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gerrit-public.fairphone.software / toolchain / llvm-project / f991bbb0c120b77f6b068b697b811bd81519f932 / . / 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">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]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>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill 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>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]58 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]59 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_floating">Floating Point Types</a></li>
61 <li><a href="#t_void">Void Type</a></li>
62 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]63 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]64 </ol>
65 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]66 <li><a href="#t_derived">Derived Types</a>
67 <ol>
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>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]86 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]87 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]88 <li><a href="#metadata">Embedded Metadata</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]89 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]90 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]91 <li><a href="#othervalues">Other Values</a>
92 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]94 </ol>
95 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]96 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
97 <ol>
98 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]99 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
100 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]101 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
102 Global Variable</a></li>
103 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
104 Global Variable</a></li>
105 </ol>
106 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]107 <li><a href="#instref">Instruction Reference</a>
108 <ol>
109 <li><a href="#terminators">Terminator Instructions</a>
110 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
112 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]113 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]114 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]115 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]116 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]117 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]118 </ol>
119 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]120 <li><a href="#binaryops">Binary Operations</a>
121 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]127 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]128 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
129 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
130 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]131 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
132 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
133 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]134 </ol>
135 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]136 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
137 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]138 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
139 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
140 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]141 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]142 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]143 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]146 <li><a href="#vectorops">Vector Operations</a>
147 <ol>
148 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
149 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
150 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]151 </ol>
152 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]153 <li><a href="#aggregateops">Aggregate Operations</a>
154 <ol>
155 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
156 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
157 </ol>
158 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]159 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]160 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]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>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]276 <li><a href="#int_memorymarkers">Memory Use Markers</a>
277 <ol>
278 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
279 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
280 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
281 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
282 </ol>
283 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]284 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]285 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]286 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]287 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]288 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]289 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]290 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]291 '<tt>llvm.trap</tt>' Intrinsic</a></li>
292 <li><a href="#int_stackprotector">
293 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]294 <li><a href="#int_objectsize">
295 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]296 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]297 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]298 </ol>
299 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]300</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]301
302<div class="doc_author">
303 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
304 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]305</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]306
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]307<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]308<div class="doc_section"> <a name="abstract">Abstract </a></div>
309<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]310
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]311<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]312
313<p>This document is a reference manual for the LLVM assembly language. LLVM is
314 a Static Single Assignment (SSA) based representation that provides type
315 safety, low-level operations, flexibility, and the capability of representing
316 'all' high-level languages cleanly. It is the common code representation
317 used throughout all phases of the LLVM compilation strategy.</p>
318
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]319</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]320
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]321<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]322<div class="doc_section"> <a name="introduction">Introduction</a> </div>
323<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]324
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]325<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]326
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]327<p>The LLVM code representation is designed to be used in three different forms:
328 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
329 for fast loading by a Just-In-Time compiler), and as a human readable
330 assembly language representation. This allows LLVM to provide a powerful
331 intermediate representation for efficient compiler transformations and
332 analysis, while providing a natural means to debug and visualize the
333 transformations. The three different forms of LLVM are all equivalent. This
334 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]335
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]336<p>The LLVM representation aims to be light-weight and low-level while being
337 expressive, typed, and extensible at the same time. It aims to be a
338 "universal IR" of sorts, by being at a low enough level that high-level ideas
339 may be cleanly mapped to it (similar to how microprocessors are "universal
340 IR's", allowing many source languages to be mapped to them). By providing
341 type information, LLVM can be used as the target of optimizations: for
342 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]343 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]344 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]345
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]346</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]347
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]348<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]349<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]350
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]351<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]352
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]353<p>It is important to note that this document describes 'well formed' LLVM
354 assembly language. There is a difference between what the parser accepts and
355 what is considered 'well formed'. For example, the following instruction is
356 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]357
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]358<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]359<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]360%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]361</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]362</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]363
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]364<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
365 LLVM infrastructure provides a verification pass that may be used to verify
366 that an LLVM module is well formed. This pass is automatically run by the
367 parser after parsing input assembly and by the optimizer before it outputs
368 bitcode. The violations pointed out by the verifier pass indicate bugs in
369 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]370
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]371</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]372
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]373<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]374
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]375<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]376<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]377<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]378
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]379<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]380
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]381<p>LLVM identifiers come in two basic types: global and local. Global
382 identifiers (functions, global variables) begin with the <tt>'@'</tt>
383 character. Local identifiers (register names, types) begin with
384 the <tt>'%'</tt> character. Additionally, there are three different formats
385 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]387<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]388 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]389 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
390 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
391 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
392 other characters in their names can be surrounded with quotes. Special
393 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
394 ASCII code for the character in hexadecimal. In this way, any character
395 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]396
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]397 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]398 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]399
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]400 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]401 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]402</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]403
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]404<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]405 don't need to worry about name clashes with reserved words, and the set of
406 reserved words may be expanded in the future without penalty. Additionally,
407 unnamed identifiers allow a compiler to quickly come up with a temporary
408 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]409
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]410<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]411 languages. There are keywords for different opcodes
412 ('<tt><a href="#i_add">add</a></tt>',
413 '<tt><a href="#i_bitcast">bitcast</a></tt>',
414 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
415 ('<tt><a href="#t_void">void</a></tt>',
416 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
417 reserved words cannot conflict with variable names, because none of them
418 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]419
420<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]421 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]422
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]423<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]424
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]425<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]426<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]427%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]428</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]429</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]430
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]431<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]432
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]433<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]434<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]435%result = <a href="#i_shl">shl</a> i32 %X, i8 3
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
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]439<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]440
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]441<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]442<pre>
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]443%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
444%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]445%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]446</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]447</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]449<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
450 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]451
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]452<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]453 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]454 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]455
456 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]457 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]458
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]459 <li>Unnamed temporaries are numbered sequentially</li>
460</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]461
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]462<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]463 demonstrating instructions, we will follow an instruction with a comment that
464 defines the type and name of value produced. Comments are shown in italic
465 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]466
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]467</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]468
469<!-- *********************************************************************** -->
470<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
471<!-- *********************************************************************** -->
472
473<!-- ======================================================================= -->
474<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
475</div>
476
477<div class="doc_text">
478
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]479<p>LLVM programs are composed of "Module"s, each of which is a translation unit
480 of the input programs. Each module consists of functions, global variables,
481 and symbol table entries. Modules may be combined together with the LLVM
482 linker, which merges function (and global variable) definitions, resolves
483 forward declarations, and merges symbol table entries. Here is an example of
484 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]485
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]486<div class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]487<pre>
488<i>; Declare the string constant as a global constant.</i>
489<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]490
491<i>; External declaration of the puts function</i>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]492<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493
494<i>; Definition of main function</i>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]495define i32 @main() { <i>; i32()* </i>
496 <i>; Convert [13 x i8]* to i8 *...</i>
497 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]498
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]499 <i>; Call puts function to write out the string to stdout.</i>
500 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
501 <a href="#i_ret">ret</a> i32 0<br>}<br>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]502</pre>
503</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]504
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]505<p>This example is made up of a <a href="#globalvars">global variable</a> named
506 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
507 a <a href="#functionstructure">function definition</a> for
508 "<tt>main</tt>".</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]509
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]510<p>In general, a module is made up of a list of global values, where both
511 functions and global variables are global values. Global values are
512 represented by a pointer to a memory location (in this case, a pointer to an
513 array of char, and a pointer to a function), and have one of the
514 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]515
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]516</div>
517
518<!-- ======================================================================= -->
519<div class="doc_subsection">
520 <a name="linkage">Linkage Types</a>
521</div>
522
523<div class="doc_text">
524
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]525<p>All Global Variables and Functions have one of the following types of
526 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]527
528<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]529 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]530 <dd>Global values with private linkage are only directly accessible by objects
531 in the current module. In particular, linking code into a module with an
532 private global value may cause the private to be renamed as necessary to
533 avoid collisions. Because the symbol is private to the module, all
534 references can be updated. This doesn't show up in any symbol table in the
535 object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]536
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]537 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]538 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere7f064e2009-08-24 04:32:16 +0000[diff] [blame]539 removed by the linker after evaluation. Note that (unlike private
540 symbols) linker_private symbols are subject to coalescing by the linker:
541 weak symbols get merged and redefinitions are rejected. However, unlike
542 normal strong symbols, they are removed by the linker from the final
543 linked image (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]544
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]545 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]546 <dd>Similar to private, but the value shows as a local symbol
547 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
548 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]549
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]550 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]551 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]552 into the object file corresponding to the LLVM module. They exist to
553 allow inlining and other optimizations to take place given knowledge of
554 the definition of the global, which is known to be somewhere outside the
555 module. Globals with <tt>available_externally</tt> linkage are allowed to
556 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
557 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]558
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]559 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]560 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]561 the same name when linkage occurs. This can be used to implement
562 some forms of inline functions, templates, or other code which must be
563 generated in each translation unit that uses it, but where the body may
564 be overridden with a more definitive definition later. Unreferenced
565 <tt>linkonce</tt> globals are allowed to be discarded. Note that
566 <tt>linkonce</tt> linkage does not actually allow the optimizer to
567 inline the body of this function into callers because it doesn't know if
568 this definition of the function is the definitive definition within the
569 program or whether it will be overridden by a stronger definition.
570 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
571 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]572
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]573 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]574 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
575 <tt>linkonce</tt> linkage, except that unreferenced globals with
576 <tt>weak</tt> linkage may not be discarded. This is used for globals that
577 are declared "weak" in C source code.</dd>
578
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]579 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]580 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
581 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
582 global scope.
583 Symbols with "<tt>common</tt>" linkage are merged in the same way as
584 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]585 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]586 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]587 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
588 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]589
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]590
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]591 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]592 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]593 pointer to array type. When two global variables with appending linkage
594 are linked together, the two global arrays are appended together. This is
595 the LLVM, typesafe, equivalent of having the system linker append together
596 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]599 <dd>The semantics of this linkage follow the ELF object file model: the symbol
600 is weak until linked, if not linked, the symbol becomes null instead of
601 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]602
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]603 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
604 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]605 <dd>Some languages allow differing globals to be merged, such as two functions
606 with different semantics. Other languages, such as <tt>C++</tt>, ensure
607 that only equivalent globals are ever merged (the "one definition rule" -
608 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
609 and <tt>weak_odr</tt> linkage types to indicate that the global will only
610 be merged with equivalent globals. These linkage types are otherwise the
611 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]612
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]613 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]614 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]615 visible, meaning that it participates in linkage and can be used to
616 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]617</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]618
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]619<p>The next two types of linkage are targeted for Microsoft Windows platform
620 only. They are designed to support importing (exporting) symbols from (to)
621 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]622
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]623<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]624 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]625 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]626 or variable via a global pointer to a pointer that is set up by the DLL
627 exporting the symbol. On Microsoft Windows targets, the pointer name is
628 formed by combining <code>__imp_</code> and the function or variable
629 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]630
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]631 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]632 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]633 pointer to a pointer in a DLL, so that it can be referenced with the
634 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
635 name is formed by combining <code>__imp_</code> and the function or
636 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]637</dl>
638
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]639<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
640 another module defined a "<tt>.LC0</tt>" variable and was linked with this
641 one, one of the two would be renamed, preventing a collision. Since
642 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
643 declarations), they are accessible outside of the current module.</p>
644
645<p>It is illegal for a function <i>declaration</i> to have any linkage type
646 other than "externally visible", <tt>dllimport</tt>
647 or <tt>extern_weak</tt>.</p>
648
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]649<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]650 or <tt>weak_odr</tt> linkages.</p>
651
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]652</div>
653
654<!-- ======================================================================= -->
655<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]656 <a name="callingconv">Calling Conventions</a>
657</div>
658
659<div class="doc_text">
660
661<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]662 and <a href="#i_invoke">invokes</a> can all have an optional calling
663 convention specified for the call. The calling convention of any pair of
664 dynamic caller/callee must match, or the behavior of the program is
665 undefined. The following calling conventions are supported by LLVM, and more
666 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]667
668<dl>
669 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]670 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]671 specified) matches the target C calling conventions. This calling
672 convention supports varargs function calls and tolerates some mismatch in
673 the declared prototype and implemented declaration of the function (as
674 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]675
676 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]677 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]678 (e.g. by passing things in registers). This calling convention allows the
679 target to use whatever tricks it wants to produce fast code for the
680 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]681 (Application Binary Interface).
682 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
683 when this convention is used.</a> This calling convention does not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]684 support varargs and requires the prototype of all callees to exactly match
685 the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]686
687 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]688 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]689 as possible under the assumption that the call is not commonly executed.
690 As such, these calls often preserve all registers so that the call does
691 not break any live ranges in the caller side. This calling convention
692 does not support varargs and requires the prototype of all callees to
693 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]694
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]695 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]696 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]697 target-specific calling conventions to be used. Target specific calling
698 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]699</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]700
701<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]702 support Pascal conventions or any other well-known target-independent
703 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]704
705</div>
706
707<!-- ======================================================================= -->
708<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]709 <a name="visibility">Visibility Styles</a>
710</div>
711
712<div class="doc_text">
713
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]714<p>All Global Variables and Functions have one of the following visibility
715 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]716
717<dl>
718 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]719 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]720 that the declaration is visible to other modules and, in shared libraries,
721 means that the declared entity may be overridden. On Darwin, default
722 visibility means that the declaration is visible to other modules. Default
723 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]724
725 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]726 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]727 object if they are in the same shared object. Usually, hidden visibility
728 indicates that the symbol will not be placed into the dynamic symbol
729 table, so no other module (executable or shared library) can reference it
730 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]731
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]732 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]733 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]734 the dynamic symbol table, but that references within the defining module
735 will bind to the local symbol. That is, the symbol cannot be overridden by
736 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]737</dl>
738
739</div>
740
741<!-- ======================================================================= -->
742<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]743 <a name="namedtypes">Named Types</a>
744</div>
745
746<div class="doc_text">
747
748<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]749 it easier to read the IR and make the IR more condensed (particularly when
750 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]751
752<div class="doc_code">
753<pre>
754%mytype = type { %mytype*, i32 }
755</pre>
756</div>
757
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]758<p>You may give a name to any <a href="#typesystem">type</a> except
759 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
760 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]761
762<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]763 and that you can therefore specify multiple names for the same type. This
764 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
765 uses structural typing, the name is not part of the type. When printing out
766 LLVM IR, the printer will pick <em>one name</em> to render all types of a
767 particular shape. This means that if you have code where two different
768 source types end up having the same LLVM type, that the dumper will sometimes
769 print the "wrong" or unexpected type. This is an important design point and
770 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]771
772</div>
773
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]774<!-- ======================================================================= -->
775<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]776 <a name="globalvars">Global Variables</a>
777</div>
778
779<div class="doc_text">
780
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]781<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]782 instead of run-time. Global variables may optionally be initialized, may
783 have an explicit section to be placed in, and may have an optional explicit
784 alignment specified. A variable may be defined as "thread_local", which
785 means that it will not be shared by threads (each thread will have a
786 separated copy of the variable). A variable may be defined as a global
787 "constant," which indicates that the contents of the variable
788 will <b>never</b> be modified (enabling better optimization, allowing the
789 global data to be placed in the read-only section of an executable, etc).
790 Note that variables that need runtime initialization cannot be marked
791 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]792
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]793<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
794 constant, even if the final definition of the global is not. This capability
795 can be used to enable slightly better optimization of the program, but
796 requires the language definition to guarantee that optimizations based on the
797 'constantness' are valid for the translation units that do not include the
798 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]799
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]800<p>As SSA values, global variables define pointer values that are in scope
801 (i.e. they dominate) all basic blocks in the program. Global variables
802 always define a pointer to their "content" type because they describe a
803 region of memory, and all memory objects in LLVM are accessed through
804 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]805
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]806<p>A global variable may be declared to reside in a target-specific numbered
807 address space. For targets that support them, address spaces may affect how
808 optimizations are performed and/or what target instructions are used to
809 access the variable. The default address space is zero. The address space
810 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]811
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]812<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]813 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]814
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]815<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]816 the alignment is set to zero, the alignment of the global is set by the
817 target to whatever it feels convenient. If an explicit alignment is
818 specified, the global is forced to have at least that much alignment. All
819 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]820
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]821<p>For example, the following defines a global in a numbered address space with
822 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]823
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]824<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]825<pre>
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]826@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]827</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]828</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]829
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]830</div>
831
832
833<!-- ======================================================================= -->
834<div class="doc_subsection">
835 <a name="functionstructure">Functions</a>
836</div>
837
838<div class="doc_text">
839
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]840<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
841 optional <a href="#linkage">linkage type</a>, an optional
842 <a href="#visibility">visibility style</a>, an optional
843 <a href="#callingconv">calling convention</a>, a return type, an optional
844 <a href="#paramattrs">parameter attribute</a> for the return type, a function
845 name, a (possibly empty) argument list (each with optional
846 <a href="#paramattrs">parameter attributes</a>), optional
847 <a href="#fnattrs">function attributes</a>, an optional section, an optional
848 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
849 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]850
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]851<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
852 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]853 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]854 <a href="#callingconv">calling convention</a>, a return type, an optional
855 <a href="#paramattrs">parameter attribute</a> for the return type, a function
856 name, a possibly empty list of arguments, an optional alignment, and an
857 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]858
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]859<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]860 (Control Flow Graph) for the function. Each basic block may optionally start
861 with a label (giving the basic block a symbol table entry), contains a list
862 of instructions, and ends with a <a href="#terminators">terminator</a>
863 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]864
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]865<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]866 executed on entrance to the function, and it is not allowed to have
867 predecessor basic blocks (i.e. there can not be any branches to the entry
868 block of a function). Because the block can have no predecessors, it also
869 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]870
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]871<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]872 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]873
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]874<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]875 the alignment is set to zero, the alignment of the function is set by the
876 target to whatever it feels convenient. If an explicit alignment is
877 specified, the function is forced to have at least that much alignment. All
878 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]879
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]880<h5>Syntax:</h5>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]881<div class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]882<pre>
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]883define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]884 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
885 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
886 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
887 [<a href="#gc">gc</a>] { ... }
888</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]889</div>
890
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]891</div>
892
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]893<!-- ======================================================================= -->
894<div class="doc_subsection">
895 <a name="aliasstructure">Aliases</a>
896</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]897
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]898<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]899
900<p>Aliases act as "second name" for the aliasee value (which can be either
901 function, global variable, another alias or bitcast of global value). Aliases
902 may have an optional <a href="#linkage">linkage type</a>, and an
903 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]904
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]905<h5>Syntax:</h5>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]906<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]907<pre>
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]908@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]909</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]910</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]911
912</div>
913
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]914<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]915<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]916
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]917<div class="doc_text">
918
919<p>The return type and each parameter of a function type may have a set of
920 <i>parameter attributes</i> associated with them. Parameter attributes are
921 used to communicate additional information about the result or parameters of
922 a function. Parameter attributes are considered to be part of the function,
923 not of the function type, so functions with different parameter attributes
924 can have the same function type.</p>
925
926<p>Parameter attributes are simple keywords that follow the type specified. If
927 multiple parameter attributes are needed, they are space separated. For
928 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]929
930<div class="doc_code">
931<pre>
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]932declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]933declare i32 @atoi(i8 zeroext)
934declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]935</pre>
936</div>
937
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]938<p>Note that any attributes for the function result (<tt>nounwind</tt>,
939 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]940
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]941<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]942
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]943<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]944 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]945 <dd>This indicates to the code generator that the parameter or return value
946 should be zero-extended to a 32-bit value by the caller (for a parameter)
947 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]948
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]949 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]950 <dd>This indicates to the code generator that the parameter or return value
951 should be sign-extended to a 32-bit value by the caller (for a parameter)
952 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]953
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]954 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]955 <dd>This indicates that this parameter or return value should be treated in a
956 special target-dependent fashion during while emitting code for a function
957 call or return (usually, by putting it in a register as opposed to memory,
958 though some targets use it to distinguish between two different kinds of
959 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]960
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]961 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]962 <dd>This indicates that the pointer parameter should really be passed by value
963 to the function. The attribute implies that a hidden copy of the pointee
964 is made between the caller and the callee, so the callee is unable to
965 modify the value in the callee. This attribute is only valid on LLVM
966 pointer arguments. It is generally used to pass structs and arrays by
967 value, but is also valid on pointers to scalars. The copy is considered
968 to belong to the caller not the callee (for example,
969 <tt><a href="#readonly">readonly</a></tt> functions should not write to
970 <tt>byval</tt> parameters). This is not a valid attribute for return
971 values. The byval attribute also supports specifying an alignment with
972 the align attribute. This has a target-specific effect on the code
973 generator that usually indicates a desired alignment for the synthesized
974 stack slot.</dd>
975
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]976 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]977 <dd>This indicates that the pointer parameter specifies the address of a
978 structure that is the return value of the function in the source program.
979 This pointer must be guaranteed by the caller to be valid: loads and
980 stores to the structure may be assumed by the callee to not to trap. This
981 may only be applied to the first parameter. This is not a valid attribute
982 for return values. </dd>
983
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]984 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]985 <dd>This indicates that the pointer does not alias any global or any other
986 parameter. The caller is responsible for ensuring that this is the
987 case. On a function return value, <tt>noalias</tt> additionally indicates
988 that the pointer does not alias any other pointers visible to the
989 caller. For further details, please see the discussion of the NoAlias
990 response in
991 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
992 analysis</a>.</dd>
993
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]994 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]995 <dd>This indicates that the callee does not make any copies of the pointer
996 that outlive the callee itself. This is not a valid attribute for return
997 values.</dd>
998
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]999 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1000 <dd>This indicates that the pointer parameter can be excised using the
1001 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1002 attribute for return values.</dd>
1003</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1004
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1005</div>
1006
1007<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1008<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1009 <a name="gc">Garbage Collector Names</a>
1010</div>
1011
1012<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1013
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1014<p>Each function may specify a garbage collector name, which is simply a
1015 string:</p>
1016
1017<div class="doc_code">
1018<pre>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1019define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1020</pre>
1021</div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1022
1023<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1024 collector which will cause the compiler to alter its output in order to
1025 support the named garbage collection algorithm.</p>
1026
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1027</div>
1028
1029<!-- ======================================================================= -->
1030<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1031 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1032</div>
1033
1034<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1035
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1036<p>Function attributes are set to communicate additional information about a
1037 function. Function attributes are considered to be part of the function, not
1038 of the function type, so functions with different parameter attributes can
1039 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1040
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1041<p>Function attributes are simple keywords that follow the type specified. If
1042 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1043
1044<div class="doc_code">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1045<pre>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1046define void @f() noinline { ... }
1047define void @f() alwaysinline { ... }
1048define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1049define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1050</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1051</div>
1052
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1053<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1054 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1055 <dd>This attribute indicates that the inliner should attempt to inline this
1056 function into callers whenever possible, ignoring any active inlining size
1057 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1058
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1059 <dt><tt><b>inlinehint</b></tt></dt>
Dale Johannesen2aaf5392009-08-26 01:08:21 +0000[diff] [blame]1060 <dd>This attribute indicates that the source code contained a hint that inlining
1061 this function is desirable (such as the "inline" keyword in C/C++). It
1062 is just a hint; it imposes no requirements on the inliner.</dd>
1063
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1064 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1065 <dd>This attribute indicates that the inliner should never inline this
1066 function in any situation. This attribute may not be used together with
1067 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1068
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1069 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1070 <dd>This attribute suggests that optimization passes and code generator passes
1071 make choices that keep the code size of this function low, and otherwise
1072 do optimizations specifically to reduce code size.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1073
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1074 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1075 <dd>This function attribute indicates that the function never returns
1076 normally. This produces undefined behavior at runtime if the function
1077 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1078
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1079 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1080 <dd>This function attribute indicates that the function never returns with an
1081 unwind or exceptional control flow. If the function does unwind, its
1082 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1083
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1084 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1085 <dd>This attribute indicates that the function computes its result (or decides
1086 to unwind an exception) based strictly on its arguments, without
1087 dereferencing any pointer arguments or otherwise accessing any mutable
1088 state (e.g. memory, control registers, etc) visible to caller functions.
1089 It does not write through any pointer arguments
1090 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1091 changes any state visible to callers. This means that it cannot unwind
1092 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1093 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1094
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1095 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1096 <dd>This attribute indicates that the function does not write through any
1097 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1098 arguments) or otherwise modify any state (e.g. memory, control registers,
1099 etc) visible to caller functions. It may dereference pointer arguments
1100 and read state that may be set in the caller. A readonly function always
1101 returns the same value (or unwinds an exception identically) when called
1102 with the same set of arguments and global state. It cannot unwind an
1103 exception by calling the <tt>C++</tt> exception throwing methods, but may
1104 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1105
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1106 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1107 <dd>This attribute indicates that the function should emit a stack smashing
1108 protector. It is in the form of a "canary"&mdash;a random value placed on
1109 the stack before the local variables that's checked upon return from the
1110 function to see if it has been overwritten. A heuristic is used to
1111 determine if a function needs stack protectors or not.<br>
1112<br>
1113 If a function that has an <tt>ssp</tt> attribute is inlined into a
1114 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1115 function will have an <tt>ssp</tt> attribute.</dd>
1116
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1117 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1118 <dd>This attribute indicates that the function should <em>always</em> emit a
1119 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1120 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1121<br>
1122 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1123 function that doesn't have an <tt>sspreq</tt> attribute or which has
1124 an <tt>ssp</tt> attribute, then the resulting function will have
1125 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1126
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1127 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1128 <dd>This attribute indicates that the code generator should not use a red
1129 zone, even if the target-specific ABI normally permits it.</dd>
1130
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1131 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1132 <dd>This attributes disables implicit floating point instructions.</dd>
1133
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1134 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1135 <dd>This attribute disables prologue / epilogue emission for the function.
1136 This can have very system-specific consequences.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1137</dl>
1138
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1139</div>
1140
1141<!-- ======================================================================= -->
1142<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1143 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1144</div>
1145
1146<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1147
1148<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1149 the GCC "file scope inline asm" blocks. These blocks are internally
1150 concatenated by LLVM and treated as a single unit, but may be separated in
1151 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1152
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1153<div class="doc_code">
1154<pre>
1155module asm "inline asm code goes here"
1156module asm "more can go here"
1157</pre>
1158</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1159
1160<p>The strings can contain any character by escaping non-printable characters.
1161 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1162 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1163
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1164<p>The inline asm code is simply printed to the machine code .s file when
1165 assembly code is generated.</p>
1166
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1167</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1168
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1169<!-- ======================================================================= -->
1170<div class="doc_subsection">
1171 <a name="datalayout">Data Layout</a>
1172</div>
1173
1174<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1175
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1176<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1177 data is to be laid out in memory. The syntax for the data layout is
1178 simply:</p>
1179
1180<div class="doc_code">
1181<pre>
1182target datalayout = "<i>layout specification</i>"
1183</pre>
1184</div>
1185
1186<p>The <i>layout specification</i> consists of a list of specifications
1187 separated by the minus sign character ('-'). Each specification starts with
1188 a letter and may include other information after the letter to define some
1189 aspect of the data layout. The specifications accepted are as follows:</p>
1190
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1191<dl>
1192 <dt><tt>E</tt></dt>
1193 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1194 bits with the most significance have the lowest address location.</dd>
1195
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1196 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1197 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1198 the bits with the least significance have the lowest address
1199 location.</dd>
1200
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1201 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1202 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1203 <i>preferred</i> alignments. All sizes are in bits. Specifying
1204 the <i>pref</i> alignment is optional. If omitted, the
1205 preceding <tt>:</tt> should be omitted too.</dd>
1206
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1207 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1208 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1209 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1210
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1211 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1212 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1213 <i>size</i>.</dd>
1214
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1215 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1216 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1217 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1218 (double).</dd>
1219
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1220 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1221 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1222 <i>size</i>.</dd>
1223
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1224 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1225 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1226 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1227
1228 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1229 <dd>This specifies a set of native integer widths for the target CPU
1230 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1231 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1232 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1233 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1234</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1235
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1236<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1237 default set of specifications which are then (possibly) overriden by the
1238 specifications in the <tt>datalayout</tt> keyword. The default specifications
1239 are given in this list:</p>
1240
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1241<ul>
1242 <li><tt>E</tt> - big endian</li>
1243 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1244 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1245 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1246 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1247 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1248 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1249 alignment of 64-bits</li>
1250 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1251 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1252 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1253 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1254 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1255 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1256</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1257
1258<p>When LLVM is determining the alignment for a given type, it uses the
1259 following rules:</p>
1260
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1261<ol>
1262 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1263 specification is used.</li>
1264
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1265 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1266 smallest integer type that is larger than the bitwidth of the sought type
1267 is used. If none of the specifications are larger than the bitwidth then
1268 the the largest integer type is used. For example, given the default
1269 specifications above, the i7 type will use the alignment of i8 (next
1270 largest) while both i65 and i256 will use the alignment of i64 (largest
1271 specified).</li>
1272
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1273 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1274 largest vector type that is smaller than the sought vector type will be
1275 used as a fall back. This happens because &lt;128 x double&gt; can be
1276 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1277</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1278
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1279</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1280
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1281<!-- ======================================================================= -->
1282<div class="doc_subsection">
1283 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1284</div>
1285
1286<div class="doc_text">
1287
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1288<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1289with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1290is undefined. Pointer values are associated with address ranges
1291according to the following rules:</p>
1292
1293<ul>
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1294 <li>A pointer value formed from a
1295 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1296 is associated with the addresses associated with the first operand
1297 of the <tt>getelementptr</tt>.</li>
1298 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1299 range of the variable's storage.</li>
1300 <li>The result value of an allocation instruction is associated with
1301 the address range of the allocated storage.</li>
1302 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1303 no address.</li>
1304 <li>A pointer value formed by an
1305 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1306 address ranges of all pointer values that contribute (directly or
1307 indirectly) to the computation of the pointer's value.</li>
1308 <li>The result value of a
1309 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1310 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1311 <li>An integer constant other than zero or a pointer value returned
1312 from a function not defined within LLVM may be associated with address
1313 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1314 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1315 allocated by mechanisms provided by LLVM.</li>
1316 </ul>
1317
1318<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1319<tt><a href="#i_load">load</a></tt> merely indicates the size and
1320alignment of the memory from which to load, as well as the
1321interpretation of the value. The first operand of a
1322<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1323and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1324
1325<p>Consequently, type-based alias analysis, aka TBAA, aka
1326<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1327LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1328additional information which specialized optimization passes may use
1329to implement type-based alias analysis.</p>
1330
1331</div>
1332
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1333<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1334<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1335<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1336
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1337<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1338
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1339<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1340 intermediate representation. Being typed enables a number of optimizations
1341 to be performed on the intermediate representation directly, without having
1342 to do extra analyses on the side before the transformation. A strong type
1343 system makes it easier to read the generated code and enables novel analyses
1344 and transformations that are not feasible to perform on normal three address
1345 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1346
1347</div>
1348
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1349<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1350<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1351Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1352
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1353<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1354
1355<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1356
1357<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1358 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1359 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1360 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1361 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1362 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1363 </tr>
1364 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1365 <td><a href="#t_floating">floating point</a></td>
1366 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1367 </tr>
1368 <tr>
1369 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1370 <td><a href="#t_integer">integer</a>,
1371 <a href="#t_floating">floating point</a>,
1372 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1373 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1374 <a href="#t_struct">structure</a>,
1375 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1376 <a href="#t_label">label</a>,
1377 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1378 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1379 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1380 <tr>
1381 <td><a href="#t_primitive">primitive</a></td>
1382 <td><a href="#t_label">label</a>,
1383 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1384 <a href="#t_floating">floating point</a>,
1385 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1386 </tr>
1387 <tr>
1388 <td><a href="#t_derived">derived</a></td>
1389 <td><a href="#t_integer">integer</a>,
1390 <a href="#t_array">array</a>,
1391 <a href="#t_function">function</a>,
1392 <a href="#t_pointer">pointer</a>,
1393 <a href="#t_struct">structure</a>,
1394 <a href="#t_pstruct">packed structure</a>,
1395 <a href="#t_vector">vector</a>,
1396 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1397 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1398 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1399 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1400</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1401
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1402<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1403 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1404 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1405
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1406</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1407
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1408<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1409<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1410
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1411<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1412
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1413<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1414 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1415
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1416</div>
1417
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1418<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1419<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1420
1421<div class="doc_text">
1422
1423<h5>Overview:</h5>
1424<p>The integer type is a very simple type that simply specifies an arbitrary
1425 bit width for the integer type desired. Any bit width from 1 bit to
1426 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1427
1428<h5>Syntax:</h5>
1429<pre>
1430 iN
1431</pre>
1432
1433<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1434 value.</p>
1435
1436<h5>Examples:</h5>
1437<table class="layout">
1438 <tr class="layout">
1439 <td class="left"><tt>i1</tt></td>
1440 <td class="left">a single-bit integer.</td>
1441 </tr>
1442 <tr class="layout">
1443 <td class="left"><tt>i32</tt></td>
1444 <td class="left">a 32-bit integer.</td>
1445 </tr>
1446 <tr class="layout">
1447 <td class="left"><tt>i1942652</tt></td>
1448 <td class="left">a really big integer of over 1 million bits.</td>
1449 </tr>
1450</table>
1451
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1452</div>
1453
1454<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1455<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1456
1457<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1458
1459<table>
1460 <tbody>
1461 <tr><th>Type</th><th>Description</th></tr>
1462 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1463 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1464 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1465 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1466 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1467 </tbody>
1468</table>
1469
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1470</div>
1471
1472<!-- _______________________________________________________________________ -->
1473<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1474
1475<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1476
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1477<h5>Overview:</h5>
1478<p>The void type does not represent any value and has no size.</p>
1479
1480<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1481<pre>
1482 void
1483</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1484
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1485</div>
1486
1487<!-- _______________________________________________________________________ -->
1488<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1489
1490<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1491
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1492<h5>Overview:</h5>
1493<p>The label type represents code labels.</p>
1494
1495<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1496<pre>
1497 label
1498</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1499
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1500</div>
1501
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1502<!-- _______________________________________________________________________ -->
1503<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1504
1505<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1506
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1507<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1508<p>The metadata type represents embedded metadata. No derived types may be
1509 created from metadata except for <a href="#t_function">function</a>
1510 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1511
1512<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1513<pre>
1514 metadata
1515</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1516
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1517</div>
1518
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1519
1520<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1521<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1522
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1523<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1524
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1525<p>The real power in LLVM comes from the derived types in the system. This is
1526 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1527 useful types. Each of these types contain one or more element types which
1528 may be a primitive type, or another derived type. For example, it is
1529 possible to have a two dimensional array, using an array as the element type
1530 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1531
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1532</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1533
1534<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1535<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1536
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1537<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1538
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1539<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1540<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1541 sequentially in memory. The array type requires a size (number of elements)
1542 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1543
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1544<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1545<pre>
1546 [&lt;# elements&gt; x &lt;elementtype&gt;]
1547</pre>
1548
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1549<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1550 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1551
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1552<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1553<table class="layout">
1554 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1555 <td class="left"><tt>[40 x i32]</tt></td>
1556 <td class="left">Array of 40 32-bit integer values.</td>
1557 </tr>
1558 <tr class="layout">
1559 <td class="left"><tt>[41 x i32]</tt></td>
1560 <td class="left">Array of 41 32-bit integer values.</td>
1561 </tr>
1562 <tr class="layout">
1563 <td class="left"><tt>[4 x i8]</tt></td>
1564 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1565 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1566</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1567<p>Here are some examples of multidimensional arrays:</p>
1568<table class="layout">
1569 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1570 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1571 <td class="left">3x4 array of 32-bit integer values.</td>
1572 </tr>
1573 <tr class="layout">
1574 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1575 <td class="left">12x10 array of single precision floating point values.</td>
1576 </tr>
1577 <tr class="layout">
1578 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1579 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1580 </tr>
1581</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1582
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1583<p>There is no restriction on indexing beyond the end of the array implied by
1584 a static type (though there are restrictions on indexing beyond the bounds
1585 of an allocated object in some cases). This means that single-dimension
1586 'variable sized array' addressing can be implemented in LLVM with a zero
1587 length array type. An implementation of 'pascal style arrays' in LLVM could
1588 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1589
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1590</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1591
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1592<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1593<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1594
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1595<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1596
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1597<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1598<p>The function type can be thought of as a function signature. It consists of
1599 a return type and a list of formal parameter types. The return type of a
1600 function type is a scalar type, a void type, or a struct type. If the return
1601 type is a struct type then all struct elements must be of first class types,
1602 and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1603
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1604<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1605<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1606 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1607</pre>
1608
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1609<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1610 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1611 which indicates that the function takes a variable number of arguments.
1612 Variable argument functions can access their arguments with
1613 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1614 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1615 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1616
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1617<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1618<table class="layout">
1619 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1620 <td class="left"><tt>i32 (i32)</tt></td>
1621 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1622 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1623 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1624 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1625 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1626 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1627 an <tt>i16</tt> that should be sign extended and a
1628 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1629 <tt>float</tt>.
1630 </td>
1631 </tr><tr class="layout">
1632 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1633 <td class="left">A vararg function that takes at least one
1634 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1635 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1636 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1637 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1638 </tr><tr class="layout">
1639 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1640 <td class="left">A function taking an <tt>i32</tt>, returning a
1641 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1642 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1643 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1644</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1645
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1646</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1647
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1648<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1649<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1650
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1651<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1652
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1653<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1654<p>The structure type is used to represent a collection of data members together
1655 in memory. The packing of the field types is defined to match the ABI of the
1656 underlying processor. The elements of a structure may be any type that has a
1657 size.</p>
1658
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame^]1659<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1660 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1661 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1662 Structures in registers are accessed using the
1663 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1664 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1665<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1666<pre>
1667 { &lt;type list&gt; }
1668</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1669
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1670<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1671<table class="layout">
1672 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1673 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1674 <td class="left">A triple of three <tt>i32</tt> values</td>
1675 </tr><tr class="layout">
1676 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1677 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1678 second element is a <a href="#t_pointer">pointer</a> to a
1679 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1680 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1681 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1682</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1683
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1684</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1685
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1686<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1687<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1688</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1689
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1690<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1691
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1692<h5>Overview:</h5>
1693<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1694 together in memory. There is no padding between fields. Further, the
1695 alignment of a packed structure is 1 byte. The elements of a packed
1696 structure may be any type that has a size.</p>
1697
1698<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1699 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1700 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1701
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1702<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1703<pre>
1704 &lt; { &lt;type list&gt; } &gt;
1705</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1706
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1707<h5>Examples:</h5>
1708<table class="layout">
1709 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1710 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1711 <td class="left">A triple of three <tt>i32</tt> values</td>
1712 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1713 <td class="left">
1714<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1715 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1716 second element is a <a href="#t_pointer">pointer</a> to a
1717 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1718 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1719 </tr>
1720</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1721
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1722</div>
1723
1724<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1725<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1726
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1727<div class="doc_text">
1728
1729<h5>Overview:</h5>
1730<p>As in many languages, the pointer type represents a pointer or reference to
1731 another object, which must live in memory. Pointer types may have an optional
1732 address space attribute defining the target-specific numbered address space
1733 where the pointed-to object resides. The default address space is zero.</p>
1734
1735<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1736 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1737
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1738<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1739<pre>
1740 &lt;type&gt; *
1741</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1742
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1743<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1744<table class="layout">
1745 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1746 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1747 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1748 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1749 </tr>
1750 <tr class="layout">
1751 <td class="left"><tt>i32 (i32 *) *</tt></td>
1752 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1753 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1754 <tt>i32</tt>.</td>
1755 </tr>
1756 <tr class="layout">
1757 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1758 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1759 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1760 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1761</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1762
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1763</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1764
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1765<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1766<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1767
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1768<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1769
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1770<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1771<p>A vector type is a simple derived type that represents a vector of elements.
1772 Vector types are used when multiple primitive data are operated in parallel
1773 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1774 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1775 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1776
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1777<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1778<pre>
1779 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1780</pre>
1781
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1782<p>The number of elements is a constant integer value; elementtype may be any
1783 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1784
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1785<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1786<table class="layout">
1787 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1788 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1789 <td class="left">Vector of 4 32-bit integer values.</td>
1790 </tr>
1791 <tr class="layout">
1792 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1793 <td class="left">Vector of 8 32-bit floating-point values.</td>
1794 </tr>
1795 <tr class="layout">
1796 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1797 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1798 </tr>
1799</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1800
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1801</div>
1802
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1803<!-- _______________________________________________________________________ -->
1804<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1805<div class="doc_text">
1806
1807<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1808<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1809 corresponds (for example) to the C notion of a forward declared structure
1810 type. In LLVM, opaque types can eventually be resolved to any type (not just
1811 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1812
1813<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1814<pre>
1815 opaque
1816</pre>
1817
1818<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1819<table class="layout">
1820 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1821 <td class="left"><tt>opaque</tt></td>
1822 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1823 </tr>
1824</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1825
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1826</div>
1827
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1828<!-- ======================================================================= -->
1829<div class="doc_subsection">
1830 <a name="t_uprefs">Type Up-references</a>
1831</div>
1832
1833<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1834
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1835<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1836<p>An "up reference" allows you to refer to a lexically enclosing type without
1837 requiring it to have a name. For instance, a structure declaration may
1838 contain a pointer to any of the types it is lexically a member of. Example
1839 of up references (with their equivalent as named type declarations)
1840 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1841
1842<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1843 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1844 { \2 }* %y = type { %y }*
1845 \1* %z = type %z*
1846</pre>
1847
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1848<p>An up reference is needed by the asmprinter for printing out cyclic types
1849 when there is no declared name for a type in the cycle. Because the
1850 asmprinter does not want to print out an infinite type string, it needs a
1851 syntax to handle recursive types that have no names (all names are optional
1852 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1853
1854<h5>Syntax:</h5>
1855<pre>
1856 \&lt;level&gt;
1857</pre>
1858
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1859<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]1860
1861<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1862<table class="layout">
1863 <tr class="layout">
1864 <td class="left"><tt>\1*</tt></td>
1865 <td class="left">Self-referential pointer.</td>
1866 </tr>
1867 <tr class="layout">
1868 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1869 <td class="left">Recursive structure where the upref refers to the out-most
1870 structure.</td>
1871 </tr>
1872</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1873
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1874</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1875
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1876<!-- *********************************************************************** -->
1877<div class="doc_section"> <a name="constants">Constants</a> </div>
1878<!-- *********************************************************************** -->
1879
1880<div class="doc_text">
1881
1882<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1883 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1884
1885</div>
1886
1887<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1888<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1889
1890<div class="doc_text">
1891
1892<dl>
1893 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1894 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1895 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1896
1897 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1898 <dd>Standard integers (such as '4') are constants of
1899 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1900 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1901
1902 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1903 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1904 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1905 notation (see below). The assembler requires the exact decimal value of a
1906 floating-point constant. For example, the assembler accepts 1.25 but
1907 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1908 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1909
1910 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1911 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1912 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1913</dl>
1914
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1915<p>The one non-intuitive notation for constants is the hexadecimal form of
1916 floating point constants. For example, the form '<tt>double
1917 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1918 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1919 constants are required (and the only time that they are generated by the
1920 disassembler) is when a floating point constant must be emitted but it cannot
1921 be represented as a decimal floating point number in a reasonable number of
1922 digits. For example, NaN's, infinities, and other special values are
1923 represented in their IEEE hexadecimal format so that assembly and disassembly
1924 do not cause any bits to change in the constants.</p>
1925
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]1926<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1927 represented using the 16-digit form shown above (which matches the IEEE754
1928 representation for double); float values must, however, be exactly
1929 representable as IEE754 single precision. Hexadecimal format is always used
1930 for long double, and there are three forms of long double. The 80-bit format
1931 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1932 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1933 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1934 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1935 currently supported target uses this format. Long doubles will only work if
1936 they match the long double format on your target. All hexadecimal formats
1937 are big-endian (sign bit at the left).</p>
1938
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1939</div>
1940
1941<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]1942<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]1943<a name="aggregateconstants"></a> <!-- old anchor -->
1944<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1945</div>
1946
1947<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1948
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]1949<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1950 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1951
1952<dl>
1953 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1954 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1955 type definitions (a comma separated list of elements, surrounded by braces
1956 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1957 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1958 Structure constants must have <a href="#t_struct">structure type</a>, and
1959 the number and types of elements must match those specified by the
1960 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1961
1962 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1963 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1964 definitions (a comma separated list of elements, surrounded by square
1965 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1966 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1967 the number and types of elements must match those specified by the
1968 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1969
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1970 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1971 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1972 definitions (a comma separated list of elements, surrounded by
1973 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1974 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1975 have <a href="#t_vector">vector type</a>, and the number and types of
1976 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1977
1978 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1979 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1980 value to zero of <em>any</em> type, including scalar and aggregate types.
1981 This is often used to avoid having to print large zero initializers
1982 (e.g. for large arrays) and is always exactly equivalent to using explicit
1983 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]1984
1985 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]1986 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1987 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1988 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1989 be interpreted as part of the instruction stream, metadata is a place to
1990 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1991</dl>
1992
1993</div>
1994
1995<!-- ======================================================================= -->
1996<div class="doc_subsection">
1997 <a name="globalconstants">Global Variable and Function Addresses</a>
1998</div>
1999
2000<div class="doc_text">
2001
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2002<p>The addresses of <a href="#globalvars">global variables</a>
2003 and <a href="#functionstructure">functions</a> are always implicitly valid
2004 (link-time) constants. These constants are explicitly referenced when
2005 the <a href="#identifiers">identifier for the global</a> is used and always
2006 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2007 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2008
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2009<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2010<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2011@X = global i32 17
2012@Y = global i32 42
2013@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2014</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2015</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2016
2017</div>
2018
2019<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2020<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2021<div class="doc_text">
2022
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2023<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2024 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2025 Undefined values may be of any type (other than label or void) and be used
2026 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2027
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2028<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2029 program is well defined no matter what value is used. This gives the
2030 compiler more freedom to optimize. Here are some examples of (potentially
2031 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2032
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2033
2034<div class="doc_code">
2035<pre>
2036 %A = add %X, undef
2037 %B = sub %X, undef
2038 %C = xor %X, undef
2039Safe:
2040 %A = undef
2041 %B = undef
2042 %C = undef
2043</pre>
2044</div>
2045
2046<p>This is safe because all of the output bits are affected by the undef bits.
2047Any output bit can have a zero or one depending on the input bits.</p>
2048
2049<div class="doc_code">
2050<pre>
2051 %A = or %X, undef
2052 %B = and %X, undef
2053Safe:
2054 %A = -1
2055 %B = 0
2056Unsafe:
2057 %A = undef
2058 %B = undef
2059</pre>
2060</div>
2061
2062<p>These logical operations have bits that are not always affected by the input.
2063For example, if "%X" has a zero bit, then the output of the 'and' operation will
2064always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2065such, it is unsafe to optimize or assume that the result of the and is undef.
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2066However, it is safe to assume that all bits of the undef could be 0, and
2067optimize the and to 0. Likewise, it is safe to assume that all the bits of
2068the undef operand to the or could be set, allowing the or to be folded to
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2069-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2070
2071<div class="doc_code">
2072<pre>
2073 %A = select undef, %X, %Y
2074 %B = select undef, 42, %Y
2075 %C = select %X, %Y, undef
2076Safe:
2077 %A = %X (or %Y)
2078 %B = 42 (or %Y)
2079 %C = %Y
2080Unsafe:
2081 %A = undef
2082 %B = undef
2083 %C = undef
2084</pre>
2085</div>
2086
2087<p>This set of examples show that undefined select (and conditional branch)
2088conditions can go "either way" but they have to come from one of the two
2089operands. In the %A example, if %X and %Y were both known to have a clear low
2090bit, then %A would have to have a cleared low bit. However, in the %C example,
2091the optimizer is allowed to assume that the undef operand could be the same as
2092%Y, allowing the whole select to be eliminated.</p>
2093
2094
2095<div class="doc_code">
2096<pre>
2097 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2098
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2099 %B = undef
2100 %C = xor %B, %B
2101
2102 %D = undef
2103 %E = icmp lt %D, 4
2104 %F = icmp gte %D, 4
2105
2106Safe:
2107 %A = undef
2108 %B = undef
2109 %C = undef
2110 %D = undef
2111 %E = undef
2112 %F = undef
2113</pre>
2114</div>
2115
2116<p>This example points out that two undef operands are not necessarily the same.
2117This can be surprising to people (and also matches C semantics) where they
2118assume that "X^X" is always zero, even if X is undef. This isn't true for a
2119number of reasons, but the short answer is that an undef "variable" can
2120arbitrarily change its value over its "live range". This is true because the
2121"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2122logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2123so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2124to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2125would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2126
2127<div class="doc_code">
2128<pre>
2129 %A = fdiv undef, %X
2130 %B = fdiv %X, undef
2131Safe:
2132 %A = undef
2133b: unreachable
2134</pre>
2135</div>
2136
2137<p>These examples show the crucial difference between an <em>undefined
2138value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2139allowed to have an arbitrary bit-pattern. This means that the %A operation
2140can be constant folded to undef because the undef could be an SNaN, and fdiv is
2141not (currently) defined on SNaN's. However, in the second example, we can make
2142a more aggressive assumption: because the undef is allowed to be an arbitrary
2143value, 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]2144has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2145does not execute at all. This allows us to delete the divide and all code after
2146it: since the undefined operation "can't happen", the optimizer can assume that
2147it occurs in dead code.
2148</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2149
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2150<div class="doc_code">
2151<pre>
2152a: store undef -> %X
2153b: store %X -> undef
2154Safe:
2155a: &lt;deleted&gt;
2156b: unreachable
2157</pre>
2158</div>
2159
2160<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2161can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2162overwritten with bits that happen to match what was already there. However, a
2163store "to" an undefined location could clobber arbitrary memory, therefore, it
2164has undefined behavior.</p>
2165
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2166</div>
2167
2168<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2169<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2170 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2171<div class="doc_text">
2172
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2173<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2174
2175<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2176 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2177 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2178
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2179<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2180 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2181 against null. Pointer equality tests between labels addresses is undefined
2182 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2183 equal to the null pointer. This may also be passed around as an opaque
2184 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2185 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2186 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2187
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2188<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2189 using the value as the operand to an inline assembly, but that is target
2190 specific.
2191 </p>
2192
2193</div>
2194
2195
2196<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2197<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2198</div>
2199
2200<div class="doc_text">
2201
2202<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2203 to be used as constants. Constant expressions may be of
2204 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2205 operation that does not have side effects (e.g. load and call are not
2206 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2207
2208<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2209 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2210 <dd>Truncate a constant to another type. The bit size of CST must be larger
2211 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2212
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2213 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2214 <dd>Zero extend a constant to another type. The bit size of CST must be
2215 smaller or equal to the bit size of TYPE. Both types must be
2216 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2217
2218 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2219 <dd>Sign extend a constant to another type. The bit size of CST must be
2220 smaller or equal to the bit size of TYPE. Both types must be
2221 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2222
2223 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2224 <dd>Truncate a floating point constant to another floating point type. The
2225 size of CST must be larger than the size of TYPE. Both types must be
2226 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2227
2228 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2229 <dd>Floating point extend a constant to another type. The size of CST must be
2230 smaller or equal to the size of TYPE. Both types must be floating
2231 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2232
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]2233 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2234 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2235 constant. TYPE must be a scalar or vector integer type. CST must be of
2236 scalar or vector floating point type. Both CST and TYPE must be scalars,
2237 or vectors of the same number of elements. If the value won't fit in the
2238 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2239
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2240 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2241 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2242 constant. TYPE must be a scalar or vector integer type. CST must be of
2243 scalar or vector floating point type. Both CST and TYPE must be scalars,
2244 or vectors of the same number of elements. If the value won't fit in the
2245 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2246
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2247 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2248 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2249 constant. TYPE must be a scalar or vector floating point type. CST must be
2250 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2251 vectors of the same number of elements. If the value won't fit in the
2252 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2253
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2254 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2255 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2256 constant. TYPE must be a scalar or vector floating point type. CST must be
2257 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2258 vectors of the same number of elements. If the value won't fit in the
2259 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2260
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2261 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2262 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2263 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2264 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2265 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2266
2267 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2268 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2269 type. CST must be of integer type. The CST value is zero extended,
2270 truncated, or unchanged to make it fit in a pointer size. This one is
2271 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2272
2273 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2274 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2275 are the same as those for the <a href="#i_bitcast">bitcast
2276 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2277
2278 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]2279 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2280 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2281 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2282 instruction, the index list may have zero or more indexes, which are
2283 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2284
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2285 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2286 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2287
2288 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2289 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2290
2291 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2292 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2293
2294 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2295 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2296 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2297
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]2298 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2299 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2300 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2301
2302 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2303 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2304 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2305
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2306 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2307 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2308 be any of the <a href="#binaryops">binary</a>
2309 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2310 on operands are the same as those for the corresponding instruction
2311 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2312</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2313
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2314</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2315
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2316<!-- ======================================================================= -->
2317<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2318</div>
2319
2320<div class="doc_text">
2321
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2322<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2323 stream without affecting the behaviour of the program. There are two
2324 metadata primitives, strings and nodes. All metadata has the
2325 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2326 point ('<tt>!</tt>').</p>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2327
2328<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2329 any character by escaping non-printable characters with "\xx" where "xx" is
2330 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2331
2332<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2333 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2334 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2335 10}</tt>".</p>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2336
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2337<p>A metadata node will attempt to track changes to the values it holds. In the
2338 event that a value is deleted, it will be replaced with a typeless
2339 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckyb8f9b7a2009-05-10 20:57:05 +0000[diff] [blame]2340
Devang Patele3073482010-01-05 20:41:31 +0000[diff] [blame]2341<p>A named metadata is a collection of metadata nodes. For example: "<tt>!foo =
2342 metadata !{!4, !3}</tt>".
2343
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2344<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2345 the program that isn't available in the instructions, or that isn't easily
2346 computable. Similarly, the code generator may expect a certain metadata
2347 format to be used to express debugging information.</p>
2348
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2349</div>
2350
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2351<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2352<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2353<!-- *********************************************************************** -->
2354
2355<!-- ======================================================================= -->
2356<div class="doc_subsection">
2357<a name="inlineasm">Inline Assembler Expressions</a>
2358</div>
2359
2360<div class="doc_text">
2361
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2362<p>LLVM supports inline assembler expressions (as opposed
2363 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2364 a special value. This value represents the inline assembler as a string
2365 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2366 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2367 expression has side effects, and a flag indicating whether the function
2368 containing the asm needs to align its stack conservatively. An example
2369 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2370
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2371<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2372<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2373i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2374</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2375</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2376
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2377<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2378 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2379 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2380
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2381<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2382<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2383%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2384</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2385</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2386
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2387<p>Inline asms with side effects not visible in the constraint list must be
2388 marked as having side effects. This is done through the use of the
2389 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2390
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2391<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2392<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2393call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2394</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2395</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2396
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2397<p>In some cases inline asms will contain code that will not work unless the
2398 stack is aligned in some way, such as calls or SSE instructions on x86,
2399 yet will not contain code that does that alignment within the asm.
2400 The compiler should make conservative assumptions about what the asm might
2401 contain and should generate its usual stack alignment code in the prologue
2402 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2403
2404<div class="doc_code">
2405<pre>
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2406call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2407</pre>
2408</div>
2409
2410<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2411 first.</p>
2412
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2413<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2414 documented here. Constraints on what can be done (e.g. duplication, moving,
2415 etc need to be documented). This is probably best done by reference to
2416 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2417
2418</div>
2419
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2420
2421<!-- *********************************************************************** -->
2422<div class="doc_section">
2423 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2424</div>
2425<!-- *********************************************************************** -->
2426
2427<p>LLVM has a number of "magic" global variables that contain data that affect
2428code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2429of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2430section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2431by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2432
2433<!-- ======================================================================= -->
2434<div class="doc_subsection">
2435<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2436</div>
2437
2438<div class="doc_text">
2439
2440<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2441href="#linkage_appending">appending linkage</a>. This array contains a list of
2442pointers to global variables and functions which may optionally have a pointer
2443cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2444
2445<pre>
2446 @X = global i8 4
2447 @Y = global i32 123
2448
2449 @llvm.used = appending global [2 x i8*] [
2450 i8* @X,
2451 i8* bitcast (i32* @Y to i8*)
2452 ], section "llvm.metadata"
2453</pre>
2454
2455<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2456compiler, assembler, and linker are required to treat the symbol as if there is
2457a reference to the global that it cannot see. For example, if a variable has
2458internal linkage and no references other than that from the <tt>@llvm.used</tt>
2459list, it cannot be deleted. This is commonly used to represent references from
2460inline asms and other things the compiler cannot "see", and corresponds to
2461"attribute((used))" in GNU C.</p>
2462
2463<p>On some targets, the code generator must emit a directive to the assembler or
2464object file to prevent the assembler and linker from molesting the symbol.</p>
2465
2466</div>
2467
2468<!-- ======================================================================= -->
2469<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2470<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2471</div>
2472
2473<div class="doc_text">
2474
2475<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2476<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2477touching the symbol. On targets that support it, this allows an intelligent
2478linker to optimize references to the symbol without being impeded as it would be
2479by <tt>@llvm.used</tt>.</p>
2480
2481<p>This is a rare construct that should only be used in rare circumstances, and
2482should not be exposed to source languages.</p>
2483
2484</div>
2485
2486<!-- ======================================================================= -->
2487<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2488<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2489</div>
2490
2491<div class="doc_text">
2492
2493<p>TODO: Describe this.</p>
2494
2495</div>
2496
2497<!-- ======================================================================= -->
2498<div class="doc_subsection">
2499<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2500</div>
2501
2502<div class="doc_text">
2503
2504<p>TODO: Describe this.</p>
2505
2506</div>
2507
2508
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2509<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2510<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2511<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2512
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2513<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2514
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2515<p>The LLVM instruction set consists of several different classifications of
2516 instructions: <a href="#terminators">terminator
2517 instructions</a>, <a href="#binaryops">binary instructions</a>,
2518 <a href="#bitwiseops">bitwise binary instructions</a>,
2519 <a href="#memoryops">memory instructions</a>, and
2520 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2521
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2522</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2523
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2524<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2525<div class="doc_subsection"> <a name="terminators">Terminator
2526Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2527
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2528<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2529
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2530<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2531 in a program ends with a "Terminator" instruction, which indicates which
2532 block should be executed after the current block is finished. These
2533 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2534 control flow, not values (the one exception being the
2535 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2536
2537<p>There are six different terminator instructions: the
2538 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2539 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2540 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2541 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2542 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2543 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2544 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2545
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2546</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2547
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2548<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2549<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2550Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2551
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2552<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2553
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2554<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2555<pre>
2556 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2557 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2558</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2559
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2560<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2561<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2562 a value) from a function back to the caller.</p>
2563
2564<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2565 value and then causes control flow, and one that just causes control flow to
2566 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2567
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2568<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2569<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2570 return value. The type of the return value must be a
2571 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2572
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2573<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2574 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2575 value or a return value with a type that does not match its type, or if it
2576 has a void return type and contains a '<tt>ret</tt>' instruction with a
2577 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2578
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2579<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2580<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2581 the calling function's context. If the caller is a
2582 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2583 instruction after the call. If the caller was an
2584 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2585 the beginning of the "normal" destination block. If the instruction returns
2586 a value, that value shall set the call or invoke instruction's return
2587 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2588
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2589<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2590<pre>
2591 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2592 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2593 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2594</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2595
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2596</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2597<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2598<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2599
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2600<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2601
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2602<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2603<pre>
2604 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]2605</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2606
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2607<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2608<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2609 different basic block in the current function. There are two forms of this
2610 instruction, corresponding to a conditional branch and an unconditional
2611 branch.</p>
2612
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2613<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2614<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2615 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2616 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2617 target.</p>
2618
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2619<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2620<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2621 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2622 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2623 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2624
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2625<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2626<pre>
2627Test:
2628 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2629 br i1 %cond, label %IfEqual, label %IfUnequal
2630IfEqual:
2631 <a href="#i_ret">ret</a> i32 1
2632IfUnequal:
2633 <a href="#i_ret">ret</a> i32 0
2634</pre>
2635
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2636</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2637
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2638<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2639<div class="doc_subsubsection">
2640 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2641</div>
2642
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2643<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2644
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2645<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2646<pre>
2647 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2648</pre>
2649
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2650<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2651<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]2652 several different places. It is a generalization of the '<tt>br</tt>'
2653 instruction, allowing a branch to occur to one of many possible
2654 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2655
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2656<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2657<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2658 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2659 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2660 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2661
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2662<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2663<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2664 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2665 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2666 transferred to the corresponding destination; otherwise, control flow is
2667 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2668
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2669<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2670<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2671 <tt>switch</tt> instruction, this instruction may be code generated in
2672 different ways. For example, it could be generated as a series of chained
2673 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2674
2675<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2676<pre>
2677 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2678 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2679 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2680
2681 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2682 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2683
2684 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2685 switch i32 %val, label %otherwise [ i32 0, label %onzero
2686 i32 1, label %onone
2687 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2688</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2689
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2690</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2691
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2692
2693<!-- _______________________________________________________________________ -->
2694<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2695 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2696</div>
2697
2698<div class="doc_text">
2699
2700<h5>Syntax:</h5>
2701<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2702 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2703</pre>
2704
2705<h5>Overview:</h5>
2706
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2707<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2708 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2709 "<tt>address</tt>". Address must be derived from a <a
2710 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2711
2712<h5>Arguments:</h5>
2713
2714<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2715 rest of the arguments indicate the full set of possible destinations that the
2716 address may point to. Blocks are allowed to occur multiple times in the
2717 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2718
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2719<p>This destination list is required so that dataflow analysis has an accurate
2720 understanding of the CFG.</p>
2721
2722<h5>Semantics:</h5>
2723
2724<p>Control transfers to the block specified in the address argument. All
2725 possible destination blocks must be listed in the label list, otherwise this
2726 instruction has undefined behavior. This implies that jumps to labels
2727 defined in other functions have undefined behavior as well.</p>
2728
2729<h5>Implementation:</h5>
2730
2731<p>This is typically implemented with a jump through a register.</p>
2732
2733<h5>Example:</h5>
2734<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2735 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2736</pre>
2737
2738</div>
2739
2740
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2741<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2742<div class="doc_subsubsection">
2743 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2744</div>
2745
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2746<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2747
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2748<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2749<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2750 &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]2751 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2752</pre>
2753
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2754<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2755<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2756 function, with the possibility of control flow transfer to either the
2757 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2758 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2759 control flow will return to the "normal" label. If the callee (or any
2760 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2761 instruction, control is interrupted and continued at the dynamically nearest
2762 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2763
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2764<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2765<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2766
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2767<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2768 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2769 convention</a> the call should use. If none is specified, the call
2770 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2771
2772 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2773 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2774 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2775
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2776 <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]2777 function value being invoked. In most cases, this is a direct function
2778 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2779 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2780
2781 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2782 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2783
2784 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2785 signature argument types. If the function signature indicates the
2786 function accepts a variable number of arguments, the extra arguments can
2787 be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2788
2789 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2790 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2791
2792 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2793 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2794
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2795 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2796 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2797 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2798</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2799
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2800<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2801<p>This instruction is designed to operate as a standard
2802 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2803 primary difference is that it establishes an association with a label, which
2804 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2805
2806<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2807 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2808 exception. Additionally, this is important for implementation of
2809 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2810
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2811<p>For the purposes of the SSA form, the definition of the value returned by the
2812 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2813 block to the "normal" label. If the callee unwinds then no return value is
2814 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]2815
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2816<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2817<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2818 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2819 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2820 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2821 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2822</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2823
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2824</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2825
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2826<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2827
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2828<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2829Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2830
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2831<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2832
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2833<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2834<pre>
2835 unwind
2836</pre>
2837
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2838<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2839<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2840 at the first callee in the dynamic call stack which used
2841 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2842 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2843
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2844<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2845<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2846 immediately halt. The dynamic call stack is then searched for the
2847 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2848 Once found, execution continues at the "exceptional" destination block
2849 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2850 instruction in the dynamic call chain, undefined behavior results.</p>
2851
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2852</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2853
2854<!-- _______________________________________________________________________ -->
2855
2856<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2857Instruction</a> </div>
2858
2859<div class="doc_text">
2860
2861<h5>Syntax:</h5>
2862<pre>
2863 unreachable
2864</pre>
2865
2866<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2867<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2868 instruction is used to inform the optimizer that a particular portion of the
2869 code is not reachable. This can be used to indicate that the code after a
2870 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2871
2872<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2873<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2874
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2875</div>
2876
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2877<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2878<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2879
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2880<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2881
2882<p>Binary operators are used to do most of the computation in a program. They
2883 require two operands of the same type, execute an operation on them, and
2884 produce a single value. The operands might represent multiple data, as is
2885 the case with the <a href="#t_vector">vector</a> data type. The result value
2886 has the same type as its operands.</p>
2887
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2888<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2889
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2890</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2891
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2892<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2893<div class="doc_subsubsection">
2894 <a name="i_add">'<tt>add</tt>' Instruction</a>
2895</div>
2896
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2897<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2898
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2899<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2900<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]2901 &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]2902 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2903 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2904 &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]2905</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2906
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2907<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2908<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2909
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2910<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2911<p>The two arguments to the '<tt>add</tt>' instruction must
2912 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2913 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2914
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2915<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2916<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2917
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2918<p>If the sum has unsigned overflow, the result returned is the mathematical
2919 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]2920
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2921<p>Because LLVM integers use a two's complement representation, this instruction
2922 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2923
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2924<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2925 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2926 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2927 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]2928
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2929<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2930<pre>
2931 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2932</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2933
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2934</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2935
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2936<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2937<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2938 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2939</div>
2940
2941<div class="doc_text">
2942
2943<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2944<pre>
2945 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2946</pre>
2947
2948<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2949<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2950
2951<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2952<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2953 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2954 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2955
2956<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2957<p>The value produced is the floating point sum of the two operands.</p>
2958
2959<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2960<pre>
2961 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2962</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2963
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2964</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2965
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2966<!-- _______________________________________________________________________ -->
2967<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2968 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2969</div>
2970
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2971<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2972
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2973<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2974<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2975 &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]2976 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2977 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2978 &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]2979</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2980
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2981<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2982<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2983 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2984
2985<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2986 '<tt>neg</tt>' instruction present in most other intermediate
2987 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2988
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2989<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2990<p>The two arguments to the '<tt>sub</tt>' instruction must
2991 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2992 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2993
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2994<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2995<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2996
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2997<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2998 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2999 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3000
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3001<p>Because LLVM integers use a two's complement representation, this instruction
3002 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3003
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3004<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3005 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3006 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3007 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3008
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3009<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3010<pre>
3011 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3012 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3013</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3014
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3015</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3016
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3017<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3018<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3019 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3020</div>
3021
3022<div class="doc_text">
3023
3024<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3025<pre>
3026 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3027</pre>
3028
3029<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3030<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3031 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3032
3033<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3034 '<tt>fneg</tt>' instruction present in most other intermediate
3035 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3036
3037<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3038<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3039 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3040 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3041
3042<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3043<p>The value produced is the floating point difference of the two operands.</p>
3044
3045<h5>Example:</h5>
3046<pre>
3047 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3048 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3049</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3050
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3051</div>
3052
3053<!-- _______________________________________________________________________ -->
3054<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3055 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3056</div>
3057
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3058<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3059
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3060<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3061<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3062 &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]3063 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3064 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3065 &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]3066</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3067
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3068<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3069<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3070
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3071<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3072<p>The two arguments to the '<tt>mul</tt>' instruction must
3073 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3074 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3075
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3076<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3077<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3078
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3079<p>If the result of the multiplication has unsigned overflow, the result
3080 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3081 width of the result.</p>
3082
3083<p>Because LLVM integers use a two's complement representation, and the result
3084 is the same width as the operands, this instruction returns the correct
3085 result for both signed and unsigned integers. If a full product
3086 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3087 be sign-extended or zero-extended as appropriate to the width of the full
3088 product.</p>
3089
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3090<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3091 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3092 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3093 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3094
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3095<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3096<pre>
3097 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3098</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3099
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3100</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3101
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3102<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3103<div class="doc_subsubsection">
3104 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3105</div>
3106
3107<div class="doc_text">
3108
3109<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3110<pre>
3111 &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]3112</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3113
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3114<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3115<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3116
3117<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3118<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3119 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3120 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3121
3122<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3123<p>The value produced is the floating point product of the two operands.</p>
3124
3125<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3126<pre>
3127 &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]3128</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3129
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3130</div>
3131
3132<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3133<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3134</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3135
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3136<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3137
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3138<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3139<pre>
3140 &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]3141</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3142
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3143<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3144<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3145
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3146<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3147<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3148 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3149 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3150
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3151<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3152<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3153
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3154<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3155 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3156
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3157<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3158
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3159<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3160<pre>
3161 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3162</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3163
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3164</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3165
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3166<!-- _______________________________________________________________________ -->
3167<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3168</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3169
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3170<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3171
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3172<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3173<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3174 &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]3175 &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]3176</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3177
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3178<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3179<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3180
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3181<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3182<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3183 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3184 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3185
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3186<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3187<p>The value produced is the signed integer quotient of the two operands rounded
3188 towards zero.</p>
3189
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3190<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3191 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3192
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3193<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3194 undefined behavior; this is a rare case, but can occur, for example, by doing
3195 a 32-bit division of -2147483648 by -1.</p>
3196
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3197<p>If the <tt>exact</tt> keyword is present, the result value of the
3198 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3199 would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3200
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3201<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3202<pre>
3203 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3204</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3205
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3206</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3207
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3208<!-- _______________________________________________________________________ -->
3209<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3210Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3211
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3212<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3213
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3214<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3215<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3216 &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]3217</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3218
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3219<h5>Overview:</h5>
3220<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3221
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3222<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3223<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3224 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3225 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3226
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3227<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3228<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3229
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3230<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3231<pre>
3232 &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]3233</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3234
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3235</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3236
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3237<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3238<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3239</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3240
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3241<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3242
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3243<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3244<pre>
3245 &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]3246</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3247
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3248<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3249<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3250 division of its two arguments.</p>
3251
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3252<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3253<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3254 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3255 values. Both arguments must have identical types.</p>
3256
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3257<h5>Semantics:</h5>
3258<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3259 This instruction always performs an unsigned division to get the
3260 remainder.</p>
3261
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3262<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3263 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3264
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3265<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3266
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3267<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3268<pre>
3269 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3270</pre>
3271
3272</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3273
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3274<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3275<div class="doc_subsubsection">
3276 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3277</div>
3278
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3279<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3280
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3281<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3282<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3283 &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]3284</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3285
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3286<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3287<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3288 division of its two operands. This instruction can also take
3289 <a href="#t_vector">vector</a> versions of the values in which case the
3290 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3291
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3292<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3293<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3294 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3295 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3296
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3297<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3298<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3299 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3300 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3301 a value. For more information about the difference,
3302 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3303 Math Forum</a>. For a table of how this is implemented in various languages,
3304 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3305 Wikipedia: modulo operation</a>.</p>
3306
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3307<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3308 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3309
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3310<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3311 Overflow also leads to undefined behavior; this is a rare case, but can
3312 occur, for example, by taking the remainder of a 32-bit division of
3313 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3314 lets srem be implemented using instructions that return both the result of
3315 the division and the remainder.)</p>
3316
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3317<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3318<pre>
3319 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3320</pre>
3321
3322</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3323
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3324<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3325<div class="doc_subsubsection">
3326 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3327
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3328<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3329
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3330<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3331<pre>
3332 &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]3333</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3334
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3335<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3336<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3337 its two operands.</p>
3338
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3339<h5>Arguments:</h5>
3340<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3341 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3342 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3343
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3344<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3345<p>This instruction returns the <i>remainder</i> of a division. The remainder
3346 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3347
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3348<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3349<pre>
3350 &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]3351</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3352
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3353</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3354
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3355<!-- ======================================================================= -->
3356<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3357Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3358
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3359<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3360
3361<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3362 program. They are generally very efficient instructions and can commonly be
3363 strength reduced from other instructions. They require two operands of the
3364 same type, execute an operation on them, and produce a single value. The
3365 resulting value is the same type as its operands.</p>
3366
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3367</div>
3368
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3369<!-- _______________________________________________________________________ -->
3370<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3371Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3372
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3373<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3374
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3375<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3376<pre>
3377 &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]3378</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3379
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3380<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3381<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3382 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3383
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3384<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3385<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3386 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3387 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3388
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3389<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3390<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3391 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3392 is (statically or dynamically) negative or equal to or larger than the number
3393 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3394 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3395 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3396
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3397<h5>Example:</h5>
3398<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3399 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3400 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3401 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3402 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3403 &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]3404</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3405
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3406</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3407
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3408<!-- _______________________________________________________________________ -->
3409<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3410Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3411
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3412<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3413
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3414<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3415<pre>
3416 &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]3417</pre>
3418
3419<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3420<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3421 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3422
3423<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3424<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3425 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3426 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3427
3428<h5>Semantics:</h5>
3429<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3430 significant bits of the result will be filled with zero bits after the shift.
3431 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3432 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3433 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3434 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3435
3436<h5>Example:</h5>
3437<pre>
3438 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3439 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3440 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3441 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3442 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3443 &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]3444</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3445
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3446</div>
3447
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3448<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3449<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3450Instruction</a> </div>
3451<div class="doc_text">
3452
3453<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3454<pre>
3455 &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]3456</pre>
3457
3458<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3459<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3460 operand shifted to the right a specified number of bits with sign
3461 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3462
3463<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3464<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3465 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3466 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3467
3468<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3469<p>This instruction always performs an arithmetic shift right operation, The
3470 most significant bits of the result will be filled with the sign bit
3471 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3472 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3473 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3474 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3475
3476<h5>Example:</h5>
3477<pre>
3478 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3479 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3480 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3481 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3482 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3483 &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]3484</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3485
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3486</div>
3487
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3488<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3489<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3490Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3491
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3492<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3493
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3494<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3495<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3496 &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]3497</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3498
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3499<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3500<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3501 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3502
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3503<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3504<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3505 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3506 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3507
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3508<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3509<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3510
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3511<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3512 <tbody>
3513 <tr>
3514 <td>In0</td>
3515 <td>In1</td>
3516 <td>Out</td>
3517 </tr>
3518 <tr>
3519 <td>0</td>
3520 <td>0</td>
3521 <td>0</td>
3522 </tr>
3523 <tr>
3524 <td>0</td>
3525 <td>1</td>
3526 <td>0</td>
3527 </tr>
3528 <tr>
3529 <td>1</td>
3530 <td>0</td>
3531 <td>0</td>
3532 </tr>
3533 <tr>
3534 <td>1</td>
3535 <td>1</td>
3536 <td>1</td>
3537 </tr>
3538 </tbody>
3539</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3540
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3541<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3542<pre>
3543 &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]3544 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3545 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3546</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3547</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3548<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3549<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3550
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3551<div class="doc_text">
3552
3553<h5>Syntax:</h5>
3554<pre>
3555 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3556</pre>
3557
3558<h5>Overview:</h5>
3559<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3560 two operands.</p>
3561
3562<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3563<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3564 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3565 values. Both arguments must have identical types.</p>
3566
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3567<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3568<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3569
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3570<table border="1" cellspacing="0" cellpadding="4">
3571 <tbody>
3572 <tr>
3573 <td>In0</td>
3574 <td>In1</td>
3575 <td>Out</td>
3576 </tr>
3577 <tr>
3578 <td>0</td>
3579 <td>0</td>
3580 <td>0</td>
3581 </tr>
3582 <tr>
3583 <td>0</td>
3584 <td>1</td>
3585 <td>1</td>
3586 </tr>
3587 <tr>
3588 <td>1</td>
3589 <td>0</td>
3590 <td>1</td>
3591 </tr>
3592 <tr>
3593 <td>1</td>
3594 <td>1</td>
3595 <td>1</td>
3596 </tr>
3597 </tbody>
3598</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3599
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3600<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3601<pre>
3602 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3603 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3604 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3605</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3606
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3607</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3608
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3609<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3610<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3611Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3612
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3613<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3614
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3615<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3616<pre>
3617 &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]3618</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3619
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3620<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3621<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3622 its two operands. The <tt>xor</tt> is used to implement the "one's
3623 complement" operation, which is the "~" operator in C.</p>
3624
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3625<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3626<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3627 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3628 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3629
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3630<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3631<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3632
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3633<table border="1" cellspacing="0" cellpadding="4">
3634 <tbody>
3635 <tr>
3636 <td>In0</td>
3637 <td>In1</td>
3638 <td>Out</td>
3639 </tr>
3640 <tr>
3641 <td>0</td>
3642 <td>0</td>
3643 <td>0</td>
3644 </tr>
3645 <tr>
3646 <td>0</td>
3647 <td>1</td>
3648 <td>1</td>
3649 </tr>
3650 <tr>
3651 <td>1</td>
3652 <td>0</td>
3653 <td>1</td>
3654 </tr>
3655 <tr>
3656 <td>1</td>
3657 <td>1</td>
3658 <td>0</td>
3659 </tr>
3660 </tbody>
3661</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3662
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3663<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3664<pre>
3665 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3666 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3667 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3668 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3669</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3670
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3671</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3672
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3673<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3674<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3675 <a name="vectorops">Vector Operations</a>
3676</div>
3677
3678<div class="doc_text">
3679
3680<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3681 target-independent manner. These instructions cover the element-access and
3682 vector-specific operations needed to process vectors effectively. While LLVM
3683 does directly support these vector operations, many sophisticated algorithms
3684 will want to use target-specific intrinsics to take full advantage of a
3685 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3686
3687</div>
3688
3689<!-- _______________________________________________________________________ -->
3690<div class="doc_subsubsection">
3691 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3692</div>
3693
3694<div class="doc_text">
3695
3696<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3697<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3698 &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]3699</pre>
3700
3701<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3702<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3703 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3704
3705
3706<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3707<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3708 of <a href="#t_vector">vector</a> type. The second operand is an index
3709 indicating the position from which to extract the element. The index may be
3710 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3711
3712<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3713<p>The result is a scalar of the same type as the element type of
3714 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3715 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3716 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3717
3718<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3719<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3720 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3721</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3722
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3723</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3724
3725<!-- _______________________________________________________________________ -->
3726<div class="doc_subsubsection">
3727 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3728</div>
3729
3730<div class="doc_text">
3731
3732<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3733<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]3734 &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]3735</pre>
3736
3737<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3738<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3739 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +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>insertelement</tt>' instruction is a value
3743 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3744 whose type must equal the element type of the first operand. The third
3745 operand is an index indicating the position at which to insert the value.
3746 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3747
3748<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3749<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3750 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3751 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3752 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3753
3754<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3755<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3756 &lt;result&gt; = 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]3757</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3758
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3759</div>
3760
3761<!-- _______________________________________________________________________ -->
3762<div class="doc_subsubsection">
3763 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3764</div>
3765
3766<div class="doc_text">
3767
3768<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3769<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]3770 &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]3771</pre>
3772
3773<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3774<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3775 from two input vectors, returning a vector with the same element type as the
3776 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3777
3778<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3779<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3780 with types that match each other. The third argument is a shuffle mask whose
3781 element type is always 'i32'. The result of the instruction is a vector
3782 whose length is the same as the shuffle mask and whose element type is the
3783 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3784
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3785<p>The shuffle mask operand is required to be a constant vector with either
3786 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3787
3788<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3789<p>The elements of the two input vectors are numbered from left to right across
3790 both of the vectors. The shuffle mask operand specifies, for each element of
3791 the result vector, which element of the two input vectors the result element
3792 gets. The element selector may be undef (meaning "don't care") and the
3793 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3794
3795<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3796<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3797 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3798 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3799 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3800 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3801 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]3802 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3803 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]3804 &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]3805</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3806
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3807</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]3808
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3809<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3810<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3811 <a name="aggregateops">Aggregate Operations</a>
3812</div>
3813
3814<div class="doc_text">
3815
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3816<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3817
3818</div>
3819
3820<!-- _______________________________________________________________________ -->
3821<div class="doc_subsubsection">
3822 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3823</div>
3824
3825<div class="doc_text">
3826
3827<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3828<pre>
3829 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3830</pre>
3831
3832<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3833<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3834 or array element from an aggregate value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3835
3836<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3837<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3838 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3839 operands are constant indices to specify which value to extract in a similar
3840 manner as indices in a
3841 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3842
3843<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3844<p>The result is the value at the position in the aggregate specified by the
3845 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3846
3847<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3848<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3849 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3850</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3851
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3852</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3853
3854<!-- _______________________________________________________________________ -->
3855<div class="doc_subsubsection">
3856 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3857</div>
3858
3859<div class="doc_text">
3860
3861<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3862<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame^]3863 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt; <i>; yields &lt;aggregate type&gt;</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3864</pre>
3865
3866<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3867<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3868 array element in an aggregate.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3869
3870
3871<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3872<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3873 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3874 second operand is a first-class value to insert. The following operands are
3875 constant indices indicating the position at which to insert the value in a
3876 similar manner as indices in a
3877 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3878 value to insert must have the same type as the value identified by the
3879 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3880
3881<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3882<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3883 that of <tt>val</tt> except that the value at the position specified by the
3884 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3885
3886<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3887<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame^]3888 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
3889 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3890</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3891
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3892</div>
3893
3894
3895<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3896<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]3897 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]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
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3902<p>A key design point of an SSA-based representation is how it represents
3903 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]3904 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3905 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3906
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3907</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3908
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3909<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3910<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3911 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3912</div>
3913
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3914<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3915
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3916<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3917<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3918 &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]3919</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3920
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3921<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3922<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3923 currently executing function, to be automatically released when this function
3924 returns to its caller. The object is always allocated in the generic address
3925 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3926
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3927<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3928<p>The '<tt>alloca</tt>' instruction
3929 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3930 runtime stack, returning a pointer of the appropriate type to the program.
3931 If "NumElements" is specified, it is the number of elements allocated,
3932 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3933 specified, the value result of the allocation is guaranteed to be aligned to
3934 at least that boundary. If not specified, or if zero, the target can choose
3935 to align the allocation on any convenient boundary compatible with the
3936 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3937
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3938<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3939
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3940<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]3941<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3942 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3943 memory is automatically released when the function returns. The
3944 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3945 variables that must have an address available. When the function returns
3946 (either with the <tt><a href="#i_ret">ret</a></tt>
3947 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3948 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3949
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3950<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3951<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]3952 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3953 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3954 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3955 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3956</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3957
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3958</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3959
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3960<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3961<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3962Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3963
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3964<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3965
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3966<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3967<pre>
3968 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3969 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3970</pre>
3971
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3972<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3973<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3974
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3975<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3976<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3977 from which to load. The pointer must point to
3978 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3979 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3980 number or order of execution of this <tt>load</tt> with other
3981 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3982 instructions. </p>
3983
3984<p>The optional constant "align" argument specifies the alignment of the
3985 operation (that is, the alignment of the memory address). A value of 0 or an
3986 omitted "align" argument means that the operation has the preferential
3987 alignment for the target. It is the responsibility of the code emitter to
3988 ensure that the alignment information is correct. Overestimating the
3989 alignment results in an undefined behavior. Underestimating the alignment may
3990 produce less efficient code. An alignment of 1 is always safe.</p>
3991
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3992<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3993<p>The location of memory pointed to is loaded. If the value being loaded is of
3994 scalar type then the number of bytes read does not exceed the minimum number
3995 of bytes needed to hold all bits of the type. For example, loading an
3996 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3997 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3998 is undefined if the value was not originally written using a store of the
3999 same type.</p>
4000
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4001<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4002<pre>
4003 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4004 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4005 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4006</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4007
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4008</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4009
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4010<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4011<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4012Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4013
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4014<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4015
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4016<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4017<pre>
4018 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]4019 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]4020</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4021
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4022<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4023<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4024
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4025<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4026<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4027 and an address at which to store it. The type of the
4028 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4029 the <a href="#t_firstclass">first class</a> type of the
4030 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4031 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4032 or order of execution of this <tt>store</tt> with other
4033 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4034 instructions.</p>
4035
4036<p>The optional constant "align" argument specifies the alignment of the
4037 operation (that is, the alignment of the memory address). A value of 0 or an
4038 omitted "align" argument means that the operation has the preferential
4039 alignment for the target. It is the responsibility of the code emitter to
4040 ensure that the alignment information is correct. Overestimating the
4041 alignment results in an undefined behavior. Underestimating the alignment may
4042 produce less efficient code. An alignment of 1 is always safe.</p>
4043
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4044<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4045<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4046 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4047 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4048 does not exceed the minimum number of bytes needed to hold all bits of the
4049 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4050 writing a value of a type like <tt>i20</tt> with a size that is not an
4051 integral number of bytes, it is unspecified what happens to the extra bits
4052 that do not belong to the type, but they will typically be overwritten.</p>
4053
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4054<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4055<pre>
4056 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4057 store i32 3, i32* %ptr <i>; yields {void}</i>
4058 %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]4059</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4060
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4061</div>
4062
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4063<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4064<div class="doc_subsubsection">
4065 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4066</div>
4067
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4068<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4069
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4070<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4071<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4072 &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]4073 &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]4074</pre>
4075
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4076<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4077<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4078 subelement of an aggregate data structure. It performs address calculation
4079 only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4080
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4081<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4082<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4083 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4084 elements of the aggregate object are indexed. The interpretation of each
4085 index is dependent on the type being indexed into. The first index always
4086 indexes the pointer value given as the first argument, the second index
4087 indexes a value of the type pointed to (not necessarily the value directly
4088 pointed to, since the first index can be non-zero), etc. The first type
4089 indexed into must be a pointer value, subsequent types can be arrays, vectors
4090 and structs. Note that subsequent types being indexed into can never be
4091 pointers, since that would require loading the pointer before continuing
4092 calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4093
4094<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]4095 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4096 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4097 vector, integers of any width are allowed, and they are not required to be
4098 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4099
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4100<p>For example, let's consider a C code fragment and how it gets compiled to
4101 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4102
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4103<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4104<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4105struct RT {
4106 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4107 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4108 char C;
4109};
4110struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4111 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4112 double Y;
4113 struct RT Z;
4114};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4115
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4116int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4117 return &amp;s[1].Z.B[5][13];
4118}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4119</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4120</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4121
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4122<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4123
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4124<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4125<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4126%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4127%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4128
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4129define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4130entry:
4131 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4132 ret i32* %reg
4133}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4134</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4135</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4136
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4137<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4138<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]4139 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4140 }</tt>' type, a structure. The second index indexes into the third element
4141 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4142 i8 }</tt>' type, another structure. The third index indexes into the second
4143 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4144 array. The two dimensions of the array are subscripted into, yielding an
4145 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4146 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4147
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4148<p>Note that it is perfectly legal to index partially through a structure,
4149 returning a pointer to an inner element. Because of this, the LLVM code for
4150 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4151
4152<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4153 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4154 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4155 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4156 %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]4157 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4158 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4159 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4160 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4161</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4162
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4163<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4164 <tt>getelementptr</tt> is undefined if the base pointer is not an
4165 <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]4166 that would be formed by successive addition of the offsets implied by the
4167 indices to the base address with infinitely precise arithmetic are not an
4168 <i>in bounds</i> address of that allocated object.
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4169 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohman2de532c2009-08-20 17:08:17 +0000[diff] [blame]4170 that point into the object, plus the address one byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4171
4172<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4173 the base address with silently-wrapping two's complement arithmetic, and
4174 the result value of the <tt>getelementptr</tt> may be outside the object
4175 pointed to by the base pointer. The result value may not necessarily be
4176 used to access memory though, even if it happens to point into allocated
4177 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4178 section for more information.</p>
4179
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4180<p>The getelementptr instruction is often confusing. For some more insight into
4181 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4182
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4183<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4184<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4185 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4186 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4187 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4188 %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]4189 <i>; yields i8*:eptr</i>
4190 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4191 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4192 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4193</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4194
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4195</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4196
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4197<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4198<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4199</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4200
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4201<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4202
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4203<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4204 which all take a single operand and a type. They perform various bit
4205 conversions on the operand.</p>
4206
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4207</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4208
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4209<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4210<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4211 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4212</div>
4213<div class="doc_text">
4214
4215<h5>Syntax:</h5>
4216<pre>
4217 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4218</pre>
4219
4220<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4221<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4222 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4223
4224<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4225<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4226 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4227 size and type of the result, which must be
4228 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4229 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4230 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4231
4232<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4233<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4234 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4235 source size must be larger than the destination size, <tt>trunc</tt> cannot
4236 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4237
4238<h5>Example:</h5>
4239<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4240 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4241 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4242 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4243</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4244
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4245</div>
4246
4247<!-- _______________________________________________________________________ -->
4248<div class="doc_subsubsection">
4249 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4250</div>
4251<div class="doc_text">
4252
4253<h5>Syntax:</h5>
4254<pre>
4255 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4256</pre>
4257
4258<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4259<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4260 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4261
4262
4263<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4264<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]4265 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4266 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4267 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4268 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4269
4270<h5>Semantics:</h5>
4271<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]4272 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4273
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4274<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]4275
4276<h5>Example:</h5>
4277<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4278 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4279 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4280</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4281
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4282</div>
4283
4284<!-- _______________________________________________________________________ -->
4285<div class="doc_subsubsection">
4286 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4287</div>
4288<div class="doc_text">
4289
4290<h5>Syntax:</h5>
4291<pre>
4292 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4293</pre>
4294
4295<h5>Overview:</h5>
4296<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4297
4298<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4299<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4300 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4301 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4302 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4303 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4304
4305<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4306<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4307 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4308 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4309
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4310<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]4311
4312<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4313<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4314 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4315 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4316</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4317
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4318</div>
4319
4320<!-- _______________________________________________________________________ -->
4321<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4322 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4323</div>
4324
4325<div class="doc_text">
4326
4327<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4328<pre>
4329 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4330</pre>
4331
4332<h5>Overview:</h5>
4333<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4334 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4335
4336<h5>Arguments:</h5>
4337<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4338 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4339 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4340 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4341 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4342
4343<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4344<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4345 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4346 <a href="#t_floating">floating point</a> type. If the value cannot fit
4347 within the destination type, <tt>ty2</tt>, then the results are
4348 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4349
4350<h5>Example:</h5>
4351<pre>
4352 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4353 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4354</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4355
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4356</div>
4357
4358<!-- _______________________________________________________________________ -->
4359<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4360 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4361</div>
4362<div class="doc_text">
4363
4364<h5>Syntax:</h5>
4365<pre>
4366 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4367</pre>
4368
4369<h5>Overview:</h5>
4370<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]4371 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4372
4373<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4374<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4375 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4376 a <a href="#t_floating">floating point</a> type to cast it to. The source
4377 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4378
4379<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4380<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4381 <a href="#t_floating">floating point</a> type to a larger
4382 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4383 used to make a <i>no-op cast</i> because it always changes bits. Use
4384 <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]4385
4386<h5>Example:</h5>
4387<pre>
4388 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4389 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4390</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4391
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4392</div>
4393
4394<!-- _______________________________________________________________________ -->
4395<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4396 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4397</div>
4398<div class="doc_text">
4399
4400<h5>Syntax:</h5>
4401<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4402 &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]4403</pre>
4404
4405<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4406<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4407 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4408
4409<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4410<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4411 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4412 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4413 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4414 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4415
4416<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4417<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4418 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4419 towards zero) unsigned integer value. If the value cannot fit
4420 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4421
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4422<h5>Example:</h5>
4423<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4424 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4425 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4426 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4427</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4428
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4429</div>
4430
4431<!-- _______________________________________________________________________ -->
4432<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4433 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4434</div>
4435<div class="doc_text">
4436
4437<h5>Syntax:</h5>
4438<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4439 &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]4440</pre>
4441
4442<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4443<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4444 <a href="#t_floating">floating point</a> <tt>value</tt> to
4445 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4446
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4447<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4448<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4449 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4450 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4451 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4452 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4453
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4454<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4455<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4456 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4457 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4458 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4459
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4460<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4461<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4462 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4463 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4464 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4465</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4466
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4467</div>
4468
4469<!-- _______________________________________________________________________ -->
4470<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4471 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4472</div>
4473<div class="doc_text">
4474
4475<h5>Syntax:</h5>
4476<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4477 &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]4478</pre>
4479
4480<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4481<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4482 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4483
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4484<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4485<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]4486 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4487 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4488 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4489 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4490
4491<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4492<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4493 integer quantity and converts it to the corresponding floating point
4494 value. If the value cannot fit in the floating point value, the results are
4495 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4496
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4497<h5>Example:</h5>
4498<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4499 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4500 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4501</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4502
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4503</div>
4504
4505<!-- _______________________________________________________________________ -->
4506<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4507 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4508</div>
4509<div class="doc_text">
4510
4511<h5>Syntax:</h5>
4512<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4513 &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]4514</pre>
4515
4516<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4517<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4518 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4519
4520<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4521<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]4522 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4523 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4524 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4525 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4526
4527<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4528<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4529 quantity and converts it to the corresponding floating point value. If the
4530 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4531
4532<h5>Example:</h5>
4533<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4534 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4535 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4536</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4537
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4538</div>
4539
4540<!-- _______________________________________________________________________ -->
4541<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4542 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4543</div>
4544<div class="doc_text">
4545
4546<h5>Syntax:</h5>
4547<pre>
4548 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4549</pre>
4550
4551<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4552<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4553 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4554
4555<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4556<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4557 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4558 <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]4559
4560<h5>Semantics:</h5>
4561<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4562 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4563 truncating or zero extending that value to the size of the integer type. If
4564 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4565 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4566 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4567 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4568
4569<h5>Example:</h5>
4570<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4571 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4572 %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]4573</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4574
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4575</div>
4576
4577<!-- _______________________________________________________________________ -->
4578<div class="doc_subsubsection">
4579 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4580</div>
4581<div class="doc_text">
4582
4583<h5>Syntax:</h5>
4584<pre>
4585 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4586</pre>
4587
4588<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4589<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4590 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4591
4592<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4593<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4594 value to cast, and a type to cast it to, which must be a
4595 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4596
4597<h5>Semantics:</h5>
4598<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4599 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4600 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4601 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4602 than the size of a pointer then a zero extension is done. If they are the
4603 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4604
4605<h5>Example:</h5>
4606<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4607 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4608 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4609 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4610</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4611
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4612</div>
4613
4614<!-- _______________________________________________________________________ -->
4615<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4616 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4617</div>
4618<div class="doc_text">
4619
4620<h5>Syntax:</h5>
4621<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4622 &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]4623</pre>
4624
4625<h5>Overview:</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> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4628
4629<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4630<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4631 non-aggregate first class value, and a type to cast it to, which must also be
4632 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4633 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4634 identical. If the source type is a pointer, the destination type must also be
4635 a pointer. This instruction supports bitwise conversion of vectors to
4636 integers and to vectors of other types (as long as they have the same
4637 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4638
4639<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4640<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4641 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4642 this conversion. The conversion is done as if the <tt>value</tt> had been
4643 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4644 be converted to other pointer types with this instruction. To convert
4645 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4646 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4647
4648<h5>Example:</h5>
4649<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4650 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4651 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4652 %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]4653</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4654
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4655</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4656
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4657<!-- ======================================================================= -->
4658<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4659
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4660<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4661
4662<p>The instructions in this category are the "miscellaneous" instructions, which
4663 defy better classification.</p>
4664
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4665</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4666
4667<!-- _______________________________________________________________________ -->
4668<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4669</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4670
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4671<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4672
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4673<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4674<pre>
4675 &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]4676</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4677
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4678<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4679<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4680 boolean values based on comparison of its two integer, integer vector, or
4681 pointer operands.</p>
4682
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4683<h5>Arguments:</h5>
4684<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4685 the condition code indicating the kind of comparison to perform. It is not a
4686 value, just a keyword. The possible condition code are:</p>
4687
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4688<ol>
4689 <li><tt>eq</tt>: equal</li>
4690 <li><tt>ne</tt>: not equal </li>
4691 <li><tt>ugt</tt>: unsigned greater than</li>
4692 <li><tt>uge</tt>: unsigned greater or equal</li>
4693 <li><tt>ult</tt>: unsigned less than</li>
4694 <li><tt>ule</tt>: unsigned less or equal</li>
4695 <li><tt>sgt</tt>: signed greater than</li>
4696 <li><tt>sge</tt>: signed greater or equal</li>
4697 <li><tt>slt</tt>: signed less than</li>
4698 <li><tt>sle</tt>: signed less or equal</li>
4699</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4700
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]4701<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4702 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4703 typed. They must also be identical types.</p>
4704
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4705<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4706<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4707 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4708 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4709 result, as follows:</p>
4710
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4711<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4712 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4713 <tt>false</tt> otherwise. No sign interpretation is necessary or
4714 performed.</li>
4715
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4716 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4717 <tt>false</tt> otherwise. No sign interpretation is necessary or
4718 performed.</li>
4719
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4720 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4721 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4722
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4723 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4724 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4725 to <tt>op2</tt>.</li>
4726
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4727 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4728 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4729
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4730 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4731 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4732
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4733 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4734 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4735
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4736 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4737 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4738 to <tt>op2</tt>.</li>
4739
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4740 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4741 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4742
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4743 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4744 <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]4745</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4746
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4747<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4748 values are compared as if they were integers.</p>
4749
4750<p>If the operands are integer vectors, then they are compared element by
4751 element. The result is an <tt>i1</tt> vector with the same number of elements
4752 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4753
4754<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4755<pre>
4756 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4757 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4758 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4759 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4760 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4761 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4762</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4763
4764<p>Note that the code generator does not yet support vector types with
4765 the <tt>icmp</tt> instruction.</p>
4766
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4767</div>
4768
4769<!-- _______________________________________________________________________ -->
4770<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4771</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4772
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4773<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4774
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4775<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4776<pre>
4777 &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]4778</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4779
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4780<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4781<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4782 values based on comparison of its operands.</p>
4783
4784<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4785(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4786
4787<p>If the operands are floating point vectors, then the result type is a vector
4788 of boolean with the same number of elements as the operands being
4789 compared.</p>
4790
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4791<h5>Arguments:</h5>
4792<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4793 the condition code indicating the kind of comparison to perform. It is not a
4794 value, just a keyword. The possible condition code are:</p>
4795
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4796<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4797 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4798 <li><tt>oeq</tt>: ordered and equal</li>
4799 <li><tt>ogt</tt>: ordered and greater than </li>
4800 <li><tt>oge</tt>: ordered and greater than or equal</li>
4801 <li><tt>olt</tt>: ordered and less than </li>
4802 <li><tt>ole</tt>: ordered and less than or equal</li>
4803 <li><tt>one</tt>: ordered and not equal</li>
4804 <li><tt>ord</tt>: ordered (no nans)</li>
4805 <li><tt>ueq</tt>: unordered or equal</li>
4806 <li><tt>ugt</tt>: unordered or greater than </li>
4807 <li><tt>uge</tt>: unordered or greater than or equal</li>
4808 <li><tt>ult</tt>: unordered or less than </li>
4809 <li><tt>ule</tt>: unordered or less than or equal</li>
4810 <li><tt>une</tt>: unordered or not equal</li>
4811 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4812 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4813</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4814
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4815<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4816 <i>unordered</i> means that either operand may be a QNAN.</p>
4817
4818<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4819 a <a href="#t_floating">floating point</a> type or
4820 a <a href="#t_vector">vector</a> of floating point type. They must have
4821 identical types.</p>
4822
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4823<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4824<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4825 according to the condition code given as <tt>cond</tt>. If the operands are
4826 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4827 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4828 follows:</p>
4829
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4830<ol>
4831 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4832
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4833 <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]4834 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4835
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4836 <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]4837 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4838
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4839 <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]4840 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4841
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4842 <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]4843 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4844
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4845 <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]4846 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4847
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4848 <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]4849 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4850
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4851 <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]4852
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4853 <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]4854 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4855
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4856 <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]4857 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4858
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4859 <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]4860 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4861
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4862 <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]4863 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4864
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4865 <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]4866 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4867
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4868 <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]4869 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4870
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4871 <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]4872
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4873 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4874</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4875
4876<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4877<pre>
4878 &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]4879 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4880 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4881 &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]4882</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4883
4884<p>Note that the code generator does not yet support vector types with
4885 the <tt>fcmp</tt> instruction.</p>
4886
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4887</div>
4888
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4889<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]4890<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4891 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4892</div>
4893
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4894<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4895
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4896<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4897<pre>
4898 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4899</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4900
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4901<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4902<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4903 SSA graph representing the function.</p>
4904
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4905<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4906<p>The type of the incoming values is specified with the first type field. After
4907 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4908 one pair for each predecessor basic block of the current block. Only values
4909 of <a href="#t_firstclass">first class</a> type may be used as the value
4910 arguments to the PHI node. Only labels may be used as the label
4911 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4912
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4913<p>There must be no non-phi instructions between the start of a basic block and
4914 the PHI instructions: i.e. PHI instructions must be first in a basic
4915 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4916
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4917<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4918 occur on the edge from the corresponding predecessor block to the current
4919 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4920 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]4921
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4922<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4923<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4924 specified by the pair corresponding to the predecessor basic block that
4925 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4926
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4927<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4928<pre>
4929Loop: ; Infinite loop that counts from 0 on up...
4930 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4931 %nextindvar = add i32 %indvar, 1
4932 br label %Loop
4933</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4934
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4935</div>
4936
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4937<!-- _______________________________________________________________________ -->
4938<div class="doc_subsubsection">
4939 <a name="i_select">'<tt>select</tt>' Instruction</a>
4940</div>
4941
4942<div class="doc_text">
4943
4944<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4945<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]4946 &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>
4947
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4948 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4949</pre>
4950
4951<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4952<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4953 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4954
4955
4956<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4957<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4958 values indicating the condition, and two values of the
4959 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4960 vectors and the condition is a scalar, then entire vectors are selected, not
4961 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4962
4963<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4964<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4965 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4966
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4967<p>If the condition is a vector of i1, then the value arguments must be vectors
4968 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4969
4970<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4971<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4972 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4973</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4974
4975<p>Note that the code generator does not yet support conditions
4976 with vector type.</p>
4977
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4978</div>
4979
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]4980<!-- _______________________________________________________________________ -->
4981<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4982 <a name="i_call">'<tt>call</tt>' Instruction</a>
4983</div>
4984
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4985<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4986
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4987<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4988<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]4989 &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]4990</pre>
4991
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4992<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4993<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4994
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4995<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4996<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4997
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4998<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]4999 <li>The optional "tail" marker indicates that the callee function does not
5000 access any allocas or varargs in the caller. Note that calls may be
5001 marked "tail" even if they do not occur before
5002 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5003 present, the function call is eligible for tail call optimization,
5004 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
5005 optimized into a jump</a>. As of this writing, the extra requirements for
5006 a call to actually be optimized are:
5007 <ul>
5008 <li>Caller and callee both have the calling
5009 convention <tt>fastcc</tt>.</li>
5010 <li>The call is in tail position (ret immediately follows call and ret
5011 uses value of call or is void).</li>
5012 <li>Option <tt>-tailcallopt</tt> is enabled,
5013 or <code>llvm::PerformTailCallOpt</code> is <code>true</code>.</li>
5014 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5015 constraints are met.</a></li>
5016 </ul>
5017 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5018
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5019 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5020 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5021 defaults to using C calling conventions. The calling convention of the
5022 call must match the calling convention of the target function, or else the
5023 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5024
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5025 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5026 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5027 '<tt>inreg</tt>' attributes are valid here.</li>
5028
5029 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5030 type of the return value. Functions that return no value are marked
5031 <tt><a href="#t_void">void</a></tt>.</li>
5032
5033 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5034 being invoked. The argument types must match the types implied by this
5035 signature. This type can be omitted if the function is not varargs and if
5036 the function type does not return a pointer to a function.</li>
5037
5038 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5039 be invoked. In most cases, this is a direct function invocation, but
5040 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5041 to function value.</li>
5042
5043 <li>'<tt>function args</tt>': argument list whose types match the function
5044 signature argument types. All arguments must be of
5045 <a href="#t_firstclass">first class</a> type. If the function signature
5046 indicates the function accepts a variable number of arguments, the extra
5047 arguments can be specified.</li>
5048
5049 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5050 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5051 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5052</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5053
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5054<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5055<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5056 a specified function, with its incoming arguments bound to the specified
5057 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5058 function, control flow continues with the instruction after the function
5059 call, and the return value of the function is bound to the result
5060 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5061
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5062<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5063<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5064 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5065 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5066 %X = tail call i32 @foo() <i>; yields i32</i>
5067 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5068 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5069
5070 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5071 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5072 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5073 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5074 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5075 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5076</pre>
5077
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5078<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5079standard C99 library as being the C99 library functions, and may perform
5080optimizations or generate code for them under that assumption. This is
5081something we'd like to change in the future to provide better support for
5082freestanding environments and non-C-based langauges.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5083
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5084</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5085
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5086<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5087<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5088 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5089</div>
5090
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5091<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5092
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5093<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5094<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5095 &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]5096</pre>
5097
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5098<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5099<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5100 the "variable argument" area of a function call. It is used to implement the
5101 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5102
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5103<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5104<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5105 argument. It returns a value of the specified argument type and increments
5106 the <tt>va_list</tt> to point to the next argument. The actual type
5107 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5108
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5109<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5110<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5111 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5112 to the next argument. For more information, see the variable argument
5113 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5114
5115<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]5116 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5117 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5118
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5119<p><tt>va_arg</tt> is an LLVM instruction instead of
5120 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5121 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5122
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5123<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5124<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5125
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5126<p>Note that the code generator does not yet fully support va_arg on many
5127 targets. Also, it does not currently support va_arg with aggregate types on
5128 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5129
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5130</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5131
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5132<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5133<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5134<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5135
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5136<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5137
5138<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5139 well known names and semantics and are required to follow certain
5140 restrictions. Overall, these intrinsics represent an extension mechanism for
5141 the LLVM language that does not require changing all of the transformations
5142 in LLVM when adding to the language (or the bitcode reader/writer, the
5143 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5144
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5145<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5146 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5147 begin with this prefix. Intrinsic functions must always be external
5148 functions: you cannot define the body of intrinsic functions. Intrinsic
5149 functions may only be used in call or invoke instructions: it is illegal to
5150 take the address of an intrinsic function. Additionally, because intrinsic
5151 functions are part of the LLVM language, it is required if any are added that
5152 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5153
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5154<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5155 family of functions that perform the same operation but on different data
5156 types. Because LLVM can represent over 8 million different integer types,
5157 overloading is used commonly to allow an intrinsic function to operate on any
5158 integer type. One or more of the argument types or the result type can be
5159 overloaded to accept any integer type. Argument types may also be defined as
5160 exactly matching a previous argument's type or the result type. This allows
5161 an intrinsic function which accepts multiple arguments, but needs all of them
5162 to be of the same type, to only be overloaded with respect to a single
5163 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5164
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5165<p>Overloaded intrinsics will have the names of its overloaded argument types
5166 encoded into its function name, each preceded by a period. Only those types
5167 which are overloaded result in a name suffix. Arguments whose type is matched
5168 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5169 can take an integer of any width and returns an integer of exactly the same
5170 integer width. This leads to a family of functions such as
5171 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5172 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5173 suffix is required. Because the argument's type is matched against the return
5174 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5175
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5176<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5177 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5178
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5179</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5180
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5181<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5182<div class="doc_subsection">
5183 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5184</div>
5185
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5186<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5187
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5188<p>Variable argument support is defined in LLVM with
5189 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5190 intrinsic functions. These functions are related to the similarly named
5191 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5192
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5193<p>All of these functions operate on arguments that use a target-specific value
5194 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5195 not define what this type is, so all transformations should be prepared to
5196 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5197
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5198<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]5199 instruction and the variable argument handling intrinsic functions are
5200 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5201
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5202<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5203<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5204define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5205 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5206 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5207 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5208 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5209
5210 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5211 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5212
5213 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5214 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5215 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5216 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5217 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5218
5219 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5220 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5221 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5222}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5223
5224declare void @llvm.va_start(i8*)
5225declare void @llvm.va_copy(i8*, i8*)
5226declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5227</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5228</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5229
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5230</div>
5231
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5232<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5233<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5234 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5235</div>
5236
5237
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5238<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5239
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5240<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5241<pre>
5242 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5243</pre>
5244
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5245<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5246<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5247 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]5248
5249<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5250<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]5251
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5252<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5253<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]5254 macro available in C. In a target-dependent way, it initializes
5255 the <tt>va_list</tt> element to which the argument points, so that the next
5256 call to <tt>va_arg</tt> will produce the first variable argument passed to
5257 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5258 need to know the last argument of the function as the compiler can figure
5259 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5260
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5261</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5262
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5263<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5264<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5265 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5266</div>
5267
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5268<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5269
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5270<h5>Syntax:</h5>
5271<pre>
5272 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5273</pre>
5274
5275<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5276<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5277 which has been initialized previously
5278 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5279 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5280
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5281<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5282<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]5283
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5284<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5285<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]5286 macro available in C. In a target-dependent way, it destroys
5287 the <tt>va_list</tt> element to which the argument points. Calls
5288 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5289 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5290 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5291
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5292</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5293
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5294<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5295<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5296 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5297</div>
5298
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5299<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5300
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5301<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5302<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5303 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5304</pre>
5305
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5306<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5307<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5308 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5309
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5310<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5311<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]5312 The second argument is a pointer to a <tt>va_list</tt> element to copy
5313 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5314
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5315<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5316<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]5317 macro available in C. In a target-dependent way, it copies the
5318 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5319 element. This intrinsic is necessary because
5320 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5321 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5322
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5323</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5324
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5325<!-- ======================================================================= -->
5326<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5327 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5328</div>
5329
5330<div class="doc_text">
5331
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5332<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5333Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5334intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5335roots on the stack</a>, as well as garbage collector implementations that
5336require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5337barriers. Front-ends for type-safe garbage collected languages should generate
5338these intrinsics to make use of the LLVM garbage collectors. For more details,
5339see <a href="GarbageCollection.html">Accurate Garbage Collection with
5340LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5341
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5342<p>The garbage collection intrinsics only operate on objects in the generic
5343 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5344
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5345</div>
5346
5347<!-- _______________________________________________________________________ -->
5348<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5349 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5350</div>
5351
5352<div class="doc_text">
5353
5354<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5355<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5356 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5357</pre>
5358
5359<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5360<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]5361 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5362
5363<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5364<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5365 root pointer. The second pointer (which must be either a constant or a
5366 global value address) contains the meta-data to be associated with the
5367 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5368
5369<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5370<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]5371 location. At compile-time, the code generator generates information to allow
5372 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5373 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5374 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5375
5376</div>
5377
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5378<!-- _______________________________________________________________________ -->
5379<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5380 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5381</div>
5382
5383<div class="doc_text">
5384
5385<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5386<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5387 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5388</pre>
5389
5390<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5391<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5392 locations, allowing garbage collector implementations that require read
5393 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5394
5395<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5396<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]5397 allocated from the garbage collector. The first object is a pointer to the
5398 start of the referenced object, if needed by the language runtime (otherwise
5399 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5400
5401<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5402<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5403 instruction, but may be replaced with substantially more complex code by the
5404 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5405 may only be used in a function which <a href="#gc">specifies a GC
5406 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5407
5408</div>
5409
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5410<!-- _______________________________________________________________________ -->
5411<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5412 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5413</div>
5414
5415<div class="doc_text">
5416
5417<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5418<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5419 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5420</pre>
5421
5422<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5423<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5424 locations, allowing garbage collector implementations that require write
5425 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5426
5427<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5428<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]5429 object to store it to, and the third is the address of the field of Obj to
5430 store to. If the runtime does not require a pointer to the object, Obj may
5431 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5432
5433<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5434<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5435 instruction, but may be replaced with substantially more complex code by the
5436 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5437 may only be used in a function which <a href="#gc">specifies a GC
5438 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5439
5440</div>
5441
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5442<!-- ======================================================================= -->
5443<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5444 <a name="int_codegen">Code Generator Intrinsics</a>
5445</div>
5446
5447<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5448
5449<p>These intrinsics are provided by LLVM to expose special features that may
5450 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5451
5452</div>
5453
5454<!-- _______________________________________________________________________ -->
5455<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5456 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5457</div>
5458
5459<div class="doc_text">
5460
5461<h5>Syntax:</h5>
5462<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5463 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5464</pre>
5465
5466<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5467<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5468 target-specific value indicating the return address of the current function
5469 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5470
5471<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5472<p>The argument to this intrinsic indicates which function to return the address
5473 for. Zero indicates the calling function, one indicates its caller, etc.
5474 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5475
5476<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5477<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5478 indicating the return address of the specified call frame, or zero if it
5479 cannot be identified. The value returned by this intrinsic is likely to be
5480 incorrect or 0 for arguments other than zero, so it should only be used for
5481 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5482
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5483<p>Note that calling this intrinsic does not prevent function inlining or other
5484 aggressive transformations, so the value returned may not be that of the
5485 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5486
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5487</div>
5488
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5489<!-- _______________________________________________________________________ -->
5490<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5491 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5492</div>
5493
5494<div class="doc_text">
5495
5496<h5>Syntax:</h5>
5497<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5498 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5499</pre>
5500
5501<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5502<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5503 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5504
5505<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5506<p>The argument to this intrinsic indicates which function to return the frame
5507 pointer for. Zero indicates the calling function, one indicates its caller,
5508 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5509
5510<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5511<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5512 indicating the frame address of the specified call frame, or zero if it
5513 cannot be identified. The value returned by this intrinsic is likely to be
5514 incorrect or 0 for arguments other than zero, so it should only be used for
5515 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5516
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5517<p>Note that calling this intrinsic does not prevent function inlining or other
5518 aggressive transformations, so the value returned may not be that of the
5519 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5520
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5521</div>
5522
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5523<!-- _______________________________________________________________________ -->
5524<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5525 <a name="int_stacksave">'<tt>llvm.stacksave</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>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5532 declare i8 *@llvm.stacksave()
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.stacksave</tt>' intrinsic is used to remember the current state
5537 of the function stack, for use
5538 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5539 useful for implementing language features like scoped automatic variable
5540 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>This intrinsic returns a opaque pointer value that can be passed
5544 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5545 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5546 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5547 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5548 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5549 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5550
5551</div>
5552
5553<!-- _______________________________________________________________________ -->
5554<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5555 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5556</div>
5557
5558<div class="doc_text">
5559
5560<h5>Syntax:</h5>
5561<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5562 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5563</pre>
5564
5565<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5566<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5567 the function stack to the state it was in when the
5568 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5569 executed. This is useful for implementing language features like scoped
5570 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5571
5572<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5573<p>See the description
5574 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5575
5576</div>
5577
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5578<!-- _______________________________________________________________________ -->
5579<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5580 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5581</div>
5582
5583<div class="doc_text">
5584
5585<h5>Syntax:</h5>
5586<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5587 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]5588</pre>
5589
5590<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5591<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5592 insert a prefetch instruction if supported; otherwise, it is a noop.
5593 Prefetches have no effect on the behavior of the program but can change its
5594 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5595
5596<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5597<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5598 specifier determining if the fetch should be for a read (0) or write (1),
5599 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5600 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5601 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5602
5603<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5604<p>This intrinsic does not modify the behavior of the program. In particular,
5605 prefetches cannot trap and do not produce a value. On targets that support
5606 this intrinsic, the prefetch can provide hints to the processor cache for
5607 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5608
5609</div>
5610
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5611<!-- _______________________________________________________________________ -->
5612<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5613 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5614</div>
5615
5616<div class="doc_text">
5617
5618<h5>Syntax:</h5>
5619<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5620 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5621</pre>
5622
5623<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5624<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5625 Counter (PC) in a region of code to simulators and other tools. The method
5626 is target specific, but it is expected that the marker will use exported
5627 symbols to transmit the PC of the marker. The marker makes no guarantees
5628 that it will remain with any specific instruction after optimizations. It is
5629 possible that the presence of a marker will inhibit optimizations. The
5630 intended use is to be inserted after optimizations to allow correlations of
5631 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5632
5633<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5634<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5635
5636<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5637<p>This intrinsic does not modify the behavior of the program. Backends that do
5638 not support this intrinisic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5639
5640</div>
5641
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5642<!-- _______________________________________________________________________ -->
5643<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5644 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5645</div>
5646
5647<div class="doc_text">
5648
5649<h5>Syntax:</h5>
5650<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5651 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5652</pre>
5653
5654<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5655<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5656 counter register (or similar low latency, high accuracy clocks) on those
5657 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5658 should map to RPCC. As the backing counters overflow quickly (on the order
5659 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5660
5661<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5662<p>When directly supported, reading the cycle counter should not modify any
5663 memory. Implementations are allowed to either return a application specific
5664 value or a system wide value. On backends without support, this is lowered
5665 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5666
5667</div>
5668
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5669<!-- ======================================================================= -->
5670<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5671 <a name="int_libc">Standard C Library Intrinsics</a>
5672</div>
5673
5674<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5675
5676<p>LLVM provides intrinsics for a few important standard C library functions.
5677 These intrinsics allow source-language front-ends to pass information about
5678 the alignment of the pointer arguments to the code generator, providing
5679 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5680
5681</div>
5682
5683<!-- _______________________________________________________________________ -->
5684<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5685 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5686</div>
5687
5688<div class="doc_text">
5689
5690<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5691<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5692 integer bit width. Not all targets support all bit widths however.</p>
5693
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5694<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5695 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5696 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5697 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5698 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5699 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5700 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5701 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5702 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5703</pre>
5704
5705<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5706<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5707 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5708
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5709<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5710 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5711
5712<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5713<p>The first argument is a pointer to the destination, the second is a pointer
5714 to the source. The third argument is an integer argument specifying the
5715 number of bytes to copy, and the fourth argument is the alignment of the
5716 source and destination locations.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5717
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5718<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5719 then the caller guarantees that both the source and destination pointers are
5720 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5721
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5722<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5723<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5724 source location to the destination location, which are not allowed to
5725 overlap. It copies "len" bytes of memory over. If the argument is known to
5726 be aligned to some boundary, this can be specified as the fourth argument,
5727 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5728
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5729</div>
5730
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5731<!-- _______________________________________________________________________ -->
5732<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5733 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5734</div>
5735
5736<div class="doc_text">
5737
5738<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5739<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]5740 width. Not all targets support all bit widths however.</p>
5741
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5742<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5743 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5744 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5745 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5746 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5747 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5748 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5749 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5750 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5751</pre>
5752
5753<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5754<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5755 source location to the destination location. It is similar to the
5756 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5757 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5758
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5759<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5760 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5761
5762<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5763<p>The first argument is a pointer to the destination, the second is a pointer
5764 to the source. The third argument is an integer argument specifying the
5765 number of bytes to copy, and the fourth argument is the alignment of the
5766 source and destination locations.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5767
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5768<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5769 then the caller guarantees that the source and destination pointers are
5770 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5771
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5772<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5773<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5774 source location to the destination location, which may overlap. It copies
5775 "len" bytes of memory over. If the argument is known to be aligned to some
5776 boundary, this can be specified as the fourth argument, otherwise it should
5777 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5778
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5779</div>
5780
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5781<!-- _______________________________________________________________________ -->
5782<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5783 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5784</div>
5785
5786<div class="doc_text">
5787
5788<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5789<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]5790 width. Not all targets support all bit widths however.</p>
5791
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5792<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5793 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5794 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5795 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5796 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5797 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5798 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5799 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5800 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5801</pre>
5802
5803<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5804<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5805 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5806
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5807<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5808 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5809
5810<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5811<p>The first argument is a pointer to the destination to fill, the second is the
5812 byte value to fill it with, the third argument is an integer argument
5813 specifying the number of bytes to fill, and the fourth argument is the known
5814 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5815
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5816<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5817 then the caller guarantees that the destination pointer is aligned to that
5818 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5819
5820<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5821<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5822 at the destination location. If the argument is known to be aligned to some
5823 boundary, this can be specified as the fourth argument, otherwise it should
5824 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5825
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5826</div>
5827
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5828<!-- _______________________________________________________________________ -->
5829<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5830 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5831</div>
5832
5833<div class="doc_text">
5834
5835<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5836<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5837 floating point or vector of floating point type. Not all targets support all
5838 types however.</p>
5839
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5840<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5841 declare float @llvm.sqrt.f32(float %Val)
5842 declare double @llvm.sqrt.f64(double %Val)
5843 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5844 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5845 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5846</pre>
5847
5848<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5849<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5850 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5851 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5852 behavior for negative numbers other than -0.0 (which allows for better
5853 optimization, because there is no need to worry about errno being
5854 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]5855
5856<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5857<p>The argument and return value are floating point numbers of the same
5858 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5859
5860<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5861<p>This function returns the sqrt of the specified operand if it is a
5862 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5863
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5864</div>
5865
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5866<!-- _______________________________________________________________________ -->
5867<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5868 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5869</div>
5870
5871<div class="doc_text">
5872
5873<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5874<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5875 floating point or vector of floating point type. Not all targets support all
5876 types however.</p>
5877
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5878<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5879 declare float @llvm.powi.f32(float %Val, i32 %power)
5880 declare double @llvm.powi.f64(double %Val, i32 %power)
5881 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5882 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5883 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5884</pre>
5885
5886<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5887<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5888 specified (positive or negative) power. The order of evaluation of
5889 multiplications is not defined. When a vector of floating point type is
5890 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5891
5892<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5893<p>The second argument is an integer power, and the first is a value to raise to
5894 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5895
5896<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5897<p>This function returns the first value raised to the second power with an
5898 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5899
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5900</div>
5901
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5902<!-- _______________________________________________________________________ -->
5903<div class="doc_subsubsection">
5904 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5905</div>
5906
5907<div class="doc_text">
5908
5909<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5910<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5911 floating point or vector of floating point type. Not all targets support all
5912 types however.</p>
5913
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5914<pre>
5915 declare float @llvm.sin.f32(float %Val)
5916 declare double @llvm.sin.f64(double %Val)
5917 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5918 declare fp128 @llvm.sin.f128(fp128 %Val)
5919 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5920</pre>
5921
5922<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5923<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5924
5925<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5926<p>The argument and return value are floating point numbers of the same
5927 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5928
5929<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5930<p>This function returns the sine of the specified operand, returning the same
5931 values as the libm <tt>sin</tt> functions would, and handles error conditions
5932 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5933
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5934</div>
5935
5936<!-- _______________________________________________________________________ -->
5937<div class="doc_subsubsection">
5938 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5939</div>
5940
5941<div class="doc_text">
5942
5943<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5944<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5945 floating point or vector of floating point type. Not all targets support all
5946 types however.</p>
5947
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5948<pre>
5949 declare float @llvm.cos.f32(float %Val)
5950 declare double @llvm.cos.f64(double %Val)
5951 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5952 declare fp128 @llvm.cos.f128(fp128 %Val)
5953 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5954</pre>
5955
5956<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5957<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5958
5959<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5960<p>The argument and return value are floating point numbers of the same
5961 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5962
5963<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5964<p>This function returns the cosine of the specified operand, returning the same
5965 values as the libm <tt>cos</tt> functions would, and handles error conditions
5966 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5967
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5968</div>
5969
5970<!-- _______________________________________________________________________ -->
5971<div class="doc_subsubsection">
5972 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5973</div>
5974
5975<div class="doc_text">
5976
5977<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5978<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5979 floating point or vector of floating point type. Not all targets support all
5980 types however.</p>
5981
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5982<pre>
5983 declare float @llvm.pow.f32(float %Val, float %Power)
5984 declare double @llvm.pow.f64(double %Val, double %Power)
5985 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5986 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5987 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5988</pre>
5989
5990<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5991<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5992 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5993
5994<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5995<p>The second argument is a floating point power, and the first is a value to
5996 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5997
5998<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5999<p>This function returns the first value raised to the second power, returning
6000 the same values as the libm <tt>pow</tt> functions would, and handles error
6001 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6002
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6003</div>
6004
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6005<!-- ======================================================================= -->
6006<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6007 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6008</div>
6009
6010<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6011
6012<p>LLVM provides intrinsics for a few important bit manipulation operations.
6013 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6014
6015</div>
6016
6017<!-- _______________________________________________________________________ -->
6018<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6019 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6020</div>
6021
6022<div class="doc_text">
6023
6024<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6025<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6026 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6027
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6028<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6029 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6030 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6031 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6032</pre>
6033
6034<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6035<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6036 values with an even number of bytes (positive multiple of 16 bits). These
6037 are useful for performing operations on data that is not in the target's
6038 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6039
6040<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6041<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6042 and low byte of the input i16 swapped. Similarly,
6043 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6044 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6045 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6046 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6047 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6048 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6049
6050</div>
6051
6052<!-- _______________________________________________________________________ -->
6053<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6054 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6055</div>
6056
6057<div class="doc_text">
6058
6059<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6060<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]6061 width. Not all targets support all bit widths however.</p>
6062
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6063<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6064 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6065 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6066 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6067 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6068 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6069</pre>
6070
6071<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6072<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6073 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6074
6075<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6076<p>The only argument is the value to be counted. The argument may be of any
6077 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6078
6079<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6080<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]6081
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6082</div>
6083
6084<!-- _______________________________________________________________________ -->
6085<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6086 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6087</div>
6088
6089<div class="doc_text">
6090
6091<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6092<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6093 integer bit width. Not all targets support all bit widths however.</p>
6094
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6095<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6096 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6097 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6098 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6099 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6100 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6101</pre>
6102
6103<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6104<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6105 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6106
6107<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6108<p>The only argument is the value to be counted. The argument may be of any
6109 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6110
6111<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6112<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6113 zeros in a variable. If the src == 0 then the result is the size in bits of
6114 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6115
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6116</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6117
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6118<!-- _______________________________________________________________________ -->
6119<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6120 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6121</div>
6122
6123<div class="doc_text">
6124
6125<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6126<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6127 integer bit width. Not all targets support all bit widths however.</p>
6128
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6129<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6130 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6131 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6132 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6133 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6134 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6135</pre>
6136
6137<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6138<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6139 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6140
6141<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6142<p>The only argument is the value to be counted. The argument may be of any
6143 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6144
6145<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6146<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6147 zeros in a variable. If the src == 0 then the result is the size in bits of
6148 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6149
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6150</div>
6151
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6152<!-- ======================================================================= -->
6153<div class="doc_subsection">
6154 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6155</div>
6156
6157<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6158
6159<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6160
6161</div>
6162
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6163<!-- _______________________________________________________________________ -->
6164<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6165 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6166</div>
6167
6168<div class="doc_text">
6169
6170<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6171<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]6172 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6173
6174<pre>
6175 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6176 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6177 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6178</pre>
6179
6180<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6181<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6182 a signed addition of the two arguments, and indicate whether an overflow
6183 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6184
6185<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6186<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]6187 be of integer types of any bit width, but they must have the same bit
6188 width. The second element of the result structure must be of
6189 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6190 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6191
6192<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6193<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6194 a signed addition of the two variables. They return a structure &mdash; the
6195 first element of which is the signed summation, and the second element of
6196 which is a bit specifying if the signed summation resulted in an
6197 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6198
6199<h5>Examples:</h5>
6200<pre>
6201 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6202 %sum = extractvalue {i32, i1} %res, 0
6203 %obit = extractvalue {i32, i1} %res, 1
6204 br i1 %obit, label %overflow, label %normal
6205</pre>
6206
6207</div>
6208
6209<!-- _______________________________________________________________________ -->
6210<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6211 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6212</div>
6213
6214<div class="doc_text">
6215
6216<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6217<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]6218 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6219
6220<pre>
6221 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6222 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6223 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6224</pre>
6225
6226<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6227<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6228 an unsigned addition of the two arguments, and indicate whether a carry
6229 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6230
6231<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6232<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]6233 be of integer types of any bit width, but they must have the same bit
6234 width. The second element of the result structure must be of
6235 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6236 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6237
6238<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6239<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6240 an unsigned addition of the two arguments. They return a structure &mdash;
6241 the first element of which is the sum, and the second element of which is a
6242 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6243
6244<h5>Examples:</h5>
6245<pre>
6246 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6247 %sum = extractvalue {i32, i1} %res, 0
6248 %obit = extractvalue {i32, i1} %res, 1
6249 br i1 %obit, label %carry, label %normal
6250</pre>
6251
6252</div>
6253
6254<!-- _______________________________________________________________________ -->
6255<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6256 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6257</div>
6258
6259<div class="doc_text">
6260
6261<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6262<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]6263 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6264
6265<pre>
6266 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6267 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6268 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6269</pre>
6270
6271<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6272<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6273 a signed subtraction of the two arguments, and indicate whether an overflow
6274 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6275
6276<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6277<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]6278 be of integer types of any bit width, but they must have the same bit
6279 width. The second element of the result structure must be of
6280 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6281 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6282
6283<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6284<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6285 a signed subtraction of the two arguments. They return a structure &mdash;
6286 the first element of which is the subtraction, and the second element of
6287 which is a bit specifying if the signed subtraction resulted in an
6288 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6289
6290<h5>Examples:</h5>
6291<pre>
6292 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6293 %sum = extractvalue {i32, i1} %res, 0
6294 %obit = extractvalue {i32, i1} %res, 1
6295 br i1 %obit, label %overflow, label %normal
6296</pre>
6297
6298</div>
6299
6300<!-- _______________________________________________________________________ -->
6301<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6302 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6303</div>
6304
6305<div class="doc_text">
6306
6307<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6308<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]6309 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6310
6311<pre>
6312 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6313 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6314 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6315</pre>
6316
6317<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6318<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6319 an unsigned subtraction of the two arguments, and indicate whether an
6320 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6321
6322<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6323<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]6324 be of integer types of any bit width, but they must have the same bit
6325 width. The second element of the result structure must be of
6326 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6327 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6328
6329<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6330<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6331 an unsigned subtraction of the two arguments. They return a structure &mdash;
6332 the first element of which is the subtraction, and the second element of
6333 which is a bit specifying if the unsigned subtraction resulted in an
6334 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6335
6336<h5>Examples:</h5>
6337<pre>
6338 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6339 %sum = extractvalue {i32, i1} %res, 0
6340 %obit = extractvalue {i32, i1} %res, 1
6341 br i1 %obit, label %overflow, label %normal
6342</pre>
6343
6344</div>
6345
6346<!-- _______________________________________________________________________ -->
6347<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6348 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6349</div>
6350
6351<div class="doc_text">
6352
6353<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6354<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]6355 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6356
6357<pre>
6358 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6359 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6360 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6361</pre>
6362
6363<h5>Overview:</h5>
6364
6365<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6366 a signed multiplication of the two arguments, and indicate whether an
6367 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6368
6369<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6370<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]6371 be of integer types of any bit width, but they must have the same bit
6372 width. The second element of the result structure must be of
6373 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6374 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6375
6376<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6377<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6378 a signed multiplication of the two arguments. They return a structure &mdash;
6379 the first element of which is the multiplication, and the second element of
6380 which is a bit specifying if the signed multiplication resulted in an
6381 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6382
6383<h5>Examples:</h5>
6384<pre>
6385 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6386 %sum = extractvalue {i32, i1} %res, 0
6387 %obit = extractvalue {i32, i1} %res, 1
6388 br i1 %obit, label %overflow, label %normal
6389</pre>
6390
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6391</div>
6392
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6393<!-- _______________________________________________________________________ -->
6394<div class="doc_subsubsection">
6395 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6396</div>
6397
6398<div class="doc_text">
6399
6400<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6401<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]6402 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6403
6404<pre>
6405 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6406 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6407 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6408</pre>
6409
6410<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6411<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6412 a unsigned multiplication of the two arguments, and indicate whether an
6413 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6414
6415<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6416<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]6417 be of integer types of any bit width, but they must have the same bit
6418 width. The second element of the result structure must be of
6419 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6420 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6421
6422<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6423<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6424 an unsigned multiplication of the two arguments. They return a structure
6425 &mdash; the first element of which is the multiplication, and the second
6426 element of which is a bit specifying if the unsigned multiplication resulted
6427 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6428
6429<h5>Examples:</h5>
6430<pre>
6431 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6432 %sum = extractvalue {i32, i1} %res, 0
6433 %obit = extractvalue {i32, i1} %res, 1
6434 br i1 %obit, label %overflow, label %normal
6435</pre>
6436
6437</div>
6438
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6439<!-- ======================================================================= -->
6440<div class="doc_subsection">
6441 <a name="int_debugger">Debugger Intrinsics</a>
6442</div>
6443
6444<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6445
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6446<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6447 prefix), are described in
6448 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6449 Level Debugging</a> document.</p>
6450
6451</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6452
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6453<!-- ======================================================================= -->
6454<div class="doc_subsection">
6455 <a name="int_eh">Exception Handling Intrinsics</a>
6456</div>
6457
6458<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6459
6460<p>The LLVM exception handling intrinsics (which all start with
6461 <tt>llvm.eh.</tt> prefix), are described in
6462 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6463 Handling</a> document.</p>
6464
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6465</div>
6466
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6467<!-- ======================================================================= -->
6468<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6469 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6470</div>
6471
6472<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6473
6474<p>This intrinsic makes it possible to excise one parameter, marked with
6475 the <tt>nest</tt> attribute, from a function. The result is a callable
6476 function pointer lacking the nest parameter - the caller does not need to
6477 provide a value for it. Instead, the value to use is stored in advance in a
6478 "trampoline", a block of memory usually allocated on the stack, which also
6479 contains code to splice the nest value into the argument list. This is used
6480 to implement the GCC nested function address extension.</p>
6481
6482<p>For example, if the function is
6483 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6484 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6485 follows:</p>
6486
6487<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6488<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6489 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6490 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6491 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6492 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6493</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6494</div>
6495
6496<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6497 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6498
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6499</div>
6500
6501<!-- _______________________________________________________________________ -->
6502<div class="doc_subsubsection">
6503 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6504</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6505
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6506<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6507
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6508<h5>Syntax:</h5>
6509<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6510 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]6511</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6512
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6513<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6514<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6515 function pointer suitable for executing it.</p>
6516
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6517<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6518<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6519 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6520 sufficiently aligned block of memory; this memory is written to by the
6521 intrinsic. Note that the size and the alignment are target-specific - LLVM
6522 currently provides no portable way of determining them, so a front-end that
6523 generates this intrinsic needs to have some target-specific knowledge.
6524 The <tt>func</tt> argument must hold a function bitcast to
6525 an <tt>i8*</tt>.</p>
6526
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6527<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6528<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6529 dependent code, turning it into a function. A pointer to this function is
6530 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6531 function pointer type</a> before being called. The new function's signature
6532 is the same as that of <tt>func</tt> with any arguments marked with
6533 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6534 is allowed, and it must be of pointer type. Calling the new function is
6535 equivalent to calling <tt>func</tt> with the same argument list, but
6536 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6537 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6538 by <tt>tramp</tt> is modified, then the effect of any later call to the
6539 returned function pointer is undefined.</p>
6540
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6541</div>
6542
6543<!-- ======================================================================= -->
6544<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6545 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6546</div>
6547
6548<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6549
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6550<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6551 hardware constructs for atomic operations and memory synchronization. This
6552 provides an interface to the hardware, not an interface to the programmer. It
6553 is aimed at a low enough level to allow any programming models or APIs
6554 (Application Programming Interfaces) which need atomic behaviors to map
6555 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6556 hardware provides a "universal IR" for source languages, it also provides a
6557 starting point for developing a "universal" atomic operation and
6558 synchronization IR.</p>
6559
6560<p>These do <em>not</em> form an API such as high-level threading libraries,
6561 software transaction memory systems, atomic primitives, and intrinsic
6562 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6563 application libraries. The hardware interface provided by LLVM should allow
6564 a clean implementation of all of these APIs and parallel programming models.
6565 No one model or paradigm should be selected above others unless the hardware
6566 itself ubiquitously does so.</p>
6567
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6568</div>
6569
6570<!-- _______________________________________________________________________ -->
6571<div class="doc_subsubsection">
6572 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6573</div>
6574<div class="doc_text">
6575<h5>Syntax:</h5>
6576<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6577 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]6578</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6579
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6580<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6581<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6582 specific pairs of memory access types.</p>
6583
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6584<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6585<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6586 The first four arguments enables a specific barrier as listed below. The
6587 fith argument specifies that the barrier applies to io or device or uncached
6588 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6589
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6590<ul>
6591 <li><tt>ll</tt>: load-load barrier</li>
6592 <li><tt>ls</tt>: load-store barrier</li>
6593 <li><tt>sl</tt>: store-load barrier</li>
6594 <li><tt>ss</tt>: store-store barrier</li>
6595 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6596</ul>
6597
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6598<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6599<p>This intrinsic causes the system to enforce some ordering constraints upon
6600 the loads and stores of the program. This barrier does not
6601 indicate <em>when</em> any events will occur, it only enforces
6602 an <em>order</em> in which they occur. For any of the specified pairs of load
6603 and store operations (f.ex. load-load, or store-load), all of the first
6604 operations preceding the barrier will complete before any of the second
6605 operations succeeding the barrier begin. Specifically the semantics for each
6606 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6607
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6608<ul>
6609 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6610 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6611 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6612 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6613 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6614 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6615 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6616 load after the barrier begins.</li>
6617</ul>
6618
6619<p>These semantics are applied with a logical "and" behavior when more than one
6620 is enabled in a single memory barrier intrinsic.</p>
6621
6622<p>Backends may implement stronger barriers than those requested when they do
6623 not support as fine grained a barrier as requested. Some architectures do
6624 not need all types of barriers and on such architectures, these become
6625 noops.</p>
6626
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6627<h5>Example:</h5>
6628<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6629%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6630%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6631 store i32 4, %ptr
6632
6633%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6634 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6635 <i>; guarantee the above finishes</i>
6636 store i32 8, %ptr <i>; before this begins</i>
6637</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6638
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6639</div>
6640
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6641<!-- _______________________________________________________________________ -->
6642<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6643 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6644</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6645
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6646<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6647
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6648<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6649<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6650 any integer bit width and for different address spaces. Not all targets
6651 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6652
6653<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6654 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6655 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6656 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6657 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]6658</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6659
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6660<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6661<p>This loads a value in memory and compares it to a given value. If they are
6662 equal, it stores a new value into the memory.</p>
6663
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6664<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6665<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6666 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6667 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6668 this integer type. While any bit width integer may be used, targets may only
6669 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6670
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6671<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6672<p>This entire intrinsic must be executed atomically. It first loads the value
6673 in memory pointed to by <tt>ptr</tt> and compares it with the
6674 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6675 memory. The loaded value is yielded in all cases. This provides the
6676 equivalent of an atomic compare-and-swap operation within the SSA
6677 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6678
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6679<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6680<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6681%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6682%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6683 store i32 4, %ptr
6684
6685%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6686%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6687 <i>; yields {i32}:result1 = 4</i>
6688%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6689%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6690
6691%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6692%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6693 <i>; yields {i32}:result2 = 8</i>
6694%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6695
6696%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6697</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6698
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6699</div>
6700
6701<!-- _______________________________________________________________________ -->
6702<div class="doc_subsubsection">
6703 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6704</div>
6705<div class="doc_text">
6706<h5>Syntax:</h5>
6707
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6708<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6709 integer bit width. Not all targets support all bit widths however.</p>
6710
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6711<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6712 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6713 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6714 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6715 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]6716</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6717
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6718<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6719<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6720 the value from memory. It then stores the value in <tt>val</tt> in the memory
6721 at <tt>ptr</tt>.</p>
6722
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6723<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6724<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6725 the <tt>val</tt> argument and the result must be integers of the same bit
6726 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6727 integer type. The targets may only lower integer representations they
6728 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6729
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6730<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6731<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6732 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6733 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6734
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6735<h5>Examples:</h5>
6736<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6737%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6738%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6739 store i32 4, %ptr
6740
6741%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6742%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6743 <i>; yields {i32}:result1 = 4</i>
6744%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6745%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6746
6747%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6748%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6749 <i>; yields {i32}:result2 = 8</i>
6750
6751%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6752%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6753</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6754
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6755</div>
6756
6757<!-- _______________________________________________________________________ -->
6758<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6759 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6760
6761</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6762
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6763<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6764
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6765<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6766<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6767 any integer bit width. Not all targets support all bit widths however.</p>
6768
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6769<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6770 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6771 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6772 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6773 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]6774</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6775
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6776<h5>Overview:</h5>
6777<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6778 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6779
6780<h5>Arguments:</h5>
6781<p>The intrinsic takes two arguments, the first a pointer to an integer value
6782 and the second an integer value. The result is also an integer value. These
6783 integer types can have any bit width, but they must all have the same bit
6784 width. The targets may only lower integer representations they support.</p>
6785
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6786<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6787<p>This intrinsic does a series of operations atomically. It first loads the
6788 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6789 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]6790
6791<h5>Examples:</h5>
6792<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6793%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6794%ptr = bitcast i8* %mallocP to i32*
6795 store i32 4, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6796%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6797 <i>; yields {i32}:result1 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6798%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6799 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6800%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6801 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6802%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6803</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6804
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6805</div>
6806
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6807<!-- _______________________________________________________________________ -->
6808<div class="doc_subsubsection">
6809 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6810
6811</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6812
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6813<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6814
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6815<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6816<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6817 any integer bit width and for different address spaces. Not all targets
6818 support all bit widths however.</p>
6819
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6820<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6821 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6822 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6823 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6824 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]6825</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6826
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6827<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6828<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6829 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6830
6831<h5>Arguments:</h5>
6832<p>The intrinsic takes two arguments, the first a pointer to an integer value
6833 and the second an integer value. The result is also an integer value. These
6834 integer types can have any bit width, but they must all have the same bit
6835 width. The targets may only lower integer representations they support.</p>
6836
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6837<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6838<p>This intrinsic does a series of operations atomically. It first loads the
6839 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6840 result to <tt>ptr</tt>. It yields the original value stored
6841 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6842
6843<h5>Examples:</h5>
6844<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6845%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6846%ptr = bitcast i8* %mallocP to i32*
6847 store i32 8, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6848%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6849 <i>; yields {i32}:result1 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6850%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6851 <i>; yields {i32}:result2 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6852%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6853 <i>; yields {i32}:result3 = 2</i>
6854%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6855</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6856
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6857</div>
6858
6859<!-- _______________________________________________________________________ -->
6860<div class="doc_subsubsection">
6861 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6862 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6863 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6864 <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]6865</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6866
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6867<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6868
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6869<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6870<p>These are overloaded intrinsics. You can
6871 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6872 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6873 bit width and for different address spaces. Not all targets support all bit
6874 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6875
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6876<pre>
6877 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6878 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6879 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6880 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]6881</pre>
6882
6883<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6884 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6885 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6886 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6887 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]6888</pre>
6889
6890<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6891 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6892 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6893 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6894 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]6895</pre>
6896
6897<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6898 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6899 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6900 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6901 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]6902</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6903
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6904<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6905<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6906 the value stored in memory at <tt>ptr</tt>. It yields the original value
6907 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6908
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6909<h5>Arguments:</h5>
6910<p>These intrinsics take two arguments, the first a pointer to an integer value
6911 and the second an integer value. The result is also an integer value. These
6912 integer types can have any bit width, but they must all have the same bit
6913 width. The targets may only lower integer representations they support.</p>
6914
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6915<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6916<p>These intrinsics does a series of operations atomically. They first load the
6917 value stored at <tt>ptr</tt>. They then do the bitwise
6918 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6919 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6920
6921<h5>Examples:</h5>
6922<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6923%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6924%ptr = bitcast i8* %mallocP to i32*
6925 store i32 0x0F0F, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6926%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6927 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6928%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6929 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6930%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6931 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6932%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6933 <i>; yields {i32}:result3 = FF</i>
6934%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6935</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6936
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6937</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6938
6939<!-- _______________________________________________________________________ -->
6940<div class="doc_subsubsection">
6941 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6942 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6943 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6944 <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]6945</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6946
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6947<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6948
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6949<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6950<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6951 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6952 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6953 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6954
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6955<pre>
6956 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6957 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6958 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6959 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]6960</pre>
6961
6962<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6963 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6964 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6965 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6966 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]6967</pre>
6968
6969<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6970 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6971 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6972 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6973 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]6974</pre>
6975
6976<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6977 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6978 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6979 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6980 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]6981</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6982
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6983<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6984<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6985 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6986 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6987
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6988<h5>Arguments:</h5>
6989<p>These intrinsics take two arguments, the first a pointer to an integer value
6990 and the second an integer value. The result is also an integer value. These
6991 integer types can have any bit width, but they must all have the same bit
6992 width. The targets may only lower integer representations they support.</p>
6993
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6994<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6995<p>These intrinsics does a series of operations atomically. They first load the
6996 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6997 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6998 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6999
7000<h5>Examples:</h5>
7001<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7002%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7003%ptr = bitcast i8* %mallocP to i32*
7004 store i32 7, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7005%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7006 <i>; yields {i32}:result0 = 7</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7007%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7008 <i>; yields {i32}:result1 = -2</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7009%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7010 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7011%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7012 <i>; yields {i32}:result3 = 8</i>
7013%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7014</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7015
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7016</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7017
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7018
7019<!-- ======================================================================= -->
7020<div class="doc_subsection">
7021 <a name="int_memorymarkers">Memory Use Markers</a>
7022</div>
7023
7024<div class="doc_text">
7025
7026<p>This class of intrinsics exists to information about the lifetime of memory
7027 objects and ranges where variables are immutable.</p>
7028
7029</div>
7030
7031<!-- _______________________________________________________________________ -->
7032<div class="doc_subsubsection">
7033 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7034</div>
7035
7036<div class="doc_text">
7037
7038<h5>Syntax:</h5>
7039<pre>
7040 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7041</pre>
7042
7043<h5>Overview:</h5>
7044<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7045 object's lifetime.</p>
7046
7047<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7048<p>The first argument is a constant integer representing the size of the
7049 object, or -1 if it is variable sized. The second argument is a pointer to
7050 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7051
7052<h5>Semantics:</h5>
7053<p>This intrinsic indicates that before this point in the code, the value of the
7054 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewyckyd20fd592009-10-27 16:56:58 +0000[diff] [blame]7055 never be used and has an undefined value. A load from the pointer that
7056 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7057 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7058
7059</div>
7060
7061<!-- _______________________________________________________________________ -->
7062<div class="doc_subsubsection">
7063 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7064</div>
7065
7066<div class="doc_text">
7067
7068<h5>Syntax:</h5>
7069<pre>
7070 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7071</pre>
7072
7073<h5>Overview:</h5>
7074<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7075 object's lifetime.</p>
7076
7077<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7078<p>The first argument is a constant integer representing the size of the
7079 object, or -1 if it is variable sized. The second argument is a pointer to
7080 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7081
7082<h5>Semantics:</h5>
7083<p>This intrinsic indicates that after this point in the code, the value of the
7084 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7085 never be used and has an undefined value. Any stores into the memory object
7086 following this intrinsic may be removed as dead.
7087
7088</div>
7089
7090<!-- _______________________________________________________________________ -->
7091<div class="doc_subsubsection">
7092 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7093</div>
7094
7095<div class="doc_text">
7096
7097<h5>Syntax:</h5>
7098<pre>
7099 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7100</pre>
7101
7102<h5>Overview:</h5>
7103<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7104 a memory object will not change.</p>
7105
7106<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7107<p>The first argument is a constant integer representing the size of the
7108 object, or -1 if it is variable sized. The second argument is a pointer to
7109 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7110
7111<h5>Semantics:</h5>
7112<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7113 the return value, the referenced memory location is constant and
7114 unchanging.</p>
7115
7116</div>
7117
7118<!-- _______________________________________________________________________ -->
7119<div class="doc_subsubsection">
7120 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7121</div>
7122
7123<div class="doc_text">
7124
7125<h5>Syntax:</h5>
7126<pre>
7127 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7128</pre>
7129
7130<h5>Overview:</h5>
7131<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7132 a memory object are mutable.</p>
7133
7134<h5>Arguments:</h5>
7135<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7136 The second argument is a constant integer representing the size of the
7137 object, or -1 if it is variable sized and the third argument is a pointer
7138 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7139
7140<h5>Semantics:</h5>
7141<p>This intrinsic indicates that the memory is mutable again.</p>
7142
7143</div>
7144
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7145<!-- ======================================================================= -->
7146<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7147 <a name="int_general">General Intrinsics</a>
7148</div>
7149
7150<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7151
7152<p>This class of intrinsics is designed to be generic and has no specific
7153 purpose.</p>
7154
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7155</div>
7156
7157<!-- _______________________________________________________________________ -->
7158<div class="doc_subsubsection">
7159 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7160</div>
7161
7162<div class="doc_text">
7163
7164<h5>Syntax:</h5>
7165<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]7166 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]7167</pre>
7168
7169<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7170<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7171
7172<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7173<p>The first argument is a pointer to a value, the second is a pointer to a
7174 global string, the third is a pointer to a global string which is the source
7175 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7176
7177<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7178<p>This intrinsic allows annotation of local variables with arbitrary strings.
7179 This can be useful for special purpose optimizations that want to look for
7180 these annotations. These have no other defined use, they are ignored by code
7181 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7182
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7183</div>
7184
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7185<!-- _______________________________________________________________________ -->
7186<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7187 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7188</div>
7189
7190<div class="doc_text">
7191
7192<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7193<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7194 any integer bit width.</p>
7195
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7196<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]7197 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7198 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7199 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7200 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7201 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]7202</pre>
7203
7204<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7205<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7206
7207<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7208<p>The first argument is an integer value (result of some expression), the
7209 second is a pointer to a global string, the third is a pointer to a global
7210 string which is the source file name, and the last argument is the line
7211 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7212
7213<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7214<p>This intrinsic allows annotations to be put on arbitrary expressions with
7215 arbitrary strings. This can be useful for special purpose optimizations that
7216 want to look for these annotations. These have no other defined use, they
7217 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7218
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7219</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7220
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7221<!-- _______________________________________________________________________ -->
7222<div class="doc_subsubsection">
7223 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7224</div>
7225
7226<div class="doc_text">
7227
7228<h5>Syntax:</h5>
7229<pre>
7230 declare void @llvm.trap()
7231</pre>
7232
7233<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7234<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7235
7236<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7237<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7238
7239<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7240<p>This intrinsics is lowered to the target dependent trap instruction. If the
7241 target does not have a trap instruction, this intrinsic will be lowered to
7242 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7243
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7244</div>
7245
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7246<!-- _______________________________________________________________________ -->
7247<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7248 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7249</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7250
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7251<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7252
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7253<h5>Syntax:</h5>
7254<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7255 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7256</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7257
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7258<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7259<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7260 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7261 ensure that it is placed on the stack before local variables.</p>
7262
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7263<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7264<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7265 arguments. The first argument is the value loaded from the stack
7266 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7267 that has enough space to hold the value of the guard.</p>
7268
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7269<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7270<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7271 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7272 stack. This is to ensure that if a local variable on the stack is
7273 overwritten, it will destroy the value of the guard. When the function exits,
7274 the guard on the stack is checked against the original guard. If they're
7275 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7276 function.</p>
7277
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7278</div>
7279
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7280<!-- _______________________________________________________________________ -->
7281<div class="doc_subsubsection">
7282 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7283</div>
7284
7285<div class="doc_text">
7286
7287<h5>Syntax:</h5>
7288<pre>
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7289 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7290 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7291</pre>
7292
7293<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7294<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7295 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7296 operation like memcpy will either overflow a buffer that corresponds to
7297 an object, or b) to determine that a runtime check for overflow isn't
7298 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7299 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7300
7301<h5>Arguments:</h5>
7302<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7303 argument is a pointer to or into the <tt>object</tt>. The second argument
7304 is a boolean 0 or 1. This argument determines whether you want the
7305 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7306 1, variables are not allowed.</p>
7307
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7308<h5>Semantics:</h5>
7309<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7310 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7311 (depending on the <tt>type</tt> argument if the size cannot be determined
7312 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7313
7314</div>
7315
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7316<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7317<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7318<address>
7319 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7320 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7321 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7322 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7323
7324 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7325 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7326 Last modified: $Date$
7327</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7328
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7329</body>
7330</html>