</a>
91 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]93 </ol>
94 </li>
Chris Lattnerae76db52009-07-20 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 Lattner58f9bb22009-07-20 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 Lattnerae76db52009-07-20 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 Lattner2f7c9632001-06-06 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 Lattner48b383b02003-11-25 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 Brukman76307852003-11-08 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]114 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]115 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]116 </ol>
117 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]118 <li><a href="#binaryops">Binary Operations</a>
119 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]120 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]121 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 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 Spencer7eb55b32006-11-02 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]132 </ol>
133 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
135 <ol>
Reid Spencer2ab01932007-02-02 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 Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]139 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]141 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]142 </ol>
143 </li>
Chris Lattnerce83bff2006-04-08 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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]149 </ol>
150 </li>
Dan Gohmanb9d66602008-05-12 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 Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]157 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]158 <ol>
Chris Lattner48b383b02003-11-25 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 Bocchino820bc75b2006-02-17 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]165 </ol>
166 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]167 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 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 Spencer51b07252006-11-09 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 Spencerb7344ff2006-11-11 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 Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]180 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]181 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]182 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]183 <li><a href="#otherops">Other Operations</a>
184 <ol>
Reid Spencerc828a0e2006-11-18 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]187 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]188 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]189 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]190 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]191 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]192 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]193 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]194 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]195 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]196 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
198 <ol>
Reid Spencer96a5f022007-04-04 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]202 </ol>
203 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]204 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
205 <ol>
Reid Spencer96a5f022007-04-04 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 Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]209 </ol>
210 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]211 <li><a href="#int_codegen">Code Generator Intrinsics</a>
212 <ol>
Reid Spencer96a5f022007-04-04 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 Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]220 </ol>
221 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]222 <li><a href="#int_libc">Standard C Library Intrinsics</a>
223 <ol>
Reid Spencer96a5f022007-04-04 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 Gohmanb6324c12007-10-15 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 Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]232 </ol>
233 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]234 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]235 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]236 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 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 Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]240 </ol>
241 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]242 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
243 <ol>
Bill Wendlingfd2bd722009-02-08 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 Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]249 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]250 </ol>
251 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]252 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]253 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]254 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]255 <ol>
256 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]257 </ol>
258 </li>
Bill Wendlingf85850f2008-11-18 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>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]276 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]277 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]278 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]279 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]280 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]281 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]282 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]283 '<tt>llvm.trap</tt>' Intrinsic</a></li>
284 <li><a href="#int_stackprotector">
285 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]286 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]287 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]288 </ol>
289 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]290</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]291
292<div class="doc_author">
293 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
294 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]295</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]296
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]297<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]298<div class="doc_section"> <a name="abstract">Abstract </a></div>
299<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]300
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]301<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]302
303<p>This document is a reference manual for the LLVM assembly language. LLVM is
304 a Static Single Assignment (SSA) based representation that provides type
305 safety, low-level operations, flexibility, and the capability of representing
306 'all' high-level languages cleanly. It is the common code representation
307 used throughout all phases of the LLVM compilation strategy.</p>
308
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]309</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]310
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]311<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]312<div class="doc_section"> <a name="introduction">Introduction</a> </div>
313<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]314
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]315<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]316
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]317<p>The LLVM code representation is designed to be used in three different forms:
318 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
319 for fast loading by a Just-In-Time compiler), and as a human readable
320 assembly language representation. This allows LLVM to provide a powerful
321 intermediate representation for efficient compiler transformations and
322 analysis, while providing a natural means to debug and visualize the
323 transformations. The three different forms of LLVM are all equivalent. This
324 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]325
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]326<p>The LLVM representation aims to be light-weight and low-level while being
327 expressive, typed, and extensible at the same time. It aims to be a
328 "universal IR" of sorts, by being at a low enough level that high-level ideas
329 may be cleanly mapped to it (similar to how microprocessors are "universal
330 IR's", allowing many source languages to be mapped to them). By providing
331 type information, LLVM can be used as the target of optimizations: for
332 example, through pointer analysis, it can be proven that a C automatic
333 variable is never accessed outside of the current function... allowing it to
334 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]335
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]336</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]337
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]338<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]339<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]340
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]341<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]342
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]343<p>It is important to note that this document describes 'well formed' LLVM
344 assembly language. There is a difference between what the parser accepts and
345 what is considered 'well formed'. For example, the following instruction is
346 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]347
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]348<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]349<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]350%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]351</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]352</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]353
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]354<p>...because the definition of <tt>%x</tt> does not dominate all of its
355 uses. The LLVM infrastructure provides a verification pass that may be used
356 to verify that an LLVM module is well formed. This pass is automatically run
357 by the parser after parsing input assembly and by the optimizer before it
358 outputs bitcode. The violations pointed out by the verifier pass indicate
359 bugs in transformation passes or input to the parser.</p>
360
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]361</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]362
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]363<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]364
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]365<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]366<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]367<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]368
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]369<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]370
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]371<p>LLVM identifiers come in two basic types: global and local. Global
372 identifiers (functions, global variables) begin with the <tt>'@'</tt>
373 character. Local identifiers (register names, types) begin with
374 the <tt>'%'</tt> character. Additionally, there are three different formats
375 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]376
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]377<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]378 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]379 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
380 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
381 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
382 other characters in their names can be surrounded with quotes. Special
383 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
384 ASCII code for the character in hexadecimal. In this way, any character
385 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]386
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]387 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]388 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]389
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]390 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]391 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]392</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]393
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]394<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]395 don't need to worry about name clashes with reserved words, and the set of
396 reserved words may be expanded in the future without penalty. Additionally,
397 unnamed identifiers allow a compiler to quickly come up with a temporary
398 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]399
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]400<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]401 languages. There are keywords for different opcodes
402 ('<tt><a href="#i_add">add</a></tt>',
403 '<tt><a href="#i_bitcast">bitcast</a></tt>',
404 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
405 ('<tt><a href="#t_void">void</a></tt>',
406 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
407 reserved words cannot conflict with variable names, because none of them
408 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]409
410<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]411 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]412
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]413<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]414
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]415<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]416<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]417%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]418</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]419</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]420
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]421<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]422
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]423<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]424<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]425%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]426</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]427</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]428
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]429<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]430
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]431<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]432<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]433<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
434<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
435%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]436</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]437</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]438
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]439<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
440 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]441
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]442<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]443 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]444 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]445
446 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]447 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]449 <li>Unnamed temporaries are numbered sequentially</li>
450</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]451
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]452<p>...and it also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]453 demonstrating instructions, we will follow an instruction with a comment that
454 defines the type and name of value produced. Comments are shown in italic
455 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]456
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]457</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]458
459<!-- *********************************************************************** -->
460<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
461<!-- *********************************************************************** -->
462
463<!-- ======================================================================= -->
464<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
465</div>
466
467<div class="doc_text">
468
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]469<p>LLVM programs are composed of "Module"s, each of which is a translation unit
470 of the input programs. Each module consists of functions, global variables,
471 and symbol table entries. Modules may be combined together with the LLVM
472 linker, which merges function (and global variable) definitions, resolves
473 forward declarations, and merges symbol table entries. Here is an example of
474 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]475
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]476<div class="doc_code">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]477<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]478<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
479 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]480
481<i>; External declaration of the puts function</i>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]482<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]483
484<i>; Definition of main function</i>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]485define i32 @main() { <i>; i32()* </i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]486 <i>; Convert [13 x i8]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]487 %cast210 = <a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]488 href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]489
490 <i>; Call puts function to write out the string to stdout...</i>
491 <a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]492 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493 <a
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]494 href="#i_ret">ret</a> i32 0<br>}<br>
495</pre>
496</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]497
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]498<p>This example is made up of a <a href="#globalvars">global variable</a> named
499 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
500 a <a href="#functionstructure">function definition</a> for
501 "<tt>main</tt>".</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]502
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]503<p>In general, a module is made up of a list of global values, where both
504 functions and global variables are global values. Global values are
505 represented by a pointer to a memory location (in this case, a pointer to an
506 array of char, and a pointer to a function), and have one of the
507 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]508
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]509</div>
510
511<!-- ======================================================================= -->
512<div class="doc_subsection">
513 <a name="linkage">Linkage Types</a>
514</div>
515
516<div class="doc_text">
517
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]518<p>All Global Variables and Functions have one of the following types of
519 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]520
521<dl>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]522 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]523 <dd>Global values with private linkage are only directly accessible by objects
524 in the current module. In particular, linking code into a module with an
525 private global value may cause the private to be renamed as necessary to
526 avoid collisions. Because the symbol is private to the module, all
527 references can be updated. This doesn't show up in any symbol table in the
528 object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]529
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]530 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]531 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere7f064e2009-08-24 04:32:16 +0000[diff] [blame]532 removed by the linker after evaluation. Note that (unlike private
533 symbols) linker_private symbols are subject to coalescing by the linker:
534 weak symbols get merged and redefinitions are rejected. However, unlike
535 normal strong symbols, they are removed by the linker from the final
536 linked image (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]537
Dale Johannesen4188aad2008-05-23 23:13:41 +0000[diff] [blame]538 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]539 <dd>Similar to private, but the value shows as a local symbol
540 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
541 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]542
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]544 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]545 into the object file corresponding to the LLVM module. They exist to
546 allow inlining and other optimizations to take place given knowledge of
547 the definition of the global, which is known to be somewhere outside the
548 module. Globals with <tt>available_externally</tt> linkage are allowed to
549 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
550 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]551
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]552 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]553 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]554 the same name when linkage occurs. This is typically used to implement
555 inline functions, templates, or other code which must be generated in each
556 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
557 allowed to be discarded.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]558
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]559 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]560 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
561 <tt>linkonce</tt> linkage, except that unreferenced globals with
562 <tt>weak</tt> linkage may not be discarded. This is used for globals that
563 are declared "weak" in C source code.</dd>
564
565 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
566 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
567 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
568 global scope.
569 Symbols with "<tt>common</tt>" linkage are merged in the same way as
570 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]571 <tt>common</tt> symbols may not have an explicit section,
572 must have a zero initializer, and may not be marked '<a
573 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
574 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]575
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]576
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]578 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]579 pointer to array type. When two global variables with appending linkage
580 are linked together, the two global arrays are appended together. This is
581 the LLVM, typesafe, equivalent of having the system linker append together
582 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]583
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]585 <dd>The semantics of this linkage follow the ELF object file model: the symbol
586 is weak until linked, if not linked, the symbol becomes null instead of
587 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]588
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]591 <dd>Some languages allow differing globals to be merged, such as two functions
592 with different semantics. Other languages, such as <tt>C++</tt>, ensure
593 that only equivalent globals are ever merged (the "one definition rule" -
594 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
595 and <tt>weak_odr</tt> linkage types to indicate that the global will only
596 be merged with equivalent globals. These linkage types are otherwise the
597 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]598
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]599 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]600 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]601 visible, meaning that it participates in linkage and can be used to
602 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]603</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]604
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]605<p>The next two types of linkage are targeted for Microsoft Windows platform
606 only. They are designed to support importing (exporting) symbols from (to)
607 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]608
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]609<dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]611 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]612 or variable via a global pointer to a pointer that is set up by the DLL
613 exporting the symbol. On Microsoft Windows targets, the pointer name is
614 formed by combining <code>__imp_</code> and the function or variable
615 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]616
617 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]618 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]619 pointer to a pointer in a DLL, so that it can be referenced with the
620 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
621 name is formed by combining <code>__imp_</code> and the function or
622 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]623</dl>
624
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]625<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
626 another module defined a "<tt>.LC0</tt>" variable and was linked with this
627 one, one of the two would be renamed, preventing a collision. Since
628 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
629 declarations), they are accessible outside of the current module.</p>
630
631<p>It is illegal for a function <i>declaration</i> to have any linkage type
632 other than "externally visible", <tt>dllimport</tt>
633 or <tt>extern_weak</tt>.</p>
634
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]635<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]636 or <tt>weak_odr</tt> linkages.</p>
637
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]638</div>
639
640<!-- ======================================================================= -->
641<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]642 <a name="callingconv">Calling Conventions</a>
643</div>
644
645<div class="doc_text">
646
647<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]648 and <a href="#i_invoke">invokes</a> can all have an optional calling
649 convention specified for the call. The calling convention of any pair of
650 dynamic caller/callee must match, or the behavior of the program is
651 undefined. The following calling conventions are supported by LLVM, and more
652 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]653
654<dl>
655 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]656 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]657 specified) matches the target C calling conventions. This calling
658 convention supports varargs function calls and tolerates some mismatch in
659 the declared prototype and implemented declaration of the function (as
660 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]661
662 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]663 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]664 (e.g. by passing things in registers). This calling convention allows the
665 target to use whatever tricks it wants to produce fast code for the
666 target, without having to conform to an externally specified ABI
667 (Application Binary Interface). Implementations of this convention should
668 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
669 optimization</a> to be supported. This calling convention does not
670 support varargs and requires the prototype of all callees to exactly match
671 the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]672
673 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]674 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]675 as possible under the assumption that the call is not commonly executed.
676 As such, these calls often preserve all registers so that the call does
677 not break any live ranges in the caller side. This calling convention
678 does not support varargs and requires the prototype of all callees to
679 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]680
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]681 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]682 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]683 target-specific calling conventions to be used. Target specific calling
684 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]685</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]686
687<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]688 support Pascal conventions or any other well-known target-independent
689 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]690
691</div>
692
693<!-- ======================================================================= -->
694<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]695 <a name="visibility">Visibility Styles</a>
696</div>
697
698<div class="doc_text">
699
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]700<p>All Global Variables and Functions have one of the following visibility
701 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]702
703<dl>
704 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]705 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]706 that the declaration is visible to other modules and, in shared libraries,
707 means that the declared entity may be overridden. On Darwin, default
708 visibility means that the declaration is visible to other modules. Default
709 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]710
711 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]712 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]713 object if they are in the same shared object. Usually, hidden visibility
714 indicates that the symbol will not be placed into the dynamic symbol
715 table, so no other module (executable or shared library) can reference it
716 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]717
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]718 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]719 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]720 the dynamic symbol table, but that references within the defining module
721 will bind to the local symbol. That is, the symbol cannot be overridden by
722 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]723</dl>
724
725</div>
726
727<!-- ======================================================================= -->
728<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]729 <a name="namedtypes">Named Types</a>
730</div>
731
732<div class="doc_text">
733
734<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]735 it easier to read the IR and make the IR more condensed (particularly when
736 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]737
738<div class="doc_code">
739<pre>
740%mytype = type { %mytype*, i32 }
741</pre>
742</div>
743
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]744<p>You may give a name to any <a href="#typesystem">type</a> except
745 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
746 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]747
748<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]749 and that you can therefore specify multiple names for the same type. This
750 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
751 uses structural typing, the name is not part of the type. When printing out
752 LLVM IR, the printer will pick <em>one name</em> to render all types of a
753 particular shape. This means that if you have code where two different
754 source types end up having the same LLVM type, that the dumper will sometimes
755 print the "wrong" or unexpected type. This is an important design point and
756 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]757
758</div>
759
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]760<!-- ======================================================================= -->
761<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]762 <a name="globalvars">Global Variables</a>
763</div>
764
765<div class="doc_text">
766
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]767<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]768 instead of run-time. Global variables may optionally be initialized, may
769 have an explicit section to be placed in, and may have an optional explicit
770 alignment specified. A variable may be defined as "thread_local", which
771 means that it will not be shared by threads (each thread will have a
772 separated copy of the variable). A variable may be defined as a global
773 "constant," which indicates that the contents of the variable
774 will <b>never</b> be modified (enabling better optimization, allowing the
775 global data to be placed in the read-only section of an executable, etc).
776 Note that variables that need runtime initialization cannot be marked
777 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]778
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]779<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
780 constant, even if the final definition of the global is not. This capability
781 can be used to enable slightly better optimization of the program, but
782 requires the language definition to guarantee that optimizations based on the
783 'constantness' are valid for the translation units that do not include the
784 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]785
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]786<p>As SSA values, global variables define pointer values that are in scope
787 (i.e. they dominate) all basic blocks in the program. Global variables
788 always define a pointer to their "content" type because they describe a
789 region of memory, and all memory objects in LLVM are accessed through
790 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]791
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]792<p>A global variable may be declared to reside in a target-specific numbered
793 address space. For targets that support them, address spaces may affect how
794 optimizations are performed and/or what target instructions are used to
795 access the variable. The default address space is zero. The address space
796 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]797
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]798<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]799 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]800
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]801<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]802 the alignment is set to zero, the alignment of the global is set by the
803 target to whatever it feels convenient. If an explicit alignment is
804 specified, the global is forced to have at least that much alignment. All
805 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]806
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]807<p>For example, the following defines a global in a numbered address space with
808 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]809
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]810<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]811<pre>
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]812@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]813</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]814</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]815
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]816</div>
817
818
819<!-- ======================================================================= -->
820<div class="doc_subsection">
821 <a name="functionstructure">Functions</a>
822</div>
823
824<div class="doc_text">
825
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]826<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
827 optional <a href="#linkage">linkage type</a>, an optional
828 <a href="#visibility">visibility style</a>, an optional
829 <a href="#callingconv">calling convention</a>, a return type, an optional
830 <a href="#paramattrs">parameter attribute</a> for the return type, a function
831 name, a (possibly empty) argument list (each with optional
832 <a href="#paramattrs">parameter attributes</a>), optional
833 <a href="#fnattrs">function attributes</a>, an optional section, an optional
834 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
835 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]836
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]837<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
838 optional <a href="#linkage">linkage type</a>, an optional
839 <a href="#visibility">visibility style</a>, an optional
840 <a href="#callingconv">calling convention</a>, a return type, an optional
841 <a href="#paramattrs">parameter attribute</a> for the return type, a function
842 name, a possibly empty list of arguments, an optional alignment, and an
843 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]844
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]845<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]846 (Control Flow Graph) for the function. Each basic block may optionally start
847 with a label (giving the basic block a symbol table entry), contains a list
848 of instructions, and ends with a <a href="#terminators">terminator</a>
849 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]850
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]851<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]852 executed on entrance to the function, and it is not allowed to have
853 predecessor basic blocks (i.e. there can not be any branches to the entry
854 block of a function). Because the block can have no predecessors, it also
855 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]856
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]857<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]858 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]859
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]860<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]861 the alignment is set to zero, the alignment of the function is set by the
862 target to whatever it feels convenient. If an explicit alignment is
863 specified, the function is forced to have at least that much alignment. All
864 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]865
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]866<h5>Syntax:</h5>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]867<div class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]868<pre>
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]869define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]870 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
871 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
872 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
873 [<a href="#gc">gc</a>] { ... }
874</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]875</div>
876
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]877</div>
878
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]879<!-- ======================================================================= -->
880<div class="doc_subsection">
881 <a name="aliasstructure">Aliases</a>
882</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]883
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]884<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]885
886<p>Aliases act as "second name" for the aliasee value (which can be either
887 function, global variable, another alias or bitcast of global value). Aliases
888 may have an optional <a href="#linkage">linkage type</a>, and an
889 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]890
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]891<h5>Syntax:</h5>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]892<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]893<pre>
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]894@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]895</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]896</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]897
898</div>
899
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]900<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]901<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]902
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]903<div class="doc_text">
904
905<p>The return type and each parameter of a function type may have a set of
906 <i>parameter attributes</i> associated with them. Parameter attributes are
907 used to communicate additional information about the result or parameters of
908 a function. Parameter attributes are considered to be part of the function,
909 not of the function type, so functions with different parameter attributes
910 can have the same function type.</p>
911
912<p>Parameter attributes are simple keywords that follow the type specified. If
913 multiple parameter attributes are needed, they are space separated. For
914 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]915
916<div class="doc_code">
917<pre>
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]918declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]919declare i32 @atoi(i8 zeroext)
920declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]921</pre>
922</div>
923
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]924<p>Note that any attributes for the function result (<tt>nounwind</tt>,
925 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]926
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]927<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]928
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]929<dl>
930 <dt><tt>zeroext</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]931 <dd>This indicates to the code generator that the parameter or return value
932 should be zero-extended to a 32-bit value by the caller (for a parameter)
933 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]934
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]935 <dt><tt>signext</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]936 <dd>This indicates to the code generator that the parameter or return value
937 should be sign-extended to a 32-bit value by the caller (for a parameter)
938 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]939
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940 <dt><tt>inreg</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]941 <dd>This indicates that this parameter or return value should be treated in a
942 special target-dependent fashion during while emitting code for a function
943 call or return (usually, by putting it in a register as opposed to memory,
944 though some targets use it to distinguish between two different kinds of
945 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]946
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]947 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]948 <dd>This indicates that the pointer parameter should really be passed by value
949 to the function. The attribute implies that a hidden copy of the pointee
950 is made between the caller and the callee, so the callee is unable to
951 modify the value in the callee. This attribute is only valid on LLVM
952 pointer arguments. It is generally used to pass structs and arrays by
953 value, but is also valid on pointers to scalars. The copy is considered
954 to belong to the caller not the callee (for example,
955 <tt><a href="#readonly">readonly</a></tt> functions should not write to
956 <tt>byval</tt> parameters). This is not a valid attribute for return
957 values. The byval attribute also supports specifying an alignment with
958 the align attribute. This has a target-specific effect on the code
959 generator that usually indicates a desired alignment for the synthesized
960 stack slot.</dd>
961
962 <dt><tt>sret</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]963 <dd>This indicates that the pointer parameter specifies the address of a
964 structure that is the return value of the function in the source program.
965 This pointer must be guaranteed by the caller to be valid: loads and
966 stores to the structure may be assumed by the callee to not to trap. This
967 may only be applied to the first parameter. This is not a valid attribute
968 for return values. </dd>
969
970 <dt><tt>noalias</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]971 <dd>This indicates that the pointer does not alias any global or any other
972 parameter. The caller is responsible for ensuring that this is the
973 case. On a function return value, <tt>noalias</tt> additionally indicates
974 that the pointer does not alias any other pointers visible to the
975 caller. For further details, please see the discussion of the NoAlias
976 response in
977 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
978 analysis</a>.</dd>
979
980 <dt><tt>nocapture</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]981 <dd>This indicates that the callee does not make any copies of the pointer
982 that outlive the callee itself. This is not a valid attribute for return
983 values.</dd>
984
985 <dt><tt>nest</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]986 <dd>This indicates that the pointer parameter can be excised using the
987 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
988 attribute for return values.</dd>
989</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]990
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]991</div>
992
993<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]994<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]995 <a name="gc">Garbage Collector Names</a>
996</div>
997
998<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]999
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1000<p>Each function may specify a garbage collector name, which is simply a
1001 string:</p>
1002
1003<div class="doc_code">
1004<pre>
1005define void @f() gc "name" { ...
1006</pre>
1007</div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1008
1009<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1010 collector which will cause the compiler to alter its output in order to
1011 support the named garbage collection algorithm.</p>
1012
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1013</div>
1014
1015<!-- ======================================================================= -->
1016<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1017 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1018</div>
1019
1020<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1021
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1022<p>Function attributes are set to communicate additional information about a
1023 function. Function attributes are considered to be part of the function, not
1024 of the function type, so functions with different parameter attributes can
1025 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1026
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1027<p>Function attributes are simple keywords that follow the type specified. If
1028 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1029
1030<div class="doc_code">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1031<pre>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1032define void @f() noinline { ... }
1033define void @f() alwaysinline { ... }
1034define void @f() alwaysinline optsize { ... }
1035define void @f() optsize
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1036</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1037</div>
1038
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1039<dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1040 <dt><tt>alwaysinline</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This attribute indicates that the inliner should attempt to inline this
1042 function into callers whenever possible, ignoring any active inlining size
1043 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1044
Dale Johannesen2aaf5392009-08-26 01:08:21 +0000[diff] [blame]1045 <dt><tt>inlinehint</tt></dt>
1046 <dd>This attribute indicates that the source code contained a hint that inlining
1047 this function is desirable (such as the "inline" keyword in C/C++). It
1048 is just a hint; it imposes no requirements on the inliner.</dd>
1049
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1050 <dt><tt>noinline</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1051 <dd>This attribute indicates that the inliner should never inline this
1052 function in any situation. This attribute may not be used together with
1053 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1054
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1055 <dt><tt>optsize</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This attribute suggests that optimization passes and code generator passes
1057 make choices that keep the code size of this function low, and otherwise
1058 do optimizations specifically to reduce code size.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1059
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1060 <dt><tt>noreturn</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This function attribute indicates that the function never returns
1062 normally. This produces undefined behavior at runtime if the function
1063 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1064
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1065 <dt><tt>nounwind</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This function attribute indicates that the function never returns with an
1067 unwind or exceptional control flow. If the function does unwind, its
1068 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1069
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1070 <dt><tt>readnone</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This attribute indicates that the function computes its result (or decides
1072 to unwind an exception) based strictly on its arguments, without
1073 dereferencing any pointer arguments or otherwise accessing any mutable
1074 state (e.g. memory, control registers, etc) visible to caller functions.
1075 It does not write through any pointer arguments
1076 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1077 changes any state visible to callers. This means that it cannot unwind
1078 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1079 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1080
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1081 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1082 <dd>This attribute indicates that the function does not write through any
1083 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1084 arguments) or otherwise modify any state (e.g. memory, control registers,
1085 etc) visible to caller functions. It may dereference pointer arguments
1086 and read state that may be set in the caller. A readonly function always
1087 returns the same value (or unwinds an exception identically) when called
1088 with the same set of arguments and global state. It cannot unwind an
1089 exception by calling the <tt>C++</tt> exception throwing methods, but may
1090 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1091
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1092 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1093 <dd>This attribute indicates that the function should emit a stack smashing
1094 protector. It is in the form of a "canary"&mdash;a random value placed on
1095 the stack before the local variables that's checked upon return from the
1096 function to see if it has been overwritten. A heuristic is used to
1097 determine if a function needs stack protectors or not.<br>
1098<br>
1099 If a function that has an <tt>ssp</tt> attribute is inlined into a
1100 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1101 function will have an <tt>ssp</tt> attribute.</dd>
1102
1103 <dt><tt>sspreq</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1104 <dd>This attribute indicates that the function should <em>always</em> emit a
1105 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1106 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1107<br>
1108 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1109 function that doesn't have an <tt>sspreq</tt> attribute or which has
1110 an <tt>ssp</tt> attribute, then the resulting function will have
1111 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1112
1113 <dt><tt>noredzone</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1114 <dd>This attribute indicates that the code generator should not use a red
1115 zone, even if the target-specific ABI normally permits it.</dd>
1116
1117 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1118 <dd>This attributes disables implicit floating point instructions.</dd>
1119
1120 <dt><tt>naked</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1121 <dd>This attribute disables prologue / epilogue emission for the function.
1122 This can have very system-specific consequences.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1123</dl>
1124
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1125</div>
1126
1127<!-- ======================================================================= -->
1128<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1129 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1130</div>
1131
1132<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1133
1134<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1135 the GCC "file scope inline asm" blocks. These blocks are internally
1136 concatenated by LLVM and treated as a single unit, but may be separated in
1137 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1138
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1139<div class="doc_code">
1140<pre>
1141module asm "inline asm code goes here"
1142module asm "more can go here"
1143</pre>
1144</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1145
1146<p>The strings can contain any character by escaping non-printable characters.
1147 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1148 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1149
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1150<p>The inline asm code is simply printed to the machine code .s file when
1151 assembly code is generated.</p>
1152
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1153</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1154
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1155<!-- ======================================================================= -->
1156<div class="doc_subsection">
1157 <a name="datalayout">Data Layout</a>
1158</div>
1159
1160<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1161
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1162<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1163 data is to be laid out in memory. The syntax for the data layout is
1164 simply:</p>
1165
1166<div class="doc_code">
1167<pre>
1168target datalayout = "<i>layout specification</i>"
1169</pre>
1170</div>
1171
1172<p>The <i>layout specification</i> consists of a list of specifications
1173 separated by the minus sign character ('-'). Each specification starts with
1174 a letter and may include other information after the letter to define some
1175 aspect of the data layout. The specifications accepted are as follows:</p>
1176
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1177<dl>
1178 <dt><tt>E</tt></dt>
1179 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1180 bits with the most significance have the lowest address location.</dd>
1181
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1182 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1183 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1184 the bits with the least significance have the lowest address
1185 location.</dd>
1186
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1187 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1188 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1189 <i>preferred</i> alignments. All sizes are in bits. Specifying
1190 the <i>pref</i> alignment is optional. If omitted, the
1191 preceding <tt>:</tt> should be omitted too.</dd>
1192
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1193 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1194 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1195 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1196
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1197 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1198 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1199 <i>size</i>.</dd>
1200
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1201 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1202 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1203 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1204 (double).</dd>
1205
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1206 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1207 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1208 <i>size</i>.</dd>
1209
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1210 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1211 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1212 <i>size</i>.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1213</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1214
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1215<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1216 default set of specifications which are then (possibly) overriden by the
1217 specifications in the <tt>datalayout</tt> keyword. The default specifications
1218 are given in this list:</p>
1219
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1220<ul>
1221 <li><tt>E</tt> - big endian</li>
1222 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1223 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1224 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1225 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1226 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1227 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1228 alignment of 64-bits</li>
1229 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1230 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1231 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1232 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1233 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1234 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1235</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1236
1237<p>When LLVM is determining the alignment for a given type, it uses the
1238 following rules:</p>
1239
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1240<ol>
1241 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1242 specification is used.</li>
1243
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1244 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1245 smallest integer type that is larger than the bitwidth of the sought type
1246 is used. If none of the specifications are larger than the bitwidth then
1247 the the largest integer type is used. For example, given the default
1248 specifications above, the i7 type will use the alignment of i8 (next
1249 largest) while both i65 and i256 will use the alignment of i64 (largest
1250 specified).</li>
1251
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1252 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1253 largest vector type that is smaller than the sought vector type will be
1254 used as a fall back. This happens because &lt;128 x double&gt; can be
1255 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1256</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1257
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1258</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1259
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1260<!-- ======================================================================= -->
1261<div class="doc_subsection">
1262 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1263</div>
1264
1265<div class="doc_text">
1266
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1267<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1268with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1269is undefined. Pointer values are associated with address ranges
1270according to the following rules:</p>
1271
1272<ul>
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1273 <li>A pointer value formed from a
1274 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1275 is associated with the addresses associated with the first operand
1276 of the <tt>getelementptr</tt>.</li>
1277 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1278 range of the variable's storage.</li>
1279 <li>The result value of an allocation instruction is associated with
1280 the address range of the allocated storage.</li>
1281 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1282 no address.</li>
1283 <li>A pointer value formed by an
1284 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1285 address ranges of all pointer values that contribute (directly or
1286 indirectly) to the computation of the pointer's value.</li>
1287 <li>The result value of a
1288 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1289 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1290 <li>An integer constant other than zero or a pointer value returned
1291 from a function not defined within LLVM may be associated with address
1292 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1293 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1294 allocated by mechanisms provided by LLVM.</li>
1295 </ul>
1296
1297<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1298<tt><a href="#i_load">load</a></tt> merely indicates the size and
1299alignment of the memory from which to load, as well as the
1300interpretation of the value. The first operand of a
1301<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1302and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1303
1304<p>Consequently, type-based alias analysis, aka TBAA, aka
1305<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1306LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1307additional information which specialized optimization passes may use
1308to implement type-based alias analysis.</p>
1309
1310</div>
1311
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1312<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1313<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1314<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1315
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1316<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1317
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1318<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1319 intermediate representation. Being typed enables a number of optimizations
1320 to be performed on the intermediate representation directly, without having
1321 to do extra analyses on the side before the transformation. A strong type
1322 system makes it easier to read the generated code and enables novel analyses
1323 and transformations that are not feasible to perform on normal three address
1324 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1325
1326</div>
1327
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1328<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1329<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1330Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1331
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1332<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1333
1334<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1335
1336<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1337 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1338 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1339 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1340 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1341 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1342 </tr>
1343 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1344 <td><a href="#t_floating">floating point</a></td>
1345 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1346 </tr>
1347 <tr>
1348 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1349 <td><a href="#t_integer">integer</a>,
1350 <a href="#t_floating">floating point</a>,
1351 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1352 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1353 <a href="#t_struct">structure</a>,
1354 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1355 <a href="#t_label">label</a>,
1356 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1357 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1358 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1359 <tr>
1360 <td><a href="#t_primitive">primitive</a></td>
1361 <td><a href="#t_label">label</a>,
1362 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1363 <a href="#t_floating">floating point</a>,
1364 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1365 </tr>
1366 <tr>
1367 <td><a href="#t_derived">derived</a></td>
1368 <td><a href="#t_integer">integer</a>,
1369 <a href="#t_array">array</a>,
1370 <a href="#t_function">function</a>,
1371 <a href="#t_pointer">pointer</a>,
1372 <a href="#t_struct">structure</a>,
1373 <a href="#t_pstruct">packed structure</a>,
1374 <a href="#t_vector">vector</a>,
1375 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1376 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1377 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1378 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1379</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1380
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1381<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1382 important. Values of these types are the only ones which can be produced by
1383 instructions, passed as arguments, or used as operands to instructions.</p>
1384
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1385</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1386
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1387<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1388<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1389
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1390<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1391
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1392<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1393 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1394
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1395</div>
1396
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1397<!-- _______________________________________________________________________ -->
1398<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1399
1400<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1401
1402<table>
1403 <tbody>
1404 <tr><th>Type</th><th>Description</th></tr>
1405 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1406 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1407 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1408 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1409 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1410 </tbody>
1411</table>
1412
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1413</div>
1414
1415<!-- _______________________________________________________________________ -->
1416<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1417
1418<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1419
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1420<h5>Overview:</h5>
1421<p>The void type does not represent any value and has no size.</p>
1422
1423<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1424<pre>
1425 void
1426</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1427
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1428</div>
1429
1430<!-- _______________________________________________________________________ -->
1431<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1432
1433<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1434
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1435<h5>Overview:</h5>
1436<p>The label type represents code labels.</p>
1437
1438<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1439<pre>
1440 label
1441</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1442
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1443</div>
1444
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1445<!-- _______________________________________________________________________ -->
1446<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1447
1448<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1449
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1450<h5>Overview:</h5>
1451<p>The metadata type represents embedded metadata. The only derived type that
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1452 may contain metadata is <tt>metadata*</tt> or a function type that returns or
1453 takes metadata typed parameters, but not pointer to metadata types.</p>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1454
1455<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1456<pre>
1457 metadata
1458</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1459
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1460</div>
1461
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1462
1463<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1464<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1465
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1466<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1467
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1468<p>The real power in LLVM comes from the derived types in the system. This is
1469 what allows a programmer to represent arrays, functions, pointers, and other
1470 useful types. Note that these derived types may be recursive: For example,
1471 it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1472
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1473</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1474
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1475<!-- _______________________________________________________________________ -->
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1476<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1477
1478<div class="doc_text">
1479
1480<h5>Overview:</h5>
1481<p>The integer type is a very simple derived type that simply specifies an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1482 arbitrary bit width for the integer type desired. Any bit width from 1 bit to
1483 2^23-1 (about 8 million) can be specified.</p>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1484
1485<h5>Syntax:</h5>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1486<pre>
1487 iN
1488</pre>
1489
1490<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1491 value.</p>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1492
1493<h5>Examples:</h5>
1494<table class="layout">
Nick Lewyckyaab930a2009-05-24 02:46:06 +0000[diff] [blame]1495 <tr class="layout">
1496 <td class="left"><tt>i1</tt></td>
1497 <td class="left">a single-bit integer.</td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1498 </tr>
Nick Lewyckyaab930a2009-05-24 02:46:06 +0000[diff] [blame]1499 <tr class="layout">
1500 <td class="left"><tt>i32</tt></td>
1501 <td class="left">a 32-bit integer.</td>
1502 </tr>
1503 <tr class="layout">
1504 <td class="left"><tt>i1942652</tt></td>
1505 <td class="left">a really big integer of over 1 million bits.</td>
1506 </tr>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1507</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1508
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1509<p>Note that the code generator does not yet support large integer types to be
1510 used as function return types. The specific limit on how large a return type
1511 the code generator can currently handle is target-dependent; currently it's
1512 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1513
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1514</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1515
1516<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1517<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1518
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1519<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1520
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1521<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1522<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1523 sequentially in memory. The array type requires a size (number of elements)
1524 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1525
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1526<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1527<pre>
1528 [&lt;# elements&gt; x &lt;elementtype&gt;]
1529</pre>
1530
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1531<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1532 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1533
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1534<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1535<table class="layout">
1536 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1537 <td class="left"><tt>[40 x i32]</tt></td>
1538 <td class="left">Array of 40 32-bit integer values.</td>
1539 </tr>
1540 <tr class="layout">
1541 <td class="left"><tt>[41 x i32]</tt></td>
1542 <td class="left">Array of 41 32-bit integer values.</td>
1543 </tr>
1544 <tr class="layout">
1545 <td class="left"><tt>[4 x i8]</tt></td>
1546 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1547 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1548</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1549<p>Here are some examples of multidimensional arrays:</p>
1550<table class="layout">
1551 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1552 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1553 <td class="left">3x4 array of 32-bit integer values.</td>
1554 </tr>
1555 <tr class="layout">
1556 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1557 <td class="left">12x10 array of single precision floating point values.</td>
1558 </tr>
1559 <tr class="layout">
1560 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1561 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1562 </tr>
1563</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1564
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1565<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1566 length array. Normally, accesses past the end of an array are undefined in
1567 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1568 a special case, however, zero length arrays are recognized to be variable
1569 length. This allows implementation of 'pascal style arrays' with the LLVM
1570 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1571
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1572<p>Note that the code generator does not yet support large aggregate types to be
1573 used as function return types. The specific limit on how large an aggregate
1574 return type the code generator can currently handle is target-dependent, and
1575 also dependent on the aggregate element types.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1576
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1577</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1578
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1579<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1580<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1581
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1582<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1583
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1584<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1585<p>The function type can be thought of as a function signature. It consists of
1586 a return type and a list of formal parameter types. The return type of a
1587 function type is a scalar type, a void type, or a struct type. If the return
1588 type is a struct type then all struct elements must be of first class types,
1589 and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1590
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1591<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1592<pre>
1593 &lt;returntype list&gt; (&lt;parameter list&gt;)
1594</pre>
1595
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1596<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1597 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1598 which indicates that the function takes a variable number of arguments.
1599 Variable argument functions can access their arguments with
1600 the <a href="#int_varargs">variable argument handling intrinsic</a>
1601 functions. '<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1602 <a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1603
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1604<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1605<table class="layout">
1606 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1607 <td class="left"><tt>i32 (i32)</tt></td>
1608 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1609 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1610 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1611 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1612 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1613 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1614 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1615 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1616 <tt>float</tt>.
1617 </td>
1618 </tr><tr class="layout">
1619 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1620 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1621 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1622 which returns an integer. This is the signature for <tt>printf</tt> in
1623 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1624 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1625 </tr><tr class="layout">
1626 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanc9813bd2008-11-27 06:41:20 +0000[diff] [blame]1627 <td class="left">A function taking an <tt>i32</tt>, returning two
1628 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1629 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1630 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1631</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1632
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1633</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1634
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1635<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1636<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1637
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1638<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1639
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1640<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1641<p>The structure type is used to represent a collection of data members together
1642 in memory. The packing of the field types is defined to match the ABI of the
1643 underlying processor. The elements of a structure may be any type that has a
1644 size.</p>
1645
1646<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1647 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1648 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1649
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1650<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1651<pre>
1652 { &lt;type list&gt; }
1653</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1654
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1655<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1656<table class="layout">
1657 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1658 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1659 <td class="left">A triple of three <tt>i32</tt> values</td>
1660 </tr><tr class="layout">
1661 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1662 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1663 second element is a <a href="#t_pointer">pointer</a> to a
1664 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1665 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1666 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1667</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1668
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1669<p>Note that the code generator does not yet support large aggregate types to be
1670 used as function return types. The specific limit on how large an aggregate
1671 return type the code generator can currently handle is target-dependent, and
1672 also dependent on the aggregate element types.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1673
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1674</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1675
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1676<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1677<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1678</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1679
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1680<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1681
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1682<h5>Overview:</h5>
1683<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1684 together in memory. There is no padding between fields. Further, the
1685 alignment of a packed structure is 1 byte. The elements of a packed
1686 structure may be any type that has a size.</p>
1687
1688<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1689 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1690 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1691
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1692<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1693<pre>
1694 &lt; { &lt;type list&gt; } &gt;
1695</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1696
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1697<h5>Examples:</h5>
1698<table class="layout">
1699 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1700 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1701 <td class="left">A triple of three <tt>i32</tt> values</td>
1702 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1703 <td class="left">
1704<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1705 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1706 second element is a <a href="#t_pointer">pointer</a> to a
1707 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1708 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1709 </tr>
1710</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1711
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1712</div>
1713
1714<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1715<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1716
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1717<div class="doc_text">
1718
1719<h5>Overview:</h5>
1720<p>As in many languages, the pointer type represents a pointer or reference to
1721 another object, which must live in memory. Pointer types may have an optional
1722 address space attribute defining the target-specific numbered address space
1723 where the pointed-to object resides. The default address space is zero.</p>
1724
1725<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1726 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1727
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1728<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1729<pre>
1730 &lt;type&gt; *
1731</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1732
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1733<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1734<table class="layout">
1735 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1736 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1737 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1738 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1739 </tr>
1740 <tr class="layout">
1741 <td class="left"><tt>i32 (i32 *) *</tt></td>
1742 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1743 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1744 <tt>i32</tt>.</td>
1745 </tr>
1746 <tr class="layout">
1747 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1748 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1749 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1750 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1751</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1752
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1753</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1754
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1755<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1756<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1757
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1758<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1759
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1760<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1761<p>A vector type is a simple derived type that represents a vector of elements.
1762 Vector types are used when multiple primitive data are operated in parallel
1763 using a single instruction (SIMD). A vector type requires a size (number of
1764 elements) and an underlying primitive data type. Vectors must have a power
1765 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1766 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1767
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1768<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1769<pre>
1770 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1771</pre>
1772
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1773<p>The number of elements is a constant integer value; elementtype may be any
1774 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1775
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1776<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1777<table class="layout">
1778 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1779 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1780 <td class="left">Vector of 4 32-bit integer values.</td>
1781 </tr>
1782 <tr class="layout">
1783 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1784 <td class="left">Vector of 8 32-bit floating-point values.</td>
1785 </tr>
1786 <tr class="layout">
1787 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1788 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1789 </tr>
1790</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1791
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1792<p>Note that the code generator does not yet support large vector types to be
1793 used as function return types. The specific limit on how large a vector
1794 return type codegen can currently handle is target-dependent; currently it's
1795 often a few times longer than a hardware vector register.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1796
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1797</div>
1798
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1799<!-- _______________________________________________________________________ -->
1800<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1801<div class="doc_text">
1802
1803<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1804<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1805 corresponds (for example) to the C notion of a forward declared structure
1806 type. In LLVM, opaque types can eventually be resolved to any type (not just
1807 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1808
1809<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1810<pre>
1811 opaque
1812</pre>
1813
1814<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1815<table class="layout">
1816 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1817 <td class="left"><tt>opaque</tt></td>
1818 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1819 </tr>
1820</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1821
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1822</div>
1823
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1824<!-- ======================================================================= -->
1825<div class="doc_subsection">
1826 <a name="t_uprefs">Type Up-references</a>
1827</div>
1828
1829<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1830
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1831<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1832<p>An "up reference" allows you to refer to a lexically enclosing type without
1833 requiring it to have a name. For instance, a structure declaration may
1834 contain a pointer to any of the types it is lexically a member of. Example
1835 of up references (with their equivalent as named type declarations)
1836 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1837
1838<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1839 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1840 { \2 }* %y = type { %y }*
1841 \1* %z = type %z*
1842</pre>
1843
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1844<p>An up reference is needed by the asmprinter for printing out cyclic types
1845 when there is no declared name for a type in the cycle. Because the
1846 asmprinter does not want to print out an infinite type string, it needs a
1847 syntax to handle recursive types that have no names (all names are optional
1848 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1849
1850<h5>Syntax:</h5>
1851<pre>
1852 \&lt;level&gt;
1853</pre>
1854
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1855<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1856
1857<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1858<table class="layout">
1859 <tr class="layout">
1860 <td class="left"><tt>\1*</tt></td>
1861 <td class="left">Self-referential pointer.</td>
1862 </tr>
1863 <tr class="layout">
1864 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1865 <td class="left">Recursive structure where the upref refers to the out-most
1866 structure.</td>
1867 </tr>
1868</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1869
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1870</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1871
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1872<!-- *********************************************************************** -->
1873<div class="doc_section"> <a name="constants">Constants</a> </div>
1874<!-- *********************************************************************** -->
1875
1876<div class="doc_text">
1877
1878<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1879 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1880
1881</div>
1882
1883<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1884<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1885
1886<div class="doc_text">
1887
1888<dl>
1889 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1890 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1891 constants of the <tt><a href="#t_primitive">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1892
1893 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1894 <dd>Standard integers (such as '4') are constants of
1895 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1896 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1897
1898 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1899 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1900 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1901 notation (see below). The assembler requires the exact decimal value of a
1902 floating-point constant. For example, the assembler accepts 1.25 but
1903 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1904 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1905
1906 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1907 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1908 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1909</dl>
1910
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1911<p>The one non-intuitive notation for constants is the hexadecimal form of
1912 floating point constants. For example, the form '<tt>double
1913 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1914 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1915 constants are required (and the only time that they are generated by the
1916 disassembler) is when a floating point constant must be emitted but it cannot
1917 be represented as a decimal floating point number in a reasonable number of
1918 digits. For example, NaN's, infinities, and other special values are
1919 represented in their IEEE hexadecimal format so that assembly and disassembly
1920 do not cause any bits to change in the constants.</p>
1921
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]1922<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1923 represented using the 16-digit form shown above (which matches the IEEE754
1924 representation for double); float values must, however, be exactly
1925 representable as IEE754 single precision. Hexadecimal format is always used
1926 for long double, and there are three forms of long double. The 80-bit format
1927 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1928 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1929 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1930 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1931 currently supported target uses this format. Long doubles will only work if
1932 they match the long double format on your target. All hexadecimal formats
1933 are big-endian (sign bit at the left).</p>
1934
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1935</div>
1936
1937<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]1938<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]1939<a name="aggregateconstants"></a> <!-- old anchor -->
1940<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1941</div>
1942
1943<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1944
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]1945<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1946 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1947
1948<dl>
1949 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1950 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1951 type definitions (a comma separated list of elements, surrounded by braces
1952 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1953 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1954 Structure constants must have <a href="#t_struct">structure type</a>, and
1955 the number and types of elements must match those specified by the
1956 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1957
1958 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1959 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1960 definitions (a comma separated list of elements, surrounded by square
1961 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1962 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1963 the number and types of elements must match those specified by the
1964 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1965
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1966 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1967 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1968 definitions (a comma separated list of elements, surrounded by
1969 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1970 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1971 have <a href="#t_vector">vector type</a>, and the number and types of
1972 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1973
1974 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1975 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1976 value to zero of <em>any</em> type, including scalar and aggregate types.
1977 This is often used to avoid having to print large zero initializers
1978 (e.g. for large arrays) and is always exactly equivalent to using explicit
1979 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]1980
1981 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]1982 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1983 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1984 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1985 be interpreted as part of the instruction stream, metadata is a place to
1986 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1987</dl>
1988
1989</div>
1990
1991<!-- ======================================================================= -->
1992<div class="doc_subsection">
1993 <a name="globalconstants">Global Variable and Function Addresses</a>
1994</div>
1995
1996<div class="doc_text">
1997
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1998<p>The addresses of <a href="#globalvars">global variables</a>
1999 and <a href="#functionstructure">functions</a> are always implicitly valid
2000 (link-time) constants. These constants are explicitly referenced when
2001 the <a href="#identifiers">identifier for the global</a> is used and always
2002 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2003 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2004
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2005<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2006<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2007@X = global i32 17
2008@Y = global i32 42
2009@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2010</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2011</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2012
2013</div>
2014
2015<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2016<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2017<div class="doc_text">
2018
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2019<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
2020 indicates that the user of the value may recieve an unspecified bit-pattern.
2021 Undefined values may be of any type (other than label or void) and be used
2022 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2023
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2024<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2025 program is well defined no matter what value is used. This gives the
2026 compiler more freedom to optimize. Here are some examples of (potentially
2027 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2028
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2029
2030<div class="doc_code">
2031<pre>
2032 %A = add %X, undef
2033 %B = sub %X, undef
2034 %C = xor %X, undef
2035Safe:
2036 %A = undef
2037 %B = undef
2038 %C = undef
2039</pre>
2040</div>
2041
2042<p>This is safe because all of the output bits are affected by the undef bits.
2043Any output bit can have a zero or one depending on the input bits.</p>
2044
2045<div class="doc_code">
2046<pre>
2047 %A = or %X, undef
2048 %B = and %X, undef
2049Safe:
2050 %A = -1
2051 %B = 0
2052Unsafe:
2053 %A = undef
2054 %B = undef
2055</pre>
2056</div>
2057
2058<p>These logical operations have bits that are not always affected by the input.
2059For example, if "%X" has a zero bit, then the output of the 'and' operation will
2060always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2061such, it is unsafe to optimize or assume that the result of the and is undef.
2062However, it is safe to assume that all bits of the undef could be 0, and
2063optimize the and to 0. Likewise, it is safe to assume that all the bits of
2064the undef operand to the or could be set, allowing the or to be folded to
2065-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2066
2067<div class="doc_code">
2068<pre>
2069 %A = select undef, %X, %Y
2070 %B = select undef, 42, %Y
2071 %C = select %X, %Y, undef
2072Safe:
2073 %A = %X (or %Y)
2074 %B = 42 (or %Y)
2075 %C = %Y
2076Unsafe:
2077 %A = undef
2078 %B = undef
2079 %C = undef
2080</pre>
2081</div>
2082
2083<p>This set of examples show that undefined select (and conditional branch)
2084conditions can go "either way" but they have to come from one of the two
2085operands. In the %A example, if %X and %Y were both known to have a clear low
2086bit, then %A would have to have a cleared low bit. However, in the %C example,
2087the optimizer is allowed to assume that the undef operand could be the same as
2088%Y, allowing the whole select to be eliminated.</p>
2089
2090
2091<div class="doc_code">
2092<pre>
2093 %A = xor undef, undef
2094
2095 %B = undef
2096 %C = xor %B, %B
2097
2098 %D = undef
2099 %E = icmp lt %D, 4
2100 %F = icmp gte %D, 4
2101
2102Safe:
2103 %A = undef
2104 %B = undef
2105 %C = undef
2106 %D = undef
2107 %E = undef
2108 %F = undef
2109</pre>
2110</div>
2111
2112<p>This example points out that two undef operands are not necessarily the same.
2113This can be surprising to people (and also matches C semantics) where they
2114assume that "X^X" is always zero, even if X is undef. This isn't true for a
2115number of reasons, but the short answer is that an undef "variable" can
2116arbitrarily change its value over its "live range". This is true because the
2117"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2118logically read from arbitrary registers that happen to be around when needed,
2119so the value is not neccesarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2120to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2121would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2122
2123<div class="doc_code">
2124<pre>
2125 %A = fdiv undef, %X
2126 %B = fdiv %X, undef
2127Safe:
2128 %A = undef
2129b: unreachable
2130</pre>
2131</div>
2132
2133<p>These examples show the crucial difference between an <em>undefined
2134value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2135allowed to have an arbitrary bit-pattern. This means that the %A operation
2136can be constant folded to undef because the undef could be an SNaN, and fdiv is
2137not (currently) defined on SNaN's. However, in the second example, we can make
2138a more aggressive assumption: because the undef is allowed to be an arbitrary
2139value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner10ff0c12009-09-08 19:45:34 +0000[diff] [blame]2140has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2141does not execute at all. This allows us to delete the divide and all code after
2142it: since the undefined operation "can't happen", the optimizer can assume that
2143it occurs in dead code.
2144</p>
2145
2146<div class="doc_code">
2147<pre>
2148a: store undef -> %X
2149b: store %X -> undef
2150Safe:
2151a: &lt;deleted&gt;
2152b: unreachable
2153</pre>
2154</div>
2155
2156<p>These examples reiterate the fdiv example: a store "of" an undefined value
2157can be assumed to not have any effect: we can assume that the value is
2158overwritten with bits that happen to match what was already there. However, a
2159store "to" an undefined location could clobber arbitrary memory, therefore, it
2160has undefined behavior.</p>
2161
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2162</div>
2163
2164<!-- ======================================================================= -->
2165<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2166</div>
2167
2168<div class="doc_text">
2169
2170<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2171 to be used as constants. Constant expressions may be of
2172 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2173 operation that does not have side effects (e.g. load and call are not
2174 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2175
2176<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2177 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2178 <dd>Truncate a constant to another type. The bit size of CST must be larger
2179 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2180
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2181 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2182 <dd>Zero extend a constant to another type. The bit size of CST must be
2183 smaller or equal to the bit size of TYPE. Both types must be
2184 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2185
2186 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2187 <dd>Sign extend a constant to another type. The bit size of CST must be
2188 smaller or equal to the bit size of TYPE. Both types must be
2189 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2190
2191 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2192 <dd>Truncate a floating point constant to another floating point type. The
2193 size of CST must be larger than the size of TYPE. Both types must be
2194 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2195
2196 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2197 <dd>Floating point extend a constant to another type. The size of CST must be
2198 smaller or equal to the size of TYPE. Both types must be floating
2199 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2200
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]2201 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2202 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2203 constant. TYPE must be a scalar or vector integer type. CST must be of
2204 scalar or vector floating point type. Both CST and TYPE must be scalars,
2205 or vectors of the same number of elements. If the value won't fit in the
2206 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2207
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2208 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2209 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2210 constant. TYPE must be a scalar or vector integer type. CST must be of
2211 scalar or vector floating point type. Both CST and TYPE must be scalars,
2212 or vectors of the same number of elements. If the value won't fit in the
2213 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2214
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2215 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2216 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2217 constant. TYPE must be a scalar or vector floating point type. CST must be
2218 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2219 vectors of the same number of elements. If the value won't fit in the
2220 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2221
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2222 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2223 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2224 constant. TYPE must be a scalar or vector floating point type. CST must be
2225 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2226 vectors of the same number of elements. If the value won't fit in the
2227 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2228
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2229 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2230 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2231 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2232 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2233 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2234
2235 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2236 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2237 type. CST must be of integer type. The CST value is zero extended,
2238 truncated, or unchanged to make it fit in a pointer size. This one is
2239 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2240
2241 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2242 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2243 are the same as those for the <a href="#i_bitcast">bitcast
2244 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2245
2246 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]2247 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2248 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2249 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2250 instruction, the index list may have zero or more indexes, which are
2251 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2252
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2253 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2254 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2255
2256 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2257 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2258
2259 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2260 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2261
2262 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2263 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2264 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2265
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]2266 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2267 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2268 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2269
2270 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2271 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2272 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2273
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2274 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2275 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2276 be any of the <a href="#binaryops">binary</a>
2277 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2278 on operands are the same as those for the corresponding instruction
2279 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2280</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2281
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2282</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2283
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2284<!-- ======================================================================= -->
2285<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2286</div>
2287
2288<div class="doc_text">
2289
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2290<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2291 stream without affecting the behaviour of the program. There are two
2292 metadata primitives, strings and nodes. All metadata has the
2293 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2294 point ('<tt>!</tt>').</p>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2295
2296<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2297 any character by escaping non-printable characters with "\xx" where "xx" is
2298 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2299
2300<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2301 (a comma separated list of elements, surrounded by braces and preceeded by an
2302 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2303 10}</tt>".</p>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2304
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2305<p>A metadata node will attempt to track changes to the values it holds. In the
2306 event that a value is deleted, it will be replaced with a typeless
2307 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckyb8f9b7a2009-05-10 20:57:05 +0000[diff] [blame]2308
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2309<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2310 the program that isn't available in the instructions, or that isn't easily
2311 computable. Similarly, the code generator may expect a certain metadata
2312 format to be used to express debugging information.</p>
2313
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2314</div>
2315
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2316<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2317<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2318<!-- *********************************************************************** -->
2319
2320<!-- ======================================================================= -->
2321<div class="doc_subsection">
2322<a name="inlineasm">Inline Assembler Expressions</a>
2323</div>
2324
2325<div class="doc_text">
2326
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2327<p>LLVM supports inline assembler expressions (as opposed
2328 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2329 a special value. This value represents the inline assembler as a string
2330 (containing the instructions to emit), a list of operand constraints (stored
2331 as a string), and a flag that indicates whether or not the inline asm
2332 expression has side effects. An example inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2333
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2334<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2335<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2336i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2337</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2338</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2339
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2340<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2341 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2342 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2343
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2344<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2345<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2346%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2347</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2348</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2349
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2350<p>Inline asms with side effects not visible in the constraint list must be
2351 marked as having side effects. This is done through the use of the
2352 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2353
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2354<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2355<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2356call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2357</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2358</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2359
2360<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2361 documented here. Constraints on what can be done (e.g. duplication, moving,
2362 etc need to be documented). This is probably best done by reference to
2363 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2364
2365</div>
2366
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2367
2368<!-- *********************************************************************** -->
2369<div class="doc_section">
2370 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2371</div>
2372<!-- *********************************************************************** -->
2373
2374<p>LLVM has a number of "magic" global variables that contain data that affect
2375code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2376of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2377section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2378by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2379
2380<!-- ======================================================================= -->
2381<div class="doc_subsection">
2382<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2383</div>
2384
2385<div class="doc_text">
2386
2387<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2388href="#linkage_appending">appending linkage</a>. This array contains a list of
2389pointers to global variables and functions which may optionally have a pointer
2390cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2391
2392<pre>
2393 @X = global i8 4
2394 @Y = global i32 123
2395
2396 @llvm.used = appending global [2 x i8*] [
2397 i8* @X,
2398 i8* bitcast (i32* @Y to i8*)
2399 ], section "llvm.metadata"
2400</pre>
2401
2402<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2403compiler, assembler, and linker are required to treat the symbol as if there is
2404a reference to the global that it cannot see. For example, if a variable has
2405internal linkage and no references other than that from the <tt>@llvm.used</tt>
2406list, it cannot be deleted. This is commonly used to represent references from
2407inline asms and other things the compiler cannot "see", and corresponds to
2408"attribute((used))" in GNU C.</p>
2409
2410<p>On some targets, the code generator must emit a directive to the assembler or
2411object file to prevent the assembler and linker from molesting the symbol.</p>
2412
2413</div>
2414
2415<!-- ======================================================================= -->
2416<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2417<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2418</div>
2419
2420<div class="doc_text">
2421
2422<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2423<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2424touching the symbol. On targets that support it, this allows an intelligent
2425linker to optimize references to the symbol without being impeded as it would be
2426by <tt>@llvm.used</tt>.</p>
2427
2428<p>This is a rare construct that should only be used in rare circumstances, and
2429should not be exposed to source languages.</p>
2430
2431</div>
2432
2433<!-- ======================================================================= -->
2434<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2435<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2436</div>
2437
2438<div class="doc_text">
2439
2440<p>TODO: Describe this.</p>
2441
2442</div>
2443
2444<!-- ======================================================================= -->
2445<div class="doc_subsection">
2446<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2447</div>
2448
2449<div class="doc_text">
2450
2451<p>TODO: Describe this.</p>
2452
2453</div>
2454
2455
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2456<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2457<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2458<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2459
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2460<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2461
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2462<p>The LLVM instruction set consists of several different classifications of
2463 instructions: <a href="#terminators">terminator
2464 instructions</a>, <a href="#binaryops">binary instructions</a>,
2465 <a href="#bitwiseops">bitwise binary instructions</a>,
2466 <a href="#memoryops">memory instructions</a>, and
2467 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2468
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2469</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2470
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2471<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2472<div class="doc_subsection"> <a name="terminators">Terminator
2473Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2474
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2475<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2476
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2477<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2478 in a program ends with a "Terminator" instruction, which indicates which
2479 block should be executed after the current block is finished. These
2480 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2481 control flow, not values (the one exception being the
2482 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2483
2484<p>There are six different terminator instructions: the
2485 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2486 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2487 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2488 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2489 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2490 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2491
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2492</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2493
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2494<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2495<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2496Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2497
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2498<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2499
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2500<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2501<pre>
2502 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2503 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2504</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2505
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2506<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2507<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2508 a value) from a function back to the caller.</p>
2509
2510<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2511 value and then causes control flow, and one that just causes control flow to
2512 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2513
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2514<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2515<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2516 return value. The type of the return value must be a
2517 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2518
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2519<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2520 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2521 value or a return value with a type that does not match its type, or if it
2522 has a void return type and contains a '<tt>ret</tt>' instruction with a
2523 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2524
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2525<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2526<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2527 the calling function's context. If the caller is a
2528 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2529 instruction after the call. If the caller was an
2530 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2531 the beginning of the "normal" destination block. If the instruction returns
2532 a value, that value shall set the call or invoke instruction's return
2533 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2534
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2535<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2536<pre>
2537 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2538 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2539 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2540</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2541
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2542<p>Note that the code generator does not yet fully support large
2543 return values. The specific sizes that are currently supported are
2544 dependent on the target. For integers, on 32-bit targets the limit
2545 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2546 For aggregate types, the current limits are dependent on the element
2547 types; for example targets are often limited to 2 total integer
2548 elements and 2 total floating-point elements.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2549
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2550</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2551<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2552<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2553
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2554<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2555
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2556<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2557<pre>
2558 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2559</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2560
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2561<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2562<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2563 different basic block in the current function. There are two forms of this
2564 instruction, corresponding to a conditional branch and an unconditional
2565 branch.</p>
2566
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2567<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2568<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2569 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2570 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2571 target.</p>
2572
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2573<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2574<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2575 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2576 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2577 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2578
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2579<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2580<pre>
2581Test:
2582 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2583 br i1 %cond, label %IfEqual, label %IfUnequal
2584IfEqual:
2585 <a href="#i_ret">ret</a> i32 1
2586IfUnequal:
2587 <a href="#i_ret">ret</a> i32 0
2588</pre>
2589
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2590</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2591
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2592<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2593<div class="doc_subsubsection">
2594 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2595</div>
2596
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2597<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2598
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2599<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2600<pre>
2601 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2602</pre>
2603
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2604<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2605<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2606 several different places. It is a generalization of the '<tt>br</tt>'
2607 instruction, allowing a branch to occur to one of many possible
2608 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2609
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2610<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2611<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2612 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2613 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2614 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2615
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2616<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2617<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2618 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2619 is searched for the given value. If the value is found, control flow is
2620 transfered to the corresponding destination; otherwise, control flow is
2621 transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2622
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2623<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2624<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2625 <tt>switch</tt> instruction, this instruction may be code generated in
2626 different ways. For example, it could be generated as a series of chained
2627 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2628
2629<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2630<pre>
2631 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2632 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2633 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2634
2635 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2636 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2637
2638 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2639 switch i32 %val, label %otherwise [ i32 0, label %onzero
2640 i32 1, label %onone
2641 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2642</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2643
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2644</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2645
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2646<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2647<div class="doc_subsubsection">
2648 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2649</div>
2650
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2651<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2652
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2653<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2654<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2655 &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 Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]2656 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2657</pre>
2658
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2659<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2660<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2661 function, with the possibility of control flow transfer to either the
2662 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2663 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2664 control flow will return to the "normal" label. If the callee (or any
2665 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2666 instruction, control is interrupted and continued at the dynamically nearest
2667 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2668
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2669<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2670<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2671
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2672<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2673 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2674 convention</a> the call should use. If none is specified, the call
2675 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2676
2677 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2678 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2679 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2680
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2681 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2682 function value being invoked. In most cases, this is a direct function
2683 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2684 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2685
2686 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2687 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2688
2689 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2690 signature argument types. If the function signature indicates the
2691 function accepts a variable number of arguments, the extra arguments can
2692 be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2693
2694 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2695 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2696
2697 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2698 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2699
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2700 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2701 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2702 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2703</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2704
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2705<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2706<p>This instruction is designed to operate as a standard
2707 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2708 primary difference is that it establishes an association with a label, which
2709 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2710
2711<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2712 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2713 exception. Additionally, this is important for implementation of
2714 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2715
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2716<p>For the purposes of the SSA form, the definition of the value returned by the
2717 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2718 block to the "normal" label. If the callee unwinds then no return value is
2719 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]2720
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2721<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2722<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2723 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2724 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2725 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2726 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2727</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2728
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2729</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2730
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2731<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2732
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2733<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2734Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2735
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2736<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2737
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2738<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2739<pre>
2740 unwind
2741</pre>
2742
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2743<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2744<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2745 at the first callee in the dynamic call stack which used
2746 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2747 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2748
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2749<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2750<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2751 immediately halt. The dynamic call stack is then searched for the
2752 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2753 Once found, execution continues at the "exceptional" destination block
2754 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2755 instruction in the dynamic call chain, undefined behavior results.</p>
2756
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2757</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2758
2759<!-- _______________________________________________________________________ -->
2760
2761<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2762Instruction</a> </div>
2763
2764<div class="doc_text">
2765
2766<h5>Syntax:</h5>
2767<pre>
2768 unreachable
2769</pre>
2770
2771<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2772<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2773 instruction is used to inform the optimizer that a particular portion of the
2774 code is not reachable. This can be used to indicate that the code after a
2775 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2776
2777<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2778<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2779
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2780</div>
2781
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2782<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2783<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2784
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2785<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2786
2787<p>Binary operators are used to do most of the computation in a program. They
2788 require two operands of the same type, execute an operation on them, and
2789 produce a single value. The operands might represent multiple data, as is
2790 the case with the <a href="#t_vector">vector</a> data type. The result value
2791 has the same type as its operands.</p>
2792
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2793<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2794
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2795</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2796
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2797<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2798<div class="doc_subsubsection">
2799 <a name="i_add">'<tt>add</tt>' Instruction</a>
2800</div>
2801
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2802<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2803
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2804<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2805<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]2806 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]2807 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2808 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2809 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2810</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2811
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2812<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2813<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2814
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2815<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2816<p>The two arguments to the '<tt>add</tt>' instruction must
2817 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2818 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2819
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2820<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2821<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2822
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2823<p>If the sum has unsigned overflow, the result returned is the mathematical
2824 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2825
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2826<p>Because LLVM integers use a two's complement representation, this instruction
2827 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2828
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2829<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2830 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2831 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2832 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]2833
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2834<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2835<pre>
2836 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2837</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2838
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2839</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2840
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2841<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2842<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2843 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2844</div>
2845
2846<div class="doc_text">
2847
2848<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2849<pre>
2850 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2851</pre>
2852
2853<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2854<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2855
2856<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2857<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2858 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2859 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2860
2861<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2862<p>The value produced is the floating point sum of the two operands.</p>
2863
2864<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2865<pre>
2866 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2867</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2868
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2869</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2870
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2871<!-- _______________________________________________________________________ -->
2872<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2873 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2874</div>
2875
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2876<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2877
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2878<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2879<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2880 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]2881 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2882 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2883 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2884</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2885
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2886<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2887<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2888 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2889
2890<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2891 '<tt>neg</tt>' instruction present in most other intermediate
2892 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2893
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2894<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2895<p>The two arguments to the '<tt>sub</tt>' instruction must
2896 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2897 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2898
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2899<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2900<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2901
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2902<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2903 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2904 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2905
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2906<p>Because LLVM integers use a two's complement representation, this instruction
2907 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2908
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2909<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2910 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2911 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2912 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]2913
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2914<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2915<pre>
2916 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2917 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2918</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2919
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2920</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2921
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2922<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2923<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2924 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2925</div>
2926
2927<div class="doc_text">
2928
2929<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2930<pre>
2931 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2932</pre>
2933
2934<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2935<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2936 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2937
2938<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2939 '<tt>fneg</tt>' instruction present in most other intermediate
2940 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2941
2942<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2943<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2944 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2945 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2946
2947<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2948<p>The value produced is the floating point difference of the two operands.</p>
2949
2950<h5>Example:</h5>
2951<pre>
2952 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2953 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2954</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2955
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2956</div>
2957
2958<!-- _______________________________________________________________________ -->
2959<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2960 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2961</div>
2962
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2963<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2964
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2965<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2966<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2967 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]2968 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2969 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2970 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2971</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2972
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2973<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2974<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2975
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2976<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2977<p>The two arguments to the '<tt>mul</tt>' instruction must
2978 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2979 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2980
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2981<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2982<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2983
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2984<p>If the result of the multiplication has unsigned overflow, the result
2985 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2986 width of the result.</p>
2987
2988<p>Because LLVM integers use a two's complement representation, and the result
2989 is the same width as the operands, this instruction returns the correct
2990 result for both signed and unsigned integers. If a full product
2991 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2992 be sign-extended or zero-extended as appropriate to the width of the full
2993 product.</p>
2994
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2995<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2996 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2997 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
2998 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]2999
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3000<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3001<pre>
3002 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3003</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3004
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3005</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3006
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3007<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3008<div class="doc_subsubsection">
3009 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3010</div>
3011
3012<div class="doc_text">
3013
3014<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3015<pre>
3016 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3017</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3018
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3019<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3020<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3021
3022<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3023<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3024 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3025 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3026
3027<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3028<p>The value produced is the floating point product of the two operands.</p>
3029
3030<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3031<pre>
3032 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3033</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3034
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3035</div>
3036
3037<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3038<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3039</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3040
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3041<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3042
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3043<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3044<pre>
3045 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3046</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3047
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3048<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3049<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3050
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3051<h5>Arguments:</h5>
3052<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3053 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3054 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3055
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3056<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3057<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3058
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3059<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3060 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3061
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3062<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3063
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3064<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3065<pre>
3066 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3067</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3068
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3069</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3070
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3071<!-- _______________________________________________________________________ -->
3072<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3073</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3074
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3075<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3076
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3077<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3078<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3079 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3080 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3081</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3082
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3083<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3084<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3085
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3086<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3087<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3088 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3089 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3090
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3091<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3092<p>The value produced is the signed integer quotient of the two operands rounded
3093 towards zero.</p>
3094
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3095<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3096 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3097
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3098<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3099 undefined behavior; this is a rare case, but can occur, for example, by doing
3100 a 32-bit division of -2147483648 by -1.</p>
3101
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3102<p>If the <tt>exact</tt> keyword is present, the result value of the
3103 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3104 would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3105
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3106<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3107<pre>
3108 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3109</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3110
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3111</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3112
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3113<!-- _______________________________________________________________________ -->
3114<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3115Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3116
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3117<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3118
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3119<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3120<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3121 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3122</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3123
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3124<h5>Overview:</h5>
3125<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3126
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3127<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3128<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3129 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3130 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3131
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3132<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3133<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3134
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3135<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3136<pre>
3137 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3138</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3139
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3140</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3141
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3142<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3143<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3144</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3145
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3146<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3147
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3148<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3149<pre>
3150 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3151</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3152
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3153<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3154<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3155 division of its two arguments.</p>
3156
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3157<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3158<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3159 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3160 values. Both arguments must have identical types.</p>
3161
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3162<h5>Semantics:</h5>
3163<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3164 This instruction always performs an unsigned division to get the
3165 remainder.</p>
3166
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3167<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3168 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3169
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3170<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3171
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3172<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3173<pre>
3174 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3175</pre>
3176
3177</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3178
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3179<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3180<div class="doc_subsubsection">
3181 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3182</div>
3183
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3184<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3185
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3186<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3187<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3188 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3189</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3190
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3191<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3192<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3193 division of its two operands. This instruction can also take
3194 <a href="#t_vector">vector</a> versions of the values in which case the
3195 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3196
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3197<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3198<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3199 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3200 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3201
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3202<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3203<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3204 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3205 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3206 a value. For more information about the difference,
3207 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3208 Math Forum</a>. For a table of how this is implemented in various languages,
3209 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3210 Wikipedia: modulo operation</a>.</p>
3211
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3212<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3213 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3214
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3215<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3216 Overflow also leads to undefined behavior; this is a rare case, but can
3217 occur, for example, by taking the remainder of a 32-bit division of
3218 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3219 lets srem be implemented using instructions that return both the result of
3220 the division and the remainder.)</p>
3221
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3222<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3223<pre>
3224 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3225</pre>
3226
3227</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3228
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3229<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3230<div class="doc_subsubsection">
3231 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3232
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3233<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3234
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3235<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3236<pre>
3237 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3238</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3239
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3240<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3241<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3242 its two operands.</p>
3243
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3244<h5>Arguments:</h5>
3245<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3246 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3247 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3248
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3249<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3250<p>This instruction returns the <i>remainder</i> of a division. The remainder
3251 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3252
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3253<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3254<pre>
3255 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3256</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3257
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3258</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3259
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3260<!-- ======================================================================= -->
3261<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3262Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3263
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3264<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3265
3266<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3267 program. They are generally very efficient instructions and can commonly be
3268 strength reduced from other instructions. They require two operands of the
3269 same type, execute an operation on them, and produce a single value. The
3270 resulting value is the same type as its operands.</p>
3271
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3272</div>
3273
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3274<!-- _______________________________________________________________________ -->
3275<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3276Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3277
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3278<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3279
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3280<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3281<pre>
3282 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3283</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3284
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3285<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3286<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3287 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3288
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3289<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3290<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3291 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3292 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3293
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3294<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3295<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3296 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3297 is (statically or dynamically) negative or equal to or larger than the number
3298 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3299 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3300 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3301
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3302<h5>Example:</h5>
3303<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3304 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3305 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3306 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3307 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3308 &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 Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3309</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3310
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3311</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3312
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3313<!-- _______________________________________________________________________ -->
3314<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3315Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3316
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3317<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3318
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3319<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3320<pre>
3321 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3322</pre>
3323
3324<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3325<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3326 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3327
3328<h5>Arguments:</h5>
3329<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3330 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3331 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3332
3333<h5>Semantics:</h5>
3334<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3335 significant bits of the result will be filled with zero bits after the shift.
3336 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3337 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3338 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3339 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3340
3341<h5>Example:</h5>
3342<pre>
3343 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3344 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3345 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3346 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3347 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3348 &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 Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3349</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3350
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3351</div>
3352
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3353<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3354<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3355Instruction</a> </div>
3356<div class="doc_text">
3357
3358<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3359<pre>
3360 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3361</pre>
3362
3363<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3364<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3365 operand shifted to the right a specified number of bits with sign
3366 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3367
3368<h5>Arguments:</h5>
3369<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3370 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3371 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3372
3373<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3374<p>This instruction always performs an arithmetic shift right operation, The
3375 most significant bits of the result will be filled with the sign bit
3376 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3377 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3378 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3379 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3380
3381<h5>Example:</h5>
3382<pre>
3383 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3384 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3385 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3386 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3387 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3388 &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 Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3389</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3390
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3391</div>
3392
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3393<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3394<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3395Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3396
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3397<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3398
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3399<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3400<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3401 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3402</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3403
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3404<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3405<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3406 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3407
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3408<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3409<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3410 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3411 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3412
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3413<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3414<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3415
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3416<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3417 <tbody>
3418 <tr>
3419 <td>In0</td>
3420 <td>In1</td>
3421 <td>Out</td>
3422 </tr>
3423 <tr>
3424 <td>0</td>
3425 <td>0</td>
3426 <td>0</td>
3427 </tr>
3428 <tr>
3429 <td>0</td>
3430 <td>1</td>
3431 <td>0</td>
3432 </tr>
3433 <tr>
3434 <td>1</td>
3435 <td>0</td>
3436 <td>0</td>
3437 </tr>
3438 <tr>
3439 <td>1</td>
3440 <td>1</td>
3441 <td>1</td>
3442 </tr>
3443 </tbody>
3444</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3445
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3446<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3447<pre>
3448 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3449 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3450 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3451</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3452</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3453<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3454<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3455
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3456<div class="doc_text">
3457
3458<h5>Syntax:</h5>
3459<pre>
3460 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3461</pre>
3462
3463<h5>Overview:</h5>
3464<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3465 two operands.</p>
3466
3467<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3468<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3469 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3470 values. Both arguments must have identical types.</p>
3471
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3472<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3473<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3474
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3475<table border="1" cellspacing="0" cellpadding="4">
3476 <tbody>
3477 <tr>
3478 <td>In0</td>
3479 <td>In1</td>
3480 <td>Out</td>
3481 </tr>
3482 <tr>
3483 <td>0</td>
3484 <td>0</td>
3485 <td>0</td>
3486 </tr>
3487 <tr>
3488 <td>0</td>
3489 <td>1</td>
3490 <td>1</td>
3491 </tr>
3492 <tr>
3493 <td>1</td>
3494 <td>0</td>
3495 <td>1</td>
3496 </tr>
3497 <tr>
3498 <td>1</td>
3499 <td>1</td>
3500 <td>1</td>
3501 </tr>
3502 </tbody>
3503</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3504
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3505<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3506<pre>
3507 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3508 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3509 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3510</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3511
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3512</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3513
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3514<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3515<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3516Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3517
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3518<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3519
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3520<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3521<pre>
3522 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3523</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3524
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3525<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3526<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3527 its two operands. The <tt>xor</tt> is used to implement the "one's
3528 complement" operation, which is the "~" operator in C.</p>
3529
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3530<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3531<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3532 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3533 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3534
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3535<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3536<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3537
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3538<table border="1" cellspacing="0" cellpadding="4">
3539 <tbody>
3540 <tr>
3541 <td>In0</td>
3542 <td>In1</td>
3543 <td>Out</td>
3544 </tr>
3545 <tr>
3546 <td>0</td>
3547 <td>0</td>
3548 <td>0</td>
3549 </tr>
3550 <tr>
3551 <td>0</td>
3552 <td>1</td>
3553 <td>1</td>
3554 </tr>
3555 <tr>
3556 <td>1</td>
3557 <td>0</td>
3558 <td>1</td>
3559 </tr>
3560 <tr>
3561 <td>1</td>
3562 <td>1</td>
3563 <td>0</td>
3564 </tr>
3565 </tbody>
3566</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3567
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3568<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3569<pre>
3570 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3571 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3572 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3573 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3574</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3575
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3576</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3577
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3578<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3579<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3580 <a name="vectorops">Vector Operations</a>
3581</div>
3582
3583<div class="doc_text">
3584
3585<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3586 target-independent manner. These instructions cover the element-access and
3587 vector-specific operations needed to process vectors effectively. While LLVM
3588 does directly support these vector operations, many sophisticated algorithms
3589 will want to use target-specific intrinsics to take full advantage of a
3590 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3591
3592</div>
3593
3594<!-- _______________________________________________________________________ -->
3595<div class="doc_subsubsection">
3596 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3597</div>
3598
3599<div class="doc_text">
3600
3601<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3602<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3603 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3604</pre>
3605
3606<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3607<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3608 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3609
3610
3611<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3612<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3613 of <a href="#t_vector">vector</a> type. The second operand is an index
3614 indicating the position from which to extract the element. The index may be
3615 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3616
3617<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3618<p>The result is a scalar of the same type as the element type of
3619 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3620 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3621 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3622
3623<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3624<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3625 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3626</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3627
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3628</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3629
3630<!-- _______________________________________________________________________ -->
3631<div class="doc_subsubsection">
3632 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3633</div>
3634
3635<div class="doc_text">
3636
3637<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3638<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]3639 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3640</pre>
3641
3642<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3643<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3644 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3645
3646<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3647<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3648 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3649 whose type must equal the element type of the first operand. The third
3650 operand is an index indicating the position at which to insert the value.
3651 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3652
3653<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3654<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3655 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3656 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3657 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3658
3659<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3660<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3661 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3662</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3663
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3664</div>
3665
3666<!-- _______________________________________________________________________ -->
3667<div class="doc_subsubsection">
3668 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3669</div>
3670
3671<div class="doc_text">
3672
3673<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3674<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]3675 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3676</pre>
3677
3678<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3679<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3680 from two input vectors, returning a vector with the same element type as the
3681 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3682
3683<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3684<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3685 with types that match each other. The third argument is a shuffle mask whose
3686 element type is always 'i32'. The result of the instruction is a vector
3687 whose length is the same as the shuffle mask and whose element type is the
3688 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3689
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3690<p>The shuffle mask operand is required to be a constant vector with either
3691 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3692
3693<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3694<p>The elements of the two input vectors are numbered from left to right across
3695 both of the vectors. The shuffle mask operand specifies, for each element of
3696 the result vector, which element of the two input vectors the result element
3697 gets. The element selector may be undef (meaning "don't care") and the
3698 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3699
3700<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3701<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3702 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3703 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3704 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3705 &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 Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]3706 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3707 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3708 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3709 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3710</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3711
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3712</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]3713
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3714<!-- ======================================================================= -->
3715<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3716 <a name="aggregateops">Aggregate Operations</a>
3717</div>
3718
3719<div class="doc_text">
3720
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3721<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3722
3723</div>
3724
3725<!-- _______________________________________________________________________ -->
3726<div class="doc_subsubsection">
3727 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3728</div>
3729
3730<div class="doc_text">
3731
3732<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3733<pre>
3734 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3735</pre>
3736
3737<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3738<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3739 or array element from an aggregate value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3740
3741<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3742<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3743 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3744 operands are constant indices to specify which value to extract in a similar
3745 manner as indices in a
3746 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3747
3748<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3749<p>The result is the value at the position in the aggregate specified by the
3750 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3751
3752<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3753<pre>
Dan Gohman1ecaf452008-05-31 00:58:22 +0000[diff] [blame]3754 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3755</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3756
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3757</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3758
3759<!-- _______________________________________________________________________ -->
3760<div class="doc_subsubsection">
3761 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3762</div>
3763
3764<div class="doc_text">
3765
3766<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3767<pre>
Dan Gohman1ecaf452008-05-31 00:58:22 +0000[diff] [blame]3768 &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 Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3769</pre>
3770
3771<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3772<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3773 array element in an aggregate.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3774
3775
3776<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3777<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3778 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3779 second operand is a first-class value to insert. The following operands are
3780 constant indices indicating the position at which to insert the value in a
3781 similar manner as indices in a
3782 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3783 value to insert must have the same type as the value identified by the
3784 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3785
3786<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3787<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3788 that of <tt>val</tt> except that the value at the position specified by the
3789 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3790
3791<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3792<pre>
Dan Gohman88ce1a52008-06-23 15:26:37 +0000[diff] [blame]3793 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3794</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3795
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3796</div>
3797
3798
3799<!-- ======================================================================= -->
3800<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]3801 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3802</div>
3803
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3804<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3805
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3806<p>A key design point of an SSA-based representation is how it represents
3807 memory. In LLVM, no memory locations are in SSA form, which makes things
3808 very simple. This section describes how to read, write, allocate, and free
3809 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3810
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3811</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3812
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3813<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3814<div class="doc_subsubsection">
3815 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3816</div>
3817
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3818<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3819
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3820<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3821<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3822 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3823</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3824
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3825<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3826<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3827 returns a pointer to it. The object is always allocated in the generic
3828 address space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3829
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3830<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3831<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3832 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3833 system and returns a pointer of the appropriate type to the program. If
3834 "NumElements" is specified, it is the number of elements allocated, otherwise
3835 "NumElements" is defaulted to be one. If a constant alignment is specified,
3836 the value result of the allocation is guaranteed to be aligned to at least
3837 that boundary. If not specified, or if zero, the target can choose to align
3838 the allocation on any convenient boundary compatible with the type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3839
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3840<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3841
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3842<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3843<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3844 pointer is returned. The result of a zero byte allocation is undefined. The
3845 result is null if there is insufficient memory available.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3846
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3847<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3848<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]3849 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3850
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3851 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3852 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3853 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3854 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3855 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3856</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3857
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3858<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3859
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3860</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3861
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3862<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3863<div class="doc_subsubsection">
3864 <a name="i_free">'<tt>free</tt>' Instruction</a>
3865</div>
3866
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3867<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3868
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3869<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3870<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]3871 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3872</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3873
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3874<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3875<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3876 to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3877
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3878<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3879<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3880 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3881
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3882<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3883<p>Access to the memory pointed to by the pointer is no longer defined after
3884 this instruction executes. If the pointer is null, the operation is a
3885 noop.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3886
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3887<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3888<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]3889 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3890 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3891</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3892
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3893</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3894
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3895<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3896<div class="doc_subsubsection">
3897 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3898</div>
3899
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3900<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3901
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3902<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3903<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3904 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3905</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3906
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3907<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3908<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3909 currently executing function, to be automatically released when this function
3910 returns to its caller. The object is always allocated in the generic address
3911 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3912
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3913<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3914<p>The '<tt>alloca</tt>' instruction
3915 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3916 runtime stack, returning a pointer of the appropriate type to the program.
3917 If "NumElements" is specified, it is the number of elements allocated,
3918 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3919 specified, the value result of the allocation is guaranteed to be aligned to
3920 at least that boundary. If not specified, or if zero, the target can choose
3921 to align the allocation on any convenient boundary compatible with the
3922 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3923
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3924<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3925
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3926<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]3927<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3928 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3929 memory is automatically released when the function returns. The
3930 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3931 variables that must have an address available. When the function returns
3932 (either with the <tt><a href="#i_ret">ret</a></tt>
3933 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3934 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3935
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3936<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3937<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]3938 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3939 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3940 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3941 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3942</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3943
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3944</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3945
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3946<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3947<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3948Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3949
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3950<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3951
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3952<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3953<pre>
3954 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3955 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3956</pre>
3957
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3958<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3959<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3960
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3961<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3962<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3963 from which to load. The pointer must point to
3964 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3965 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3966 number or order of execution of this <tt>load</tt> with other
3967 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3968 instructions. </p>
3969
3970<p>The optional constant "align" argument specifies the alignment of the
3971 operation (that is, the alignment of the memory address). A value of 0 or an
3972 omitted "align" argument means that the operation has the preferential
3973 alignment for the target. It is the responsibility of the code emitter to
3974 ensure that the alignment information is correct. Overestimating the
3975 alignment results in an undefined behavior. Underestimating the alignment may
3976 produce less efficient code. An alignment of 1 is always safe.</p>
3977
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3978<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3979<p>The location of memory pointed to is loaded. If the value being loaded is of
3980 scalar type then the number of bytes read does not exceed the minimum number
3981 of bytes needed to hold all bits of the type. For example, loading an
3982 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3983 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3984 is undefined if the value was not originally written using a store of the
3985 same type.</p>
3986
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3987<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3988<pre>
3989 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3990 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3991 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3992</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3993
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3994</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3995
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3996<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3997<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3998Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3999
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4000<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4001
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4002<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4003<pre>
4004 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]4005 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4006</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4007
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4008<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4009<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4010
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4011<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4012<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4013 and an address at which to store it. The type of the
4014 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4015 the <a href="#t_firstclass">first class</a> type of the
4016 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4017 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4018 or order of execution of this <tt>store</tt> with other
4019 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4020 instructions.</p>
4021
4022<p>The optional constant "align" argument specifies the alignment of the
4023 operation (that is, the alignment of the memory address). A value of 0 or an
4024 omitted "align" argument means that the operation has the preferential
4025 alignment for the target. It is the responsibility of the code emitter to
4026 ensure that the alignment information is correct. Overestimating the
4027 alignment results in an undefined behavior. Underestimating the alignment may
4028 produce less efficient code. An alignment of 1 is always safe.</p>
4029
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4030<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4031<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4032 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4033 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4034 does not exceed the minimum number of bytes needed to hold all bits of the
4035 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4036 writing a value of a type like <tt>i20</tt> with a size that is not an
4037 integral number of bytes, it is unspecified what happens to the extra bits
4038 that do not belong to the type, but they will typically be overwritten.</p>
4039
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4040<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4041<pre>
4042 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4043 store i32 3, i32* %ptr <i>; yields {void}</i>
4044 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4045</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4046
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4047</div>
4048
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4049<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4050<div class="doc_subsubsection">
4051 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4052</div>
4053
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4054<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4055
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4056<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4057<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4058 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4059 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4060</pre>
4061
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4062<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4063<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4064 subelement of an aggregate data structure. It performs address calculation
4065 only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4066
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4067<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4068<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4069 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4070 elements of the aggregate object are indexed. The interpretation of each
4071 index is dependent on the type being indexed into. The first index always
4072 indexes the pointer value given as the first argument, the second index
4073 indexes a value of the type pointed to (not necessarily the value directly
4074 pointed to, since the first index can be non-zero), etc. The first type
4075 indexed into must be a pointer value, subsequent types can be arrays, vectors
4076 and structs. Note that subsequent types being indexed into can never be
4077 pointers, since that would require loading the pointer before continuing
4078 calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4079
4080<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4081 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4082 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4083 vector, integers of any width are allowed, and they are not required to be
4084 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4085
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4086<p>For example, let's consider a C code fragment and how it gets compiled to
4087 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4088
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4089<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4090<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4091struct RT {
4092 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4093 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4094 char C;
4095};
4096struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4097 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4098 double Y;
4099 struct RT Z;
4100};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4101
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4102int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4103 return &amp;s[1].Z.B[5][13];
4104}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4105</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4106</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4107
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4108<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4109
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4110<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4111<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4112%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4113%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4114
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4115define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4116entry:
4117 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4118 ret i32* %reg
4119}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4120</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4121</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4122
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4123<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4124<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4125 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4126 }</tt>' type, a structure. The second index indexes into the third element
4127 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4128 i8 }</tt>' type, another structure. The third index indexes into the second
4129 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4130 array. The two dimensions of the array are subscripted into, yielding an
4131 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4132 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4133
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4134<p>Note that it is perfectly legal to index partially through a structure,
4135 returning a pointer to an inner element. Because of this, the LLVM code for
4136 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4137
4138<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4139 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4140 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4141 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4142 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4143 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4144 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4145 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4146 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4147</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4148
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4149<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4150 <tt>getelementptr</tt> is undefined if the base pointer is not an
4151 <i>in bounds</i> address of an allocated object, or if any of the addresses
Dan Gohman2de532c2009-08-20 17:08:17 +0000[diff] [blame]4152 that would be formed by successive addition of the offsets implied by the
4153 indices to the base address with infinitely precise arithmetic are not an
4154 <i>in bounds</i> address of that allocated object.
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4155 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohman2de532c2009-08-20 17:08:17 +0000[diff] [blame]4156 that point into the object, plus the address one byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4157
4158<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4159 the base address with silently-wrapping two's complement arithmetic, and
4160 the result value of the <tt>getelementptr</tt> may be outside the object
4161 pointed to by the base pointer. The result value may not necessarily be
4162 used to access memory though, even if it happens to point into allocated
4163 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4164 section for more information.</p>
4165
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4166<p>The getelementptr instruction is often confusing. For some more insight into
4167 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4168
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4169<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4170<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4171 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4172 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4173 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4174 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4175 <i>; yields i8*:eptr</i>
4176 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4177 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4178 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4179</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4180
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4181</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4182
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4183<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4184<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4185</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4186
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4187<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4188
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4189<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4190 which all take a single operand and a type. They perform various bit
4191 conversions on the operand.</p>
4192
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4193</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4194
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4195<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4196<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4197 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4198</div>
4199<div class="doc_text">
4200
4201<h5>Syntax:</h5>
4202<pre>
4203 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4204</pre>
4205
4206<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4207<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4208 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4209
4210<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4211<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4212 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4213 size and type of the result, which must be
4214 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4215 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4216 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4217
4218<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4219<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4220 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4221 source size must be larger than the destination size, <tt>trunc</tt> cannot
4222 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4223
4224<h5>Example:</h5>
4225<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4226 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4227 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4228 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4229</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4230
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4231</div>
4232
4233<!-- _______________________________________________________________________ -->
4234<div class="doc_subsubsection">
4235 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4236</div>
4237<div class="doc_text">
4238
4239<h5>Syntax:</h5>
4240<pre>
4241 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4242</pre>
4243
4244<h5>Overview:</h5>
4245<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4246 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4247
4248
4249<h5>Arguments:</h5>
4250<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4251 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4252 also be of <a href="#t_integer">integer</a> type. The bit size of the
4253 <tt>value</tt> must be smaller than the bit size of the destination type,
4254 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4255
4256<h5>Semantics:</h5>
4257<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4258 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4259
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4260<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4261
4262<h5>Example:</h5>
4263<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4264 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4265 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4266</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4267
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4268</div>
4269
4270<!-- _______________________________________________________________________ -->
4271<div class="doc_subsubsection">
4272 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4273</div>
4274<div class="doc_text">
4275
4276<h5>Syntax:</h5>
4277<pre>
4278 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4279</pre>
4280
4281<h5>Overview:</h5>
4282<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4283
4284<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4285<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4286 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4287 also be of <a href="#t_integer">integer</a> type. The bit size of the
4288 <tt>value</tt> must be smaller than the bit size of the destination type,
4289 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4290
4291<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4292<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4293 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4294 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4295
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4296<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4297
4298<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4299<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4300 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4301 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4302</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4303
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4304</div>
4305
4306<!-- _______________________________________________________________________ -->
4307<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4308 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4309</div>
4310
4311<div class="doc_text">
4312
4313<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4314<pre>
4315 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4316</pre>
4317
4318<h5>Overview:</h5>
4319<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4320 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4321
4322<h5>Arguments:</h5>
4323<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4324 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4325 to cast it to. The size of <tt>value</tt> must be larger than the size of
4326 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4327 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4328
4329<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4330<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4331 <a href="#t_floating">floating point</a> type to a smaller
4332 <a href="#t_floating">floating point</a> type. If the value cannot fit
4333 within the destination type, <tt>ty2</tt>, then the results are
4334 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4335
4336<h5>Example:</h5>
4337<pre>
4338 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4339 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4340</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4341
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4342</div>
4343
4344<!-- _______________________________________________________________________ -->
4345<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4346 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4347</div>
4348<div class="doc_text">
4349
4350<h5>Syntax:</h5>
4351<pre>
4352 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4353</pre>
4354
4355<h5>Overview:</h5>
4356<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4357 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4358
4359<h5>Arguments:</h5>
4360<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4361 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4362 a <a href="#t_floating">floating point</a> type to cast it to. The source
4363 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4364
4365<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4366<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4367 <a href="#t_floating">floating point</a> type to a larger
4368 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4369 used to make a <i>no-op cast</i> because it always changes bits. Use
4370 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4371
4372<h5>Example:</h5>
4373<pre>
4374 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4375 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4376</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4377
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4378</div>
4379
4380<!-- _______________________________________________________________________ -->
4381<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4382 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4383</div>
4384<div class="doc_text">
4385
4386<h5>Syntax:</h5>
4387<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4388 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4389</pre>
4390
4391<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4392<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4393 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4394
4395<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4396<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4397 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4398 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4399 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4400 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4401
4402<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4403<p>The '<tt>fptoui</tt>' instruction converts its
4404 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4405 towards zero) unsigned integer value. If the value cannot fit
4406 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4407
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4408<h5>Example:</h5>
4409<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4410 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4411 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4412 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4413</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4414
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4415</div>
4416
4417<!-- _______________________________________________________________________ -->
4418<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4419 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4420</div>
4421<div class="doc_text">
4422
4423<h5>Syntax:</h5>
4424<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4425 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4426</pre>
4427
4428<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4429<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4430 <a href="#t_floating">floating point</a> <tt>value</tt> to
4431 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4432
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4433<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4434<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4435 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4436 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4437 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4438 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4439
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4440<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4441<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4442 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4443 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4444 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4445
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4446<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4447<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4448 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4449 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4450 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4451</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4452
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4453</div>
4454
4455<!-- _______________________________________________________________________ -->
4456<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4457 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4458</div>
4459<div class="doc_text">
4460
4461<h5>Syntax:</h5>
4462<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4463 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4464</pre>
4465
4466<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4467<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4468 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4469
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4470<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4471<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4472 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4473 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4474 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4475 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4476
4477<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4478<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4479 integer quantity and converts it to the corresponding floating point
4480 value. If the value cannot fit in the floating point value, the results are
4481 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4482
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4483<h5>Example:</h5>
4484<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4485 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4486 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4487</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4488
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4489</div>
4490
4491<!-- _______________________________________________________________________ -->
4492<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4493 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4494</div>
4495<div class="doc_text">
4496
4497<h5>Syntax:</h5>
4498<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4499 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4500</pre>
4501
4502<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4503<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4504 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4505
4506<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4507<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4508 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4509 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4510 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4511 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4512
4513<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4514<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4515 quantity and converts it to the corresponding floating point value. If the
4516 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4517
4518<h5>Example:</h5>
4519<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4520 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4521 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4522</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4523
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4524</div>
4525
4526<!-- _______________________________________________________________________ -->
4527<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4528 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4529</div>
4530<div class="doc_text">
4531
4532<h5>Syntax:</h5>
4533<pre>
4534 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4535</pre>
4536
4537<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4538<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4539 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4540
4541<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4542<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4543 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4544 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4545
4546<h5>Semantics:</h5>
4547<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4548 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4549 truncating or zero extending that value to the size of the integer type. If
4550 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4551 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4552 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4553 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4554
4555<h5>Example:</h5>
4556<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4557 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4558 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4559</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4560
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4561</div>
4562
4563<!-- _______________________________________________________________________ -->
4564<div class="doc_subsubsection">
4565 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4566</div>
4567<div class="doc_text">
4568
4569<h5>Syntax:</h5>
4570<pre>
4571 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4572</pre>
4573
4574<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4575<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4576 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4577
4578<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4579<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4580 value to cast, and a type to cast it to, which must be a
4581 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4582
4583<h5>Semantics:</h5>
4584<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4585 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4586 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4587 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4588 than the size of a pointer then a zero extension is done. If they are the
4589 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4590
4591<h5>Example:</h5>
4592<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4593 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4594 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4595 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4596</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4597
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4598</div>
4599
4600<!-- _______________________________________________________________________ -->
4601<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4602 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4603</div>
4604<div class="doc_text">
4605
4606<h5>Syntax:</h5>
4607<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4608 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4609</pre>
4610
4611<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4612<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4613 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4614
4615<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4616<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4617 non-aggregate first class value, and a type to cast it to, which must also be
4618 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4619 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4620 identical. If the source type is a pointer, the destination type must also be
4621 a pointer. This instruction supports bitwise conversion of vectors to
4622 integers and to vectors of other types (as long as they have the same
4623 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4624
4625<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4626<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4627 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4628 this conversion. The conversion is done as if the <tt>value</tt> had been
4629 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4630 be converted to other pointer types with this instruction. To convert
4631 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4632 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4633
4634<h5>Example:</h5>
4635<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4636 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4637 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4638 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4639</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4640
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4641</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4642
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4643<!-- ======================================================================= -->
4644<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4645
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4646<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4647
4648<p>The instructions in this category are the "miscellaneous" instructions, which
4649 defy better classification.</p>
4650
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4651</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4652
4653<!-- _______________________________________________________________________ -->
4654<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4655</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4656
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4657<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4658
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4659<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4660<pre>
4661 &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4662</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4663
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4664<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4665<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4666 boolean values based on comparison of its two integer, integer vector, or
4667 pointer operands.</p>
4668
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4669<h5>Arguments:</h5>
4670<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4671 the condition code indicating the kind of comparison to perform. It is not a
4672 value, just a keyword. The possible condition code are:</p>
4673
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4674<ol>
4675 <li><tt>eq</tt>: equal</li>
4676 <li><tt>ne</tt>: not equal </li>
4677 <li><tt>ugt</tt>: unsigned greater than</li>
4678 <li><tt>uge</tt>: unsigned greater or equal</li>
4679 <li><tt>ult</tt>: unsigned less than</li>
4680 <li><tt>ule</tt>: unsigned less or equal</li>
4681 <li><tt>sgt</tt>: signed greater than</li>
4682 <li><tt>sge</tt>: signed greater or equal</li>
4683 <li><tt>slt</tt>: signed less than</li>
4684 <li><tt>sle</tt>: signed less or equal</li>
4685</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4686
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]4687<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4688 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4689 typed. They must also be identical types.</p>
4690
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4691<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4692<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4693 condition code given as <tt>cond</tt>. The comparison performed always yields
4694 either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
4695 result, as follows:</p>
4696
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4697<ol>
4698 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4699 <tt>false</tt> otherwise. No sign interpretation is necessary or
4700 performed.</li>
4701
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4702 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4703 <tt>false</tt> otherwise. No sign interpretation is necessary or
4704 performed.</li>
4705
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4706 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4707 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4708
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4709 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4710 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4711 to <tt>op2</tt>.</li>
4712
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4713 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4714 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4715
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4716 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4717 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4718
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4719 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4720 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4721
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4722 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4723 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4724 to <tt>op2</tt>.</li>
4725
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4726 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4727 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4728
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4729 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4730 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4731</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4732
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4733<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4734 values are compared as if they were integers.</p>
4735
4736<p>If the operands are integer vectors, then they are compared element by
4737 element. The result is an <tt>i1</tt> vector with the same number of elements
4738 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4739
4740<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4741<pre>
4742 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4743 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4744 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4745 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4746 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4747 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4748</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4749
4750<p>Note that the code generator does not yet support vector types with
4751 the <tt>icmp</tt> instruction.</p>
4752
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4753</div>
4754
4755<!-- _______________________________________________________________________ -->
4756<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4757</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4758
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4759<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4760
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4761<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4762<pre>
4763 &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4764</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4765
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4766<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4767<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4768 values based on comparison of its operands.</p>
4769
4770<p>If the operands are floating point scalars, then the result type is a boolean
4771(<a href="#t_primitive"><tt>i1</tt></a>).</p>
4772
4773<p>If the operands are floating point vectors, then the result type is a vector
4774 of boolean with the same number of elements as the operands being
4775 compared.</p>
4776
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4777<h5>Arguments:</h5>
4778<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4779 the condition code indicating the kind of comparison to perform. It is not a
4780 value, just a keyword. The possible condition code are:</p>
4781
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4782<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4783 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4784 <li><tt>oeq</tt>: ordered and equal</li>
4785 <li><tt>ogt</tt>: ordered and greater than </li>
4786 <li><tt>oge</tt>: ordered and greater than or equal</li>
4787 <li><tt>olt</tt>: ordered and less than </li>
4788 <li><tt>ole</tt>: ordered and less than or equal</li>
4789 <li><tt>one</tt>: ordered and not equal</li>
4790 <li><tt>ord</tt>: ordered (no nans)</li>
4791 <li><tt>ueq</tt>: unordered or equal</li>
4792 <li><tt>ugt</tt>: unordered or greater than </li>
4793 <li><tt>uge</tt>: unordered or greater than or equal</li>
4794 <li><tt>ult</tt>: unordered or less than </li>
4795 <li><tt>ule</tt>: unordered or less than or equal</li>
4796 <li><tt>une</tt>: unordered or not equal</li>
4797 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4798 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4799</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4800
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4801<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4802 <i>unordered</i> means that either operand may be a QNAN.</p>
4803
4804<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4805 a <a href="#t_floating">floating point</a> type or
4806 a <a href="#t_vector">vector</a> of floating point type. They must have
4807 identical types.</p>
4808
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4809<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4810<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4811 according to the condition code given as <tt>cond</tt>. If the operands are
4812 vectors, then the vectors are compared element by element. Each comparison
4813 performed always yields an <a href="#t_primitive">i1</a> result, as
4814 follows:</p>
4815
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4816<ol>
4817 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4818
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4819 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4820 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4821
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4822 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4823 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4824
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4825 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4826 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4827
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4828 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4829 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4830
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4831 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4832 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4833
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4834 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4835 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4836
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4837 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4838
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4839 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4840 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4841
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4842 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4843 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4844
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4845 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4846 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4847
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4848 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4849 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4850
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4851 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4852 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4853
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4854 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4855 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4856
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4857 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4858
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4859 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4860</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4861
4862<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4863<pre>
4864 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]4865 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4866 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4867 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4868</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4869
4870<p>Note that the code generator does not yet support vector types with
4871 the <tt>fcmp</tt> instruction.</p>
4872
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4873</div>
4874
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4875<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]4876<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4877 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4878</div>
4879
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4880<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4881
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4882<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4883<pre>
4884 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4885</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4886
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4887<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4888<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4889 SSA graph representing the function.</p>
4890
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4891<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4892<p>The type of the incoming values is specified with the first type field. After
4893 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4894 one pair for each predecessor basic block of the current block. Only values
4895 of <a href="#t_firstclass">first class</a> type may be used as the value
4896 arguments to the PHI node. Only labels may be used as the label
4897 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4898
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4899<p>There must be no non-phi instructions between the start of a basic block and
4900 the PHI instructions: i.e. PHI instructions must be first in a basic
4901 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4902
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4903<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4904 occur on the edge from the corresponding predecessor block to the current
4905 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4906 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]4907
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4908<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4909<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4910 specified by the pair corresponding to the predecessor basic block that
4911 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4912
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4913<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4914<pre>
4915Loop: ; Infinite loop that counts from 0 on up...
4916 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4917 %nextindvar = add i32 %indvar, 1
4918 br label %Loop
4919</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4920
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4921</div>
4922
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4923<!-- _______________________________________________________________________ -->
4924<div class="doc_subsubsection">
4925 <a name="i_select">'<tt>select</tt>' Instruction</a>
4926</div>
4927
4928<div class="doc_text">
4929
4930<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4931<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]4932 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
4933
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4934 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4935</pre>
4936
4937<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4938<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4939 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4940
4941
4942<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4943<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4944 values indicating the condition, and two values of the
4945 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4946 vectors and the condition is a scalar, then entire vectors are selected, not
4947 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4948
4949<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4950<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4951 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4952
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4953<p>If the condition is a vector of i1, then the value arguments must be vectors
4954 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4955
4956<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4957<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4958 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4959</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4960
4961<p>Note that the code generator does not yet support conditions
4962 with vector type.</p>
4963
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4964</div>
4965
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]4966<!-- _______________________________________________________________________ -->
4967<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4968 <a name="i_call">'<tt>call</tt>' Instruction</a>
4969</div>
4970
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4971<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4972
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4973<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4974<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]4975 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4976</pre>
4977
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4978<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4979<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4980
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4981<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4982<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4983
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4984<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4985 <li>The optional "tail" marker indicates whether the callee function accesses
4986 any allocas or varargs in the caller. If the "tail" marker is present,
4987 the function call is eligible for tail call optimization. Note that calls
4988 may be marked "tail" even if they do not occur before
4989 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]4990
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4991 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4992 convention</a> the call should use. If none is specified, the call
4993 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]4994
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4995 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4996 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4997 '<tt>inreg</tt>' attributes are valid here.</li>
4998
4999 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5000 type of the return value. Functions that return no value are marked
5001 <tt><a href="#t_void">void</a></tt>.</li>
5002
5003 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5004 being invoked. The argument types must match the types implied by this
5005 signature. This type can be omitted if the function is not varargs and if
5006 the function type does not return a pointer to a function.</li>
5007
5008 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5009 be invoked. In most cases, this is a direct function invocation, but
5010 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5011 to function value.</li>
5012
5013 <li>'<tt>function args</tt>': argument list whose types match the function
5014 signature argument types. All arguments must be of
5015 <a href="#t_firstclass">first class</a> type. If the function signature
5016 indicates the function accepts a variable number of arguments, the extra
5017 arguments can be specified.</li>
5018
5019 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5020 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5021 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5022</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5023
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5024<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5025<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5026 a specified function, with its incoming arguments bound to the specified
5027 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5028 function, control flow continues with the instruction after the function
5029 call, and the return value of the function is bound to the result
5030 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5031
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5032<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5033<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5034 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5035 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5036 %X = tail call i32 @foo() <i>; yields i32</i>
5037 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5038 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5039
5040 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5041 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5042 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5043 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5044 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5045 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5046</pre>
5047
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5048<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame^]5049standard C99 library as being the C99 library functions, and may perform
5050optimizations or generate code for them under that assumption. This is
5051something we'd like to change in the future to provide better support for
5052freestanding environments and non-C-based langauges.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5053
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5054</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5055
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5056<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5057<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5058 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5059</div>
5060
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5061<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5062
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5063<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5064<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5065 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5066</pre>
5067
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5068<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5069<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5070 the "variable argument" area of a function call. It is used to implement the
5071 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5072
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5073<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5074<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5075 argument. It returns a value of the specified argument type and increments
5076 the <tt>va_list</tt> to point to the next argument. The actual type
5077 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5078
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5079<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5080<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5081 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5082 to the next argument. For more information, see the variable argument
5083 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5084
5085<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5086 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5087 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5088
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5089<p><tt>va_arg</tt> is an LLVM instruction instead of
5090 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5091 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5092
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5093<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5094<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5095
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5096<p>Note that the code generator does not yet fully support va_arg on many
5097 targets. Also, it does not currently support va_arg with aggregate types on
5098 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5099
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5100</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5101
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5102<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5103<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5104<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5105
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5106<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5107
5108<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5109 well known names and semantics and are required to follow certain
5110 restrictions. Overall, these intrinsics represent an extension mechanism for
5111 the LLVM language that does not require changing all of the transformations
5112 in LLVM when adding to the language (or the bitcode reader/writer, the
5113 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5114
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5115<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5116 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5117 begin with this prefix. Intrinsic functions must always be external
5118 functions: you cannot define the body of intrinsic functions. Intrinsic
5119 functions may only be used in call or invoke instructions: it is illegal to
5120 take the address of an intrinsic function. Additionally, because intrinsic
5121 functions are part of the LLVM language, it is required if any are added that
5122 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5123
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5124<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5125 family of functions that perform the same operation but on different data
5126 types. Because LLVM can represent over 8 million different integer types,
5127 overloading is used commonly to allow an intrinsic function to operate on any
5128 integer type. One or more of the argument types or the result type can be
5129 overloaded to accept any integer type. Argument types may also be defined as
5130 exactly matching a previous argument's type or the result type. This allows
5131 an intrinsic function which accepts multiple arguments, but needs all of them
5132 to be of the same type, to only be overloaded with respect to a single
5133 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5134
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5135<p>Overloaded intrinsics will have the names of its overloaded argument types
5136 encoded into its function name, each preceded by a period. Only those types
5137 which are overloaded result in a name suffix. Arguments whose type is matched
5138 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5139 can take an integer of any width and returns an integer of exactly the same
5140 integer width. This leads to a family of functions such as
5141 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5142 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5143 suffix is required. Because the argument's type is matched against the return
5144 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5145
5146<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5147 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5148
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5149</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5150
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5151<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5152<div class="doc_subsection">
5153 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5154</div>
5155
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5156<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5157
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5158<p>Variable argument support is defined in LLVM with
5159 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5160 intrinsic functions. These functions are related to the similarly named
5161 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5162
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5163<p>All of these functions operate on arguments that use a target-specific value
5164 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5165 not define what this type is, so all transformations should be prepared to
5166 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5167
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5168<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5169 instruction and the variable argument handling intrinsic functions are
5170 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5171
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5172<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5173<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5174define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5175 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5176 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5177 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5178 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5179
5180 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5181 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5182
5183 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5184 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5185 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5186 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5187 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5188
5189 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5190 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5191 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5192}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5193
5194declare void @llvm.va_start(i8*)
5195declare void @llvm.va_copy(i8*, i8*)
5196declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5197</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5198</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5199
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5200</div>
5201
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5202<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5203<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5204 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5205</div>
5206
5207
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5208<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5209
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5210<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5211<pre>
5212 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5213</pre>
5214
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5215<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5216<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5217 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5218
5219<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5220<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5221
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5222<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5223<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5224 macro available in C. In a target-dependent way, it initializes
5225 the <tt>va_list</tt> element to which the argument points, so that the next
5226 call to <tt>va_arg</tt> will produce the first variable argument passed to
5227 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5228 need to know the last argument of the function as the compiler can figure
5229 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5230
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5231</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5232
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5233<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5234<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5235 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5236</div>
5237
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5238<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5239
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5240<h5>Syntax:</h5>
5241<pre>
5242 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5243</pre>
5244
5245<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5246<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5247 which has been initialized previously
5248 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5249 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5250
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5251<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5252<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5253
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5254<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5255<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5256 macro available in C. In a target-dependent way, it destroys
5257 the <tt>va_list</tt> element to which the argument points. Calls
5258 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5259 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5260 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5261
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5262</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5263
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5264<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5265<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5266 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5267</div>
5268
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5269<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5270
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5271<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5272<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5273 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5274</pre>
5275
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5276<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5277<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5278 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5279
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5280<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5281<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5282 The second argument is a pointer to a <tt>va_list</tt> element to copy
5283 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5284
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5285<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5286<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5287 macro available in C. In a target-dependent way, it copies the
5288 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5289 element. This intrinsic is necessary because
5290 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5291 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5292
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5293</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5294
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5295<!-- ======================================================================= -->
5296<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5297 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5298</div>
5299
5300<div class="doc_text">
5301
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5302<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5303Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5304intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5305roots on the stack</a>, as well as garbage collector implementations that
5306require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5307barriers. Front-ends for type-safe garbage collected languages should generate
5308these intrinsics to make use of the LLVM garbage collectors. For more details,
5309see <a href="GarbageCollection.html">Accurate Garbage Collection with
5310LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5311
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5312<p>The garbage collection intrinsics only operate on objects in the generic
5313 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5314
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5315</div>
5316
5317<!-- _______________________________________________________________________ -->
5318<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5319 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5320</div>
5321
5322<div class="doc_text">
5323
5324<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5325<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5326 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5327</pre>
5328
5329<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5330<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5331 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5332
5333<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5334<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5335 root pointer. The second pointer (which must be either a constant or a
5336 global value address) contains the meta-data to be associated with the
5337 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5338
5339<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5340<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5341 location. At compile-time, the code generator generates information to allow
5342 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5343 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5344 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5345
5346</div>
5347
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5348<!-- _______________________________________________________________________ -->
5349<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5350 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5351</div>
5352
5353<div class="doc_text">
5354
5355<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5356<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5357 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5358</pre>
5359
5360<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5361<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5362 locations, allowing garbage collector implementations that require read
5363 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5364
5365<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5366<p>The second argument is the address to read from, which should be an address
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5367 allocated from the garbage collector. The first object is a pointer to the
5368 start of the referenced object, if needed by the language runtime (otherwise
5369 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5370
5371<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5372<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5373 instruction, but may be replaced with substantially more complex code by the
5374 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5375 may only be used in a function which <a href="#gc">specifies a GC
5376 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5377
5378</div>
5379
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5380<!-- _______________________________________________________________________ -->
5381<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5382 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5383</div>
5384
5385<div class="doc_text">
5386
5387<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5388<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5389 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5390</pre>
5391
5392<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5393<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5394 locations, allowing garbage collector implementations that require write
5395 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5396
5397<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5398<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5399 object to store it to, and the third is the address of the field of Obj to
5400 store to. If the runtime does not require a pointer to the object, Obj may
5401 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5402
5403<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5404<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5405 instruction, but may be replaced with substantially more complex code by the
5406 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5407 may only be used in a function which <a href="#gc">specifies a GC
5408 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5409
5410</div>
5411
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5412<!-- ======================================================================= -->
5413<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5414 <a name="int_codegen">Code Generator Intrinsics</a>
5415</div>
5416
5417<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5418
5419<p>These intrinsics are provided by LLVM to expose special features that may
5420 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5421
5422</div>
5423
5424<!-- _______________________________________________________________________ -->
5425<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5426 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5427</div>
5428
5429<div class="doc_text">
5430
5431<h5>Syntax:</h5>
5432<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5433 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5434</pre>
5435
5436<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5437<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5438 target-specific value indicating the return address of the current function
5439 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5440
5441<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5442<p>The argument to this intrinsic indicates which function to return the address
5443 for. Zero indicates the calling function, one indicates its caller, etc.
5444 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5445
5446<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5447<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5448 indicating the return address of the specified call frame, or zero if it
5449 cannot be identified. The value returned by this intrinsic is likely to be
5450 incorrect or 0 for arguments other than zero, so it should only be used for
5451 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5452
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5453<p>Note that calling this intrinsic does not prevent function inlining or other
5454 aggressive transformations, so the value returned may not be that of the
5455 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5456
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5457</div>
5458
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5459<!-- _______________________________________________________________________ -->
5460<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5461 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5462</div>
5463
5464<div class="doc_text">
5465
5466<h5>Syntax:</h5>
5467<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5468 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5469</pre>
5470
5471<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5472<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5473 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5474
5475<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5476<p>The argument to this intrinsic indicates which function to return the frame
5477 pointer for. Zero indicates the calling function, one indicates its caller,
5478 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5479
5480<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5481<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5482 indicating the frame address of the specified call frame, or zero if it
5483 cannot be identified. The value returned by this intrinsic is likely to be
5484 incorrect or 0 for arguments other than zero, so it should only be used for
5485 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5486
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5487<p>Note that calling this intrinsic does not prevent function inlining or other
5488 aggressive transformations, so the value returned may not be that of the
5489 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5490
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5491</div>
5492
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5493<!-- _______________________________________________________________________ -->
5494<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5495 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5496</div>
5497
5498<div class="doc_text">
5499
5500<h5>Syntax:</h5>
5501<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5502 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5503</pre>
5504
5505<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5506<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5507 of the function stack, for use
5508 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5509 useful for implementing language features like scoped automatic variable
5510 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5511
5512<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5513<p>This intrinsic returns a opaque pointer value that can be passed
5514 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5515 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5516 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5517 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5518 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5519 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5520
5521</div>
5522
5523<!-- _______________________________________________________________________ -->
5524<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5525 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5526</div>
5527
5528<div class="doc_text">
5529
5530<h5>Syntax:</h5>
5531<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5532 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5533</pre>
5534
5535<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5536<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5537 the function stack to the state it was in when the
5538 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5539 executed. This is useful for implementing language features like scoped
5540 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5541
5542<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5543<p>See the description
5544 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5545
5546</div>
5547
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5548<!-- _______________________________________________________________________ -->
5549<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5550 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5551</div>
5552
5553<div class="doc_text">
5554
5555<h5>Syntax:</h5>
5556<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5557 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5558</pre>
5559
5560<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5561<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5562 insert a prefetch instruction if supported; otherwise, it is a noop.
5563 Prefetches have no effect on the behavior of the program but can change its
5564 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5565
5566<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5567<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5568 specifier determining if the fetch should be for a read (0) or write (1),
5569 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5570 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5571 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5572
5573<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5574<p>This intrinsic does not modify the behavior of the program. In particular,
5575 prefetches cannot trap and do not produce a value. On targets that support
5576 this intrinsic, the prefetch can provide hints to the processor cache for
5577 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5578
5579</div>
5580
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5581<!-- _______________________________________________________________________ -->
5582<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5583 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5584</div>
5585
5586<div class="doc_text">
5587
5588<h5>Syntax:</h5>
5589<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5590 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5591</pre>
5592
5593<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5594<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5595 Counter (PC) in a region of code to simulators and other tools. The method
5596 is target specific, but it is expected that the marker will use exported
5597 symbols to transmit the PC of the marker. The marker makes no guarantees
5598 that it will remain with any specific instruction after optimizations. It is
5599 possible that the presence of a marker will inhibit optimizations. The
5600 intended use is to be inserted after optimizations to allow correlations of
5601 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5602
5603<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5604<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5605
5606<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5607<p>This intrinsic does not modify the behavior of the program. Backends that do
5608 not support this intrinisic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5609
5610</div>
5611
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5612<!-- _______________________________________________________________________ -->
5613<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5614 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5615</div>
5616
5617<div class="doc_text">
5618
5619<h5>Syntax:</h5>
5620<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5621 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5622</pre>
5623
5624<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5625<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5626 counter register (or similar low latency, high accuracy clocks) on those
5627 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5628 should map to RPCC. As the backing counters overflow quickly (on the order
5629 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5630
5631<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5632<p>When directly supported, reading the cycle counter should not modify any
5633 memory. Implementations are allowed to either return a application specific
5634 value or a system wide value. On backends without support, this is lowered
5635 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5636
5637</div>
5638
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5639<!-- ======================================================================= -->
5640<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5641 <a name="int_libc">Standard C Library Intrinsics</a>
5642</div>
5643
5644<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5645
5646<p>LLVM provides intrinsics for a few important standard C library functions.
5647 These intrinsics allow source-language front-ends to pass information about
5648 the alignment of the pointer arguments to the code generator, providing
5649 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5650
5651</div>
5652
5653<!-- _______________________________________________________________________ -->
5654<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5655 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5656</div>
5657
5658<div class="doc_text">
5659
5660<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5661<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5662 integer bit width. Not all targets support all bit widths however.</p>
5663
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5664<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5665 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5666 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5667 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5668 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5669 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5670 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5671 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5672 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5673</pre>
5674
5675<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5676<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5677 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5678
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5679<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5680 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5681
5682<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5683<p>The first argument is a pointer to the destination, the second is a pointer
5684 to the source. The third argument is an integer argument specifying the
5685 number of bytes to copy, and the fourth argument is the alignment of the
5686 source and destination locations.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5687
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5688<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5689 then the caller guarantees that both the source and destination pointers are
5690 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5691
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5692<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5693<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5694 source location to the destination location, which are not allowed to
5695 overlap. It copies "len" bytes of memory over. If the argument is known to
5696 be aligned to some boundary, this can be specified as the fourth argument,
5697 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5698
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5699</div>
5700
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5701<!-- _______________________________________________________________________ -->
5702<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5703 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5704</div>
5705
5706<div class="doc_text">
5707
5708<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5709<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5710 width. Not all targets support all bit widths however.</p>
5711
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5712<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5713 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5714 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5715 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5716 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5717 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5718 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5719 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5720 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5721</pre>
5722
5723<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5724<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5725 source location to the destination location. It is similar to the
5726 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5727 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5728
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5729<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5730 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5731
5732<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5733<p>The first argument is a pointer to the destination, the second is a pointer
5734 to the source. The third argument is an integer argument specifying the
5735 number of bytes to copy, and the fourth argument is the alignment of the
5736 source and destination locations.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5737
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5738<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5739 then the caller guarantees that the source and destination pointers are
5740 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5741
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5742<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5743<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5744 source location to the destination location, which may overlap. It copies
5745 "len" bytes of memory over. If the argument is known to be aligned to some
5746 boundary, this can be specified as the fourth argument, otherwise it should
5747 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5748
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5749</div>
5750
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5751<!-- _______________________________________________________________________ -->
5752<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5753 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5754</div>
5755
5756<div class="doc_text">
5757
5758<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5759<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5760 width. Not all targets support all bit widths however.</p>
5761
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5762<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5763 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5764 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5765 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5766 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5767 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5768 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5769 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5770 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5771</pre>
5772
5773<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5774<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5775 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5776
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5777<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5778 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5779
5780<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5781<p>The first argument is a pointer to the destination to fill, the second is the
5782 byte value to fill it with, the third argument is an integer argument
5783 specifying the number of bytes to fill, and the fourth argument is the known
5784 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5785
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5786<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5787 then the caller guarantees that the destination pointer is aligned to that
5788 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5789
5790<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5791<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5792 at the destination location. If the argument is known to be aligned to some
5793 boundary, this can be specified as the fourth argument, otherwise it should
5794 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5795
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5796</div>
5797
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5798<!-- _______________________________________________________________________ -->
5799<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5800 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5801</div>
5802
5803<div class="doc_text">
5804
5805<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5806<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5807 floating point or vector of floating point type. Not all targets support all
5808 types however.</p>
5809
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5810<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5811 declare float @llvm.sqrt.f32(float %Val)
5812 declare double @llvm.sqrt.f64(double %Val)
5813 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5814 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5815 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5816</pre>
5817
5818<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5819<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5820 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5821 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5822 behavior for negative numbers other than -0.0 (which allows for better
5823 optimization, because there is no need to worry about errno being
5824 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5825
5826<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5827<p>The argument and return value are floating point numbers of the same
5828 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5829
5830<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5831<p>This function returns the sqrt of the specified operand if it is a
5832 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5833
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5834</div>
5835
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5836<!-- _______________________________________________________________________ -->
5837<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5838 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5839</div>
5840
5841<div class="doc_text">
5842
5843<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5844<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5845 floating point or vector of floating point type. Not all targets support all
5846 types however.</p>
5847
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5848<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5849 declare float @llvm.powi.f32(float %Val, i32 %power)
5850 declare double @llvm.powi.f64(double %Val, i32 %power)
5851 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5852 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5853 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5854</pre>
5855
5856<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5857<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5858 specified (positive or negative) power. The order of evaluation of
5859 multiplications is not defined. When a vector of floating point type is
5860 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5861
5862<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5863<p>The second argument is an integer power, and the first is a value to raise to
5864 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5865
5866<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5867<p>This function returns the first value raised to the second power with an
5868 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5869
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5870</div>
5871
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5872<!-- _______________________________________________________________________ -->
5873<div class="doc_subsubsection">
5874 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5875</div>
5876
5877<div class="doc_text">
5878
5879<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5880<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5881 floating point or vector of floating point type. Not all targets support all
5882 types however.</p>
5883
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5884<pre>
5885 declare float @llvm.sin.f32(float %Val)
5886 declare double @llvm.sin.f64(double %Val)
5887 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5888 declare fp128 @llvm.sin.f128(fp128 %Val)
5889 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5890</pre>
5891
5892<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5893<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5894
5895<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5896<p>The argument and return value are floating point numbers of the same
5897 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5898
5899<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5900<p>This function returns the sine of the specified operand, returning the same
5901 values as the libm <tt>sin</tt> functions would, and handles error conditions
5902 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5903
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5904</div>
5905
5906<!-- _______________________________________________________________________ -->
5907<div class="doc_subsubsection">
5908 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5909</div>
5910
5911<div class="doc_text">
5912
5913<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5914<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5915 floating point or vector of floating point type. Not all targets support all
5916 types however.</p>
5917
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5918<pre>
5919 declare float @llvm.cos.f32(float %Val)
5920 declare double @llvm.cos.f64(double %Val)
5921 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5922 declare fp128 @llvm.cos.f128(fp128 %Val)
5923 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5924</pre>
5925
5926<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5927<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5928
5929<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5930<p>The argument and return value are floating point numbers of the same
5931 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5932
5933<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5934<p>This function returns the cosine of the specified operand, returning the same
5935 values as the libm <tt>cos</tt> functions would, and handles error conditions
5936 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5937
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5938</div>
5939
5940<!-- _______________________________________________________________________ -->
5941<div class="doc_subsubsection">
5942 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5943</div>
5944
5945<div class="doc_text">
5946
5947<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5948<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5949 floating point or vector of floating point type. Not all targets support all
5950 types however.</p>
5951
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5952<pre>
5953 declare float @llvm.pow.f32(float %Val, float %Power)
5954 declare double @llvm.pow.f64(double %Val, double %Power)
5955 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5956 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5957 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5958</pre>
5959
5960<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5961<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5962 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5963
5964<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5965<p>The second argument is a floating point power, and the first is a value to
5966 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5967
5968<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5969<p>This function returns the first value raised to the second power, returning
5970 the same values as the libm <tt>pow</tt> functions would, and handles error
5971 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5972
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5973</div>
5974
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5975<!-- ======================================================================= -->
5976<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5977 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5978</div>
5979
5980<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5981
5982<p>LLVM provides intrinsics for a few important bit manipulation operations.
5983 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5984
5985</div>
5986
5987<!-- _______________________________________________________________________ -->
5988<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5989 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5990</div>
5991
5992<div class="doc_text">
5993
5994<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5995<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5996 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5997
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5998<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5999 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6000 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6001 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6002</pre>
6003
6004<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6005<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6006 values with an even number of bytes (positive multiple of 16 bits). These
6007 are useful for performing operations on data that is not in the target's
6008 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6009
6010<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6011<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6012 and low byte of the input i16 swapped. Similarly,
6013 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6014 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6015 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6016 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6017 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6018 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6019
6020</div>
6021
6022<!-- _______________________________________________________________________ -->
6023<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6024 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6025</div>
6026
6027<div class="doc_text">
6028
6029<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6030<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6031 width. Not all targets support all bit widths however.</p>
6032
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6033<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6034 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6035 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6036 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6037 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6038 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6039</pre>
6040
6041<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6042<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6043 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6044
6045<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6046<p>The only argument is the value to be counted. The argument may be of any
6047 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6048
6049<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6050<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6051
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6052</div>
6053
6054<!-- _______________________________________________________________________ -->
6055<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6056 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6057</div>
6058
6059<div class="doc_text">
6060
6061<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6062<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6063 integer bit width. Not all targets support all bit widths however.</p>
6064
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6065<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6066 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6067 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6068 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6069 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6070 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6071</pre>
6072
6073<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6074<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6075 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6076
6077<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6078<p>The only argument is the value to be counted. The argument may be of any
6079 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6080
6081<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6082<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6083 zeros in a variable. If the src == 0 then the result is the size in bits of
6084 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6085
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6086</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6087
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6088<!-- _______________________________________________________________________ -->
6089<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6090 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6091</div>
6092
6093<div class="doc_text">
6094
6095<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6096<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6097 integer bit width. Not all targets support all bit widths however.</p>
6098
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6099<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6100 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6101 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6102 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6103 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6104 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6105</pre>
6106
6107<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6108<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6109 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6110
6111<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6112<p>The only argument is the value to be counted. The argument may be of any
6113 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6114
6115<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6116<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6117 zeros in a variable. If the src == 0 then the result is the size in bits of
6118 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6119
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6120</div>
6121
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6122<!-- ======================================================================= -->
6123<div class="doc_subsection">
6124 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6125</div>
6126
6127<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6128
6129<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6130
6131</div>
6132
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6133<!-- _______________________________________________________________________ -->
6134<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6135 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6136</div>
6137
6138<div class="doc_text">
6139
6140<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6141<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6142 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6143
6144<pre>
6145 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6146 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6147 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6148</pre>
6149
6150<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6151<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6152 a signed addition of the two arguments, and indicate whether an overflow
6153 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6154
6155<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6156<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6157 be of integer types of any bit width, but they must have the same bit
6158 width. The second element of the result structure must be of
6159 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6160 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6161
6162<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6163<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6164 a signed addition of the two variables. They return a structure &mdash; the
6165 first element of which is the signed summation, and the second element of
6166 which is a bit specifying if the signed summation resulted in an
6167 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6168
6169<h5>Examples:</h5>
6170<pre>
6171 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6172 %sum = extractvalue {i32, i1} %res, 0
6173 %obit = extractvalue {i32, i1} %res, 1
6174 br i1 %obit, label %overflow, label %normal
6175</pre>
6176
6177</div>
6178
6179<!-- _______________________________________________________________________ -->
6180<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6181 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6182</div>
6183
6184<div class="doc_text">
6185
6186<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6187<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6188 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6189
6190<pre>
6191 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6192 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6193 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6194</pre>
6195
6196<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6197<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6198 an unsigned addition of the two arguments, and indicate whether a carry
6199 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6200
6201<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6202<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6203 be of integer types of any bit width, but they must have the same bit
6204 width. The second element of the result structure must be of
6205 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6206 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6207
6208<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6209<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6210 an unsigned addition of the two arguments. They return a structure &mdash;
6211 the first element of which is the sum, and the second element of which is a
6212 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6213
6214<h5>Examples:</h5>
6215<pre>
6216 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6217 %sum = extractvalue {i32, i1} %res, 0
6218 %obit = extractvalue {i32, i1} %res, 1
6219 br i1 %obit, label %carry, label %normal
6220</pre>
6221
6222</div>
6223
6224<!-- _______________________________________________________________________ -->
6225<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6226 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6227</div>
6228
6229<div class="doc_text">
6230
6231<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6232<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6233 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6234
6235<pre>
6236 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6237 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6238 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6239</pre>
6240
6241<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6242<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6243 a signed subtraction of the two arguments, and indicate whether an overflow
6244 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6245
6246<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6247<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6248 be of integer types of any bit width, but they must have the same bit
6249 width. The second element of the result structure must be of
6250 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6251 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6252
6253<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6254<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6255 a signed subtraction of the two arguments. They return a structure &mdash;
6256 the first element of which is the subtraction, and the second element of
6257 which is a bit specifying if the signed subtraction resulted in an
6258 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6259
6260<h5>Examples:</h5>
6261<pre>
6262 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6263 %sum = extractvalue {i32, i1} %res, 0
6264 %obit = extractvalue {i32, i1} %res, 1
6265 br i1 %obit, label %overflow, label %normal
6266</pre>
6267
6268</div>
6269
6270<!-- _______________________________________________________________________ -->
6271<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6272 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6273</div>
6274
6275<div class="doc_text">
6276
6277<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6278<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6279 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6280
6281<pre>
6282 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6283 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6284 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6285</pre>
6286
6287<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6288<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6289 an unsigned subtraction of the two arguments, and indicate whether an
6290 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6291
6292<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6293<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6294 be of integer types of any bit width, but they must have the same bit
6295 width. The second element of the result structure must be of
6296 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6297 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6298
6299<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6300<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6301 an unsigned subtraction of the two arguments. They return a structure &mdash;
6302 the first element of which is the subtraction, and the second element of
6303 which is a bit specifying if the unsigned subtraction resulted in an
6304 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6305
6306<h5>Examples:</h5>
6307<pre>
6308 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6309 %sum = extractvalue {i32, i1} %res, 0
6310 %obit = extractvalue {i32, i1} %res, 1
6311 br i1 %obit, label %overflow, label %normal
6312</pre>
6313
6314</div>
6315
6316<!-- _______________________________________________________________________ -->
6317<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6318 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6319</div>
6320
6321<div class="doc_text">
6322
6323<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6324<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6325 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6326
6327<pre>
6328 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6329 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6330 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6331</pre>
6332
6333<h5>Overview:</h5>
6334
6335<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6336 a signed multiplication of the two arguments, and indicate whether an
6337 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6338
6339<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6340<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6341 be of integer types of any bit width, but they must have the same bit
6342 width. The second element of the result structure must be of
6343 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6344 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6345
6346<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6347<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6348 a signed multiplication of the two arguments. They return a structure &mdash;
6349 the first element of which is the multiplication, and the second element of
6350 which is a bit specifying if the signed multiplication resulted in an
6351 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6352
6353<h5>Examples:</h5>
6354<pre>
6355 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6356 %sum = extractvalue {i32, i1} %res, 0
6357 %obit = extractvalue {i32, i1} %res, 1
6358 br i1 %obit, label %overflow, label %normal
6359</pre>
6360
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6361</div>
6362
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6363<!-- _______________________________________________________________________ -->
6364<div class="doc_subsubsection">
6365 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6366</div>
6367
6368<div class="doc_text">
6369
6370<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6371<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6372 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6373
6374<pre>
6375 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6376 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6377 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6378</pre>
6379
6380<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6381<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6382 a unsigned multiplication of the two arguments, and indicate whether an
6383 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6384
6385<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6386<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6387 be of integer types of any bit width, but they must have the same bit
6388 width. The second element of the result structure must be of
6389 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6390 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6391
6392<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6393<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6394 an unsigned multiplication of the two arguments. They return a structure
6395 &mdash; the first element of which is the multiplication, and the second
6396 element of which is a bit specifying if the unsigned multiplication resulted
6397 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6398
6399<h5>Examples:</h5>
6400<pre>
6401 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6402 %sum = extractvalue {i32, i1} %res, 0
6403 %obit = extractvalue {i32, i1} %res, 1
6404 br i1 %obit, label %overflow, label %normal
6405</pre>
6406
6407</div>
6408
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6409<!-- ======================================================================= -->
6410<div class="doc_subsection">
6411 <a name="int_debugger">Debugger Intrinsics</a>
6412</div>
6413
6414<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6415
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6416<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6417 prefix), are described in
6418 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6419 Level Debugging</a> document.</p>
6420
6421</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6422
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6423<!-- ======================================================================= -->
6424<div class="doc_subsection">
6425 <a name="int_eh">Exception Handling Intrinsics</a>
6426</div>
6427
6428<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6429
6430<p>The LLVM exception handling intrinsics (which all start with
6431 <tt>llvm.eh.</tt> prefix), are described in
6432 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6433 Handling</a> document.</p>
6434
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6435</div>
6436
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6437<!-- ======================================================================= -->
6438<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6439 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6440</div>
6441
6442<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6443
6444<p>This intrinsic makes it possible to excise one parameter, marked with
6445 the <tt>nest</tt> attribute, from a function. The result is a callable
6446 function pointer lacking the nest parameter - the caller does not need to
6447 provide a value for it. Instead, the value to use is stored in advance in a
6448 "trampoline", a block of memory usually allocated on the stack, which also
6449 contains code to splice the nest value into the argument list. This is used
6450 to implement the GCC nested function address extension.</p>
6451
6452<p>For example, if the function is
6453 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6454 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6455 follows:</p>
6456
6457<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6458<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6459 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6460 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6461 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6462 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6463</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6464</div>
6465
6466<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6467 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6468
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6469</div>
6470
6471<!-- _______________________________________________________________________ -->
6472<div class="doc_subsubsection">
6473 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6474</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6475
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6476<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6477
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6478<h5>Syntax:</h5>
6479<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6480 declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6481</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6482
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6483<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6484<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6485 function pointer suitable for executing it.</p>
6486
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6487<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6488<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6489 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6490 sufficiently aligned block of memory; this memory is written to by the
6491 intrinsic. Note that the size and the alignment are target-specific - LLVM
6492 currently provides no portable way of determining them, so a front-end that
6493 generates this intrinsic needs to have some target-specific knowledge.
6494 The <tt>func</tt> argument must hold a function bitcast to
6495 an <tt>i8*</tt>.</p>
6496
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6497<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6498<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6499 dependent code, turning it into a function. A pointer to this function is
6500 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6501 function pointer type</a> before being called. The new function's signature
6502 is the same as that of <tt>func</tt> with any arguments marked with
6503 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6504 is allowed, and it must be of pointer type. Calling the new function is
6505 equivalent to calling <tt>func</tt> with the same argument list, but
6506 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6507 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6508 by <tt>tramp</tt> is modified, then the effect of any later call to the
6509 returned function pointer is undefined.</p>
6510
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6511</div>
6512
6513<!-- ======================================================================= -->
6514<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6515 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6516</div>
6517
6518<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6519
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6520<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6521 hardware constructs for atomic operations and memory synchronization. This
6522 provides an interface to the hardware, not an interface to the programmer. It
6523 is aimed at a low enough level to allow any programming models or APIs
6524 (Application Programming Interfaces) which need atomic behaviors to map
6525 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6526 hardware provides a "universal IR" for source languages, it also provides a
6527 starting point for developing a "universal" atomic operation and
6528 synchronization IR.</p>
6529
6530<p>These do <em>not</em> form an API such as high-level threading libraries,
6531 software transaction memory systems, atomic primitives, and intrinsic
6532 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6533 application libraries. The hardware interface provided by LLVM should allow
6534 a clean implementation of all of these APIs and parallel programming models.
6535 No one model or paradigm should be selected above others unless the hardware
6536 itself ubiquitously does so.</p>
6537
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6538</div>
6539
6540<!-- _______________________________________________________________________ -->
6541<div class="doc_subsubsection">
6542 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6543</div>
6544<div class="doc_text">
6545<h5>Syntax:</h5>
6546<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6547 declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;, i1 &lt;device&gt; )
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6548</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6549
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6550<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6551<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6552 specific pairs of memory access types.</p>
6553
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6554<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6555<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6556 The first four arguments enables a specific barrier as listed below. The
6557 fith argument specifies that the barrier applies to io or device or uncached
6558 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6559
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6560<ul>
6561 <li><tt>ll</tt>: load-load barrier</li>
6562 <li><tt>ls</tt>: load-store barrier</li>
6563 <li><tt>sl</tt>: store-load barrier</li>
6564 <li><tt>ss</tt>: store-store barrier</li>
6565 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6566</ul>
6567
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6568<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6569<p>This intrinsic causes the system to enforce some ordering constraints upon
6570 the loads and stores of the program. This barrier does not
6571 indicate <em>when</em> any events will occur, it only enforces
6572 an <em>order</em> in which they occur. For any of the specified pairs of load
6573 and store operations (f.ex. load-load, or store-load), all of the first
6574 operations preceding the barrier will complete before any of the second
6575 operations succeeding the barrier begin. Specifically the semantics for each
6576 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6577
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6578<ul>
6579 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6580 after the barrier begins.</li>
6581 <li><tt>ls</tt>: All loads before the barrier must complete before any
6582 store after the barrier begins.</li>
6583 <li><tt>ss</tt>: All stores before the barrier must complete before any
6584 store after the barrier begins.</li>
6585 <li><tt>sl</tt>: All stores before the barrier must complete before any
6586 load after the barrier begins.</li>
6587</ul>
6588
6589<p>These semantics are applied with a logical "and" behavior when more than one
6590 is enabled in a single memory barrier intrinsic.</p>
6591
6592<p>Backends may implement stronger barriers than those requested when they do
6593 not support as fine grained a barrier as requested. Some architectures do
6594 not need all types of barriers and on such architectures, these become
6595 noops.</p>
6596
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6597<h5>Example:</h5>
6598<pre>
6599%ptr = malloc i32
6600 store i32 4, %ptr
6601
6602%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6603 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6604 <i>; guarantee the above finishes</i>
6605 store i32 8, %ptr <i>; before this begins</i>
6606</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6607
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6608</div>
6609
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6610<!-- _______________________________________________________________________ -->
6611<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6612 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6613</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6614
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6615<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6616
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6617<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6618<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6619 any integer bit width and for different address spaces. Not all targets
6620 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6621
6622<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6623 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6624 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6625 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6626 declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6627</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6628
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6629<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6630<p>This loads a value in memory and compares it to a given value. If they are
6631 equal, it stores a new value into the memory.</p>
6632
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6633<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6634<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6635 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6636 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6637 this integer type. While any bit width integer may be used, targets may only
6638 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6639
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6640<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6641<p>This entire intrinsic must be executed atomically. It first loads the value
6642 in memory pointed to by <tt>ptr</tt> and compares it with the
6643 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6644 memory. The loaded value is yielded in all cases. This provides the
6645 equivalent of an atomic compare-and-swap operation within the SSA
6646 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6647
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6648<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6649<pre>
6650%ptr = malloc i32
6651 store i32 4, %ptr
6652
6653%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6654%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6655 <i>; yields {i32}:result1 = 4</i>
6656%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6657%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6658
6659%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6660%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6661 <i>; yields {i32}:result2 = 8</i>
6662%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6663
6664%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6665</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6666
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6667</div>
6668
6669<!-- _______________________________________________________________________ -->
6670<div class="doc_subsubsection">
6671 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6672</div>
6673<div class="doc_text">
6674<h5>Syntax:</h5>
6675
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6676<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6677 integer bit width. Not all targets support all bit widths however.</p>
6678
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6679<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6680 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6681 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6682 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6683 declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6684</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6685
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6686<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6687<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6688 the value from memory. It then stores the value in <tt>val</tt> in the memory
6689 at <tt>ptr</tt>.</p>
6690
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6691<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6692<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6693 the <tt>val</tt> argument and the result must be integers of the same bit
6694 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6695 integer type. The targets may only lower integer representations they
6696 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6697
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6698<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6699<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6700 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6701 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6702
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6703<h5>Examples:</h5>
6704<pre>
6705%ptr = malloc i32
6706 store i32 4, %ptr
6707
6708%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6709%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6710 <i>; yields {i32}:result1 = 4</i>
6711%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6712%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6713
6714%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6715%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6716 <i>; yields {i32}:result2 = 8</i>
6717
6718%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6719%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6720</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6721
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6722</div>
6723
6724<!-- _______________________________________________________________________ -->
6725<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6726 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6727
6728</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6729
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6730<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6731
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6732<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6733<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6734 any integer bit width. Not all targets support all bit widths however.</p>
6735
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6736<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6737 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6738 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6739 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6740 declare i64 @llvm.atomic.load.add.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6741</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6742
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6743<h5>Overview:</h5>
6744<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6745 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6746
6747<h5>Arguments:</h5>
6748<p>The intrinsic takes two arguments, the first a pointer to an integer value
6749 and the second an integer value. The result is also an integer value. These
6750 integer types can have any bit width, but they must all have the same bit
6751 width. The targets may only lower integer representations they support.</p>
6752
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6753<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6754<p>This intrinsic does a series of operations atomically. It first loads the
6755 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6756 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6757
6758<h5>Examples:</h5>
6759<pre>
6760%ptr = malloc i32
6761 store i32 4, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6762%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6763 <i>; yields {i32}:result1 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6764%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6765 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6766%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6767 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6768%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6769</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6770
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6771</div>
6772
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6773<!-- _______________________________________________________________________ -->
6774<div class="doc_subsubsection">
6775 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6776
6777</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6778
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6779<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6780
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6781<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6782<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6783 any integer bit width and for different address spaces. Not all targets
6784 support all bit widths however.</p>
6785
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6786<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6787 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6788 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6789 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6790 declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6791</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6792
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6793<h5>Overview:</h5>
6794<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6795 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6796
6797<h5>Arguments:</h5>
6798<p>The intrinsic takes two arguments, the first a pointer to an integer value
6799 and the second an integer value. The result is also an integer value. These
6800 integer types can have any bit width, but they must all have the same bit
6801 width. The targets may only lower integer representations they support.</p>
6802
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6803<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6804<p>This intrinsic does a series of operations atomically. It first loads the
6805 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6806 result to <tt>ptr</tt>. It yields the original value stored
6807 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6808
6809<h5>Examples:</h5>
6810<pre>
6811%ptr = malloc i32
6812 store i32 8, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6813%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6814 <i>; yields {i32}:result1 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6815%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6816 <i>; yields {i32}:result2 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6817%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6818 <i>; yields {i32}:result3 = 2</i>
6819%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6820</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6821
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6822</div>
6823
6824<!-- _______________________________________________________________________ -->
6825<div class="doc_subsubsection">
6826 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6827 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6828 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6829 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6830</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6831
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6832<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6833
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6834<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6835<p>These are overloaded intrinsics. You can
6836 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6837 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6838 bit width and for different address spaces. Not all targets support all bit
6839 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6840
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6841<pre>
6842 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6843 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6844 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6845 declare i64 @llvm.atomic.load.and.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6846</pre>
6847
6848<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6849 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6850 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6851 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6852 declare i64 @llvm.atomic.load.or.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6853</pre>
6854
6855<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6856 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6857 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6858 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6859 declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6860</pre>
6861
6862<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6863 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6864 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6865 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6866 declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6867</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6868
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6869<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6870<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6871 the value stored in memory at <tt>ptr</tt>. It yields the original value
6872 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6873
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6874<h5>Arguments:</h5>
6875<p>These intrinsics take two arguments, the first a pointer to an integer value
6876 and the second an integer value. The result is also an integer value. These
6877 integer types can have any bit width, but they must all have the same bit
6878 width. The targets may only lower integer representations they support.</p>
6879
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6880<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6881<p>These intrinsics does a series of operations atomically. They first load the
6882 value stored at <tt>ptr</tt>. They then do the bitwise
6883 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6884 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6885
6886<h5>Examples:</h5>
6887<pre>
6888%ptr = malloc i32
6889 store i32 0x0F0F, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6890%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6891 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6892%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6893 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6894%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6895 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6896%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6897 <i>; yields {i32}:result3 = FF</i>
6898%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6899</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6900
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6901</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6902
6903<!-- _______________________________________________________________________ -->
6904<div class="doc_subsubsection">
6905 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6906 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6907 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6908 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6909</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6910
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6911<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6912
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6913<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6914<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6915 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6916 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6917 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6918
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6919<pre>
6920 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6921 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6922 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6923 declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6924</pre>
6925
6926<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6927 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6928 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6929 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6930 declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6931</pre>
6932
6933<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6934 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6935 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6936 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6937 declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6938</pre>
6939
6940<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6941 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6942 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6943 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6944 declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6945</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6946
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6947<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6948<p>These intrinsics takes the signed or unsigned minimum or maximum of
6949 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6950 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6951
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6952<h5>Arguments:</h5>
6953<p>These intrinsics take two arguments, the first a pointer to an integer value
6954 and the second an integer value. The result is also an integer value. These
6955 integer types can have any bit width, but they must all have the same bit
6956 width. The targets may only lower integer representations they support.</p>
6957
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6958<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6959<p>These intrinsics does a series of operations atomically. They first load the
6960 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6961 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6962 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6963
6964<h5>Examples:</h5>
6965<pre>
6966%ptr = malloc i32
6967 store i32 7, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6968%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6969 <i>; yields {i32}:result0 = 7</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6970%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6971 <i>; yields {i32}:result1 = -2</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6972%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6973 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6974%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6975 <i>; yields {i32}:result3 = 8</i>
6976%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6977</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6978
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6979</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6980
6981<!-- ======================================================================= -->
6982<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6983 <a name="int_general">General Intrinsics</a>
6984</div>
6985
6986<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6987
6988<p>This class of intrinsics is designed to be generic and has no specific
6989 purpose.</p>
6990
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6991</div>
6992
6993<!-- _______________________________________________________________________ -->
6994<div class="doc_subsubsection">
6995 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6996</div>
6997
6998<div class="doc_text">
6999
7000<h5>Syntax:</h5>
7001<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]7002 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7003</pre>
7004
7005<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7006<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7007
7008<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7009<p>The first argument is a pointer to a value, the second is a pointer to a
7010 global string, the third is a pointer to a global string which is the source
7011 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7012
7013<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7014<p>This intrinsic allows annotation of local variables with arbitrary strings.
7015 This can be useful for special purpose optimizations that want to look for
7016 these annotations. These have no other defined use, they are ignored by code
7017 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7018
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7019</div>
7020
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7021<!-- _______________________________________________________________________ -->
7022<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7023 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7024</div>
7025
7026<div class="doc_text">
7027
7028<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7029<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7030 any integer bit width.</p>
7031
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7032<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]7033 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7034 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7035 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7036 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7037 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7038</pre>
7039
7040<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7041<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7042
7043<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7044<p>The first argument is an integer value (result of some expression), the
7045 second is a pointer to a global string, the third is a pointer to a global
7046 string which is the source file name, and the last argument is the line
7047 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7048
7049<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7050<p>This intrinsic allows annotations to be put on arbitrary expressions with
7051 arbitrary strings. This can be useful for special purpose optimizations that
7052 want to look for these annotations. These have no other defined use, they
7053 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7054
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7055</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7056
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7057<!-- _______________________________________________________________________ -->
7058<div class="doc_subsubsection">
7059 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7060</div>
7061
7062<div class="doc_text">
7063
7064<h5>Syntax:</h5>
7065<pre>
7066 declare void @llvm.trap()
7067</pre>
7068
7069<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7070<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7071
7072<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7073<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7074
7075<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7076<p>This intrinsics is lowered to the target dependent trap instruction. If the
7077 target does not have a trap instruction, this intrinsic will be lowered to
7078 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7079
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7080</div>
7081
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7082<!-- _______________________________________________________________________ -->
7083<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7084 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7085</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7086
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7087<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7088
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7089<h5>Syntax:</h5>
7090<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7091 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7092</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7093
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7094<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7095<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7096 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7097 ensure that it is placed on the stack before local variables.</p>
7098
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7099<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7100<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7101 arguments. The first argument is the value loaded from the stack
7102 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7103 that has enough space to hold the value of the guard.</p>
7104
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7105<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7106<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7107 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7108 stack. This is to ensure that if a local variable on the stack is
7109 overwritten, it will destroy the value of the guard. When the function exits,
7110 the guard on the stack is checked against the original guard. If they're
7111 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7112 function.</p>
7113
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7114</div>
7115
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7116<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7117<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7118<address>
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7123
7124 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7125 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7126 Last modified: $Date$
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Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7128
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7129</body>
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