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gerrit-public.fairphone.software / toolchain / llvm-project / 1ad1499d14fd3c7acba3cca92cacc01b93941275 / . / 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>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]46 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]47 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]48 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]49 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]50 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]51 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]52 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]53 </ol>
54 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]55 <li><a href="#typesystem">Type System</a>
56 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]57 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]58 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]59 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]60 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]61 <li><a href="#t_floating">Floating Point Types</a></li>
62 <li><a href="#t_void">Void Type</a></li>
63 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]64 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]65 </ol>
66 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]67 <li><a href="#t_derived">Derived Types</a>
68 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]69 <li><a href="#t_aggregate">Aggregate Types</a>
70 <ol>
71 <li><a href="#t_array">Array Type</a></li>
72 <li><a href="#t_struct">Structure Type</a></li>
73 <li><a href="#t_pstruct">Packed Structure Type</a></li>
74 <li><a href="#t_union">Union Type</a></li>
75 <li><a href="#t_vector">Vector Type</a></li>
76 </ol>
77 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]78 <li><a href="#t_function">Function Type</a></li>
79 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]80 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]81 </ol>
82 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]83 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]84 </ol>
85 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]86 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]87 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]88 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]89 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]90 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
91 <li><a href="#undefvalues">Undefined Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]92 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]94 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]95 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]96 <li><a href="#othervalues">Other Values</a>
97 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]98 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]99 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]102 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
103 <ol>
104 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]105 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
106 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]107 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
108 Global Variable</a></li>
109 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
110 Global Variable</a></li>
111 </ol>
112 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]113 <li><a href="#instref">Instruction Reference</a>
114 <ol>
115 <li><a href="#terminators">Terminator Instructions</a>
116 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]117 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
118 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]119 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]120 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]121 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]123 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]124 </ol>
125 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]126 <li><a href="#binaryops">Binary Operations</a>
127 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]128 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]129 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]130 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]131 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]134 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
135 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
136 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]137 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
138 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
139 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]140 </ol>
141 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]142 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
143 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]144 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
145 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
146 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]147 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]149 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]150 </ol>
151 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]152 <li><a href="#vectorops">Vector Operations</a>
153 <ol>
154 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
155 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
156 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]157 </ol>
158 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]159 <li><a href="#aggregateops">Aggregate Operations</a>
160 <ol>
161 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
162 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
163 </ol>
164 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]165 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]166 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]167 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]168 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
169 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
170 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]171 </ol>
172 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]173 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]174 <ol>
175 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
176 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
177 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
178 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
179 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]180 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
182 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
183 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]184 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
185 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]186 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]187 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]188 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]189 <li><a href="#otherops">Other Operations</a>
190 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]191 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
192 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]193 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]194 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]195 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]196 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]197 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]198 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]199 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]200 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]201 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]202 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]203 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
204 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]205 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
206 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
207 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]208 </ol>
209 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]210 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
211 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]212 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
213 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
214 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]215 </ol>
216 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]217 <li><a href="#int_codegen">Code Generator Intrinsics</a>
218 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]219 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
220 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
221 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
222 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
223 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
224 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
225 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]226 </ol>
227 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]228 <li><a href="#int_libc">Standard C Library Intrinsics</a>
229 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]230 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
232 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
233 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]235 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]238 </ol>
239 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]240 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]241 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]242 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]243 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
244 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
245 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]246 </ol>
247 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]248 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
249 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]250 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
251 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
252 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
253 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
254 <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]255 <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]256 </ol>
257 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]258 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]259 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]260 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]261 <ol>
262 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]263 </ol>
264 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]265 <li><a href="#int_atomics">Atomic intrinsics</a>
266 <ol>
267 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
268 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
269 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
270 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
271 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
272 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
273 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
274 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
275 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
276 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
277 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
278 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
279 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
280 </ol>
281 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]282 <li><a href="#int_memorymarkers">Memory Use Markers</a>
283 <ol>
284 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
285 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
286 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
287 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
288 </ol>
289 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]290 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]291 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]292 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]293 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]294 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]295 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]296 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]297 '<tt>llvm.trap</tt>' Intrinsic</a></li>
298 <li><a href="#int_stackprotector">
299 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]300 <li><a href="#int_objectsize">
301 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]302 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]303 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]304 </ol>
305 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]306</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]307
308<div class="doc_author">
309 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
310 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]311</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]312
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]313<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]314<div class="doc_section"> <a name="abstract">Abstract </a></div>
315<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]316
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]317<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]318
319<p>This document is a reference manual for the LLVM assembly language. LLVM is
320 a Static Single Assignment (SSA) based representation that provides type
321 safety, low-level operations, flexibility, and the capability of representing
322 'all' high-level languages cleanly. It is the common code representation
323 used throughout all phases of the LLVM compilation strategy.</p>
324
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]325</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]326
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]327<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]328<div class="doc_section"> <a name="introduction">Introduction</a> </div>
329<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]330
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]331<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]332
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]333<p>The LLVM code representation is designed to be used in three different forms:
334 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
335 for fast loading by a Just-In-Time compiler), and as a human readable
336 assembly language representation. This allows LLVM to provide a powerful
337 intermediate representation for efficient compiler transformations and
338 analysis, while providing a natural means to debug and visualize the
339 transformations. The three different forms of LLVM are all equivalent. This
340 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]341
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM representation aims to be light-weight and low-level while being
343 expressive, typed, and extensible at the same time. It aims to be a
344 "universal IR" of sorts, by being at a low enough level that high-level ideas
345 may be cleanly mapped to it (similar to how microprocessors are "universal
346 IR's", allowing many source languages to be mapped to them). By providing
347 type information, LLVM can be used as the target of optimizations: for
348 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]349 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]350 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]351
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]352</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]353
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]354<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]355<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]356
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]357<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]358
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]359<p>It is important to note that this document describes 'well formed' LLVM
360 assembly language. There is a difference between what the parser accepts and
361 what is considered 'well formed'. For example, the following instruction is
362 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]363
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]364<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]365<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]366%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]367</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]368</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]369
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]370<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
371 LLVM infrastructure provides a verification pass that may be used to verify
372 that an LLVM module is well formed. This pass is automatically run by the
373 parser after parsing input assembly and by the optimizer before it outputs
374 bitcode. The violations pointed out by the verifier pass indicate bugs in
375 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]376
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]377</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]378
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]379<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]380
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]381<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]382<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]383<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]384
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]385<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]386
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]387<p>LLVM identifiers come in two basic types: global and local. Global
388 identifiers (functions, global variables) begin with the <tt>'@'</tt>
389 character. Local identifiers (register names, types) begin with
390 the <tt>'%'</tt> character. Additionally, there are three different formats
391 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]392
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]393<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]394 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]395 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
396 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
397 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
398 other characters in their names can be surrounded with quotes. Special
399 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
400 ASCII code for the character in hexadecimal. In this way, any character
401 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]402
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]403 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]404 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]405
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]406 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]407 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]408</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]409
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]410<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]411 don't need to worry about name clashes with reserved words, and the set of
412 reserved words may be expanded in the future without penalty. Additionally,
413 unnamed identifiers allow a compiler to quickly come up with a temporary
414 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]415
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]416<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]417 languages. There are keywords for different opcodes
418 ('<tt><a href="#i_add">add</a></tt>',
419 '<tt><a href="#i_bitcast">bitcast</a></tt>',
420 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
421 ('<tt><a href="#t_void">void</a></tt>',
422 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
423 reserved words cannot conflict with variable names, because none of them
424 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]425
426<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]427 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]428
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]429<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]430
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]431<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]432<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]433%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]434</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]435</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]437<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]438
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]439<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]440<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]441%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]442</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]443</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]444
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]445<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]446
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]447<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448<pre>
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]449%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
450%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]451%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]452</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]453</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]455<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
456 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]457
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]458<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]459 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]460 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]461
462 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]463 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]464
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]465 <li>Unnamed temporaries are numbered sequentially</li>
466</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]467
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]468<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]469 demonstrating instructions, we will follow an instruction with a comment that
470 defines the type and name of value produced. Comments are shown in italic
471 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]472
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]473</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]474
475<!-- *********************************************************************** -->
476<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
477<!-- *********************************************************************** -->
478
479<!-- ======================================================================= -->
480<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
481</div>
482
483<div class="doc_text">
484
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]485<p>LLVM programs are composed of "Module"s, each of which is a translation unit
486 of the input programs. Each module consists of functions, global variables,
487 and symbol table entries. Modules may be combined together with the LLVM
488 linker, which merges function (and global variable) definitions, resolves
489 forward declarations, and merges symbol table entries. Here is an example of
490 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]491
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]492<div class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]493<pre>
494<i>; Declare the string constant as a global constant.</i>
495<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]496
497<i>; External declaration of the puts function</i>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]498<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]499
500<i>; Definition of main function</i>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]501define i32 @main() { <i>; i32()* </i>
502 <i>; Convert [13 x i8]* to i8 *...</i>
503 %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]504
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]505 <i>; Call puts function to write out the string to stdout.</i>
506 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]507 <a href="#i_ret">ret</a> i32 0<br>}
508
509<i>; Named metadata</i>
510!1 = metadata !{i32 41}
511!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]512</pre>
513</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]514
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]515<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]516 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]517 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]518 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
519 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]520
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]521<p>In general, a module is made up of a list of global values, where both
522 functions and global variables are global values. Global values are
523 represented by a pointer to a memory location (in this case, a pointer to an
524 array of char, and a pointer to a function), and have one of the
525 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]526
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]527</div>
528
529<!-- ======================================================================= -->
530<div class="doc_subsection">
531 <a name="linkage">Linkage Types</a>
532</div>
533
534<div class="doc_text">
535
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]536<p>All Global Variables and Functions have one of the following types of
537 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]538
539<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]540 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]541 <dd>Global values with private linkage are only directly accessible by objects
542 in the current module. In particular, linking code into a module with an
543 private global value may cause the private to be renamed as necessary to
544 avoid collisions. Because the symbol is private to the module, all
545 references can be updated. This doesn't show up in any symbol table in the
546 object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]547
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]549 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere7f064e2009-08-24 04:32:16 +0000[diff] [blame]550 removed by the linker after evaluation. Note that (unlike private
551 symbols) linker_private symbols are subject to coalescing by the linker:
552 weak symbols get merged and redefinitions are rejected. However, unlike
553 normal strong symbols, they are removed by the linker from the final
554 linked image (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]555
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]557 <dd>Similar to private, but the value shows as a local symbol
558 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
559 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]560
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]562 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]563 into the object file corresponding to the LLVM module. They exist to
564 allow inlining and other optimizations to take place given knowledge of
565 the definition of the global, which is known to be somewhere outside the
566 module. Globals with <tt>available_externally</tt> linkage are allowed to
567 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
568 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]569
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]571 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]572 the same name when linkage occurs. This can be used to implement
573 some forms of inline functions, templates, or other code which must be
574 generated in each translation unit that uses it, but where the body may
575 be overridden with a more definitive definition later. Unreferenced
576 <tt>linkonce</tt> globals are allowed to be discarded. Note that
577 <tt>linkonce</tt> linkage does not actually allow the optimizer to
578 inline the body of this function into callers because it doesn't know if
579 this definition of the function is the definitive definition within the
580 program or whether it will be overridden by a stronger definition.
581 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
582 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]583
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]585 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
586 <tt>linkonce</tt> linkage, except that unreferenced globals with
587 <tt>weak</tt> linkage may not be discarded. This is used for globals that
588 are declared "weak" in C source code.</dd>
589
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]591 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
592 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
593 global scope.
594 Symbols with "<tt>common</tt>" linkage are merged in the same way as
595 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]596 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]597 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]598 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
599 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]600
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]601
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]602 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]603 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]604 pointer to array type. When two global variables with appending linkage
605 are linked together, the two global arrays are appended together. This is
606 the LLVM, typesafe, equivalent of having the system linker append together
607 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]608
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]609 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]610 <dd>The semantics of this linkage follow the ELF object file model: the symbol
611 is weak until linked, if not linked, the symbol becomes null instead of
612 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]613
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]614 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
615 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]616 <dd>Some languages allow differing globals to be merged, such as two functions
617 with different semantics. Other languages, such as <tt>C++</tt>, ensure
618 that only equivalent globals are ever merged (the "one definition rule" -
619 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
620 and <tt>weak_odr</tt> linkage types to indicate that the global will only
621 be merged with equivalent globals. These linkage types are otherwise the
622 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]623
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]624 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]625 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]626 visible, meaning that it participates in linkage and can be used to
627 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]628</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]629
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]630<p>The next two types of linkage are targeted for Microsoft Windows platform
631 only. They are designed to support importing (exporting) symbols from (to)
632 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]633
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]634<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]635 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]636 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]637 or variable via a global pointer to a pointer that is set up by the DLL
638 exporting the symbol. On Microsoft Windows targets, the pointer name is
639 formed by combining <code>__imp_</code> and the function or variable
640 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]641
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]642 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]643 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]644 pointer to a pointer in a DLL, so that it can be referenced with the
645 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
646 name is formed by combining <code>__imp_</code> and the function or
647 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]648</dl>
649
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]650<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
651 another module defined a "<tt>.LC0</tt>" variable and was linked with this
652 one, one of the two would be renamed, preventing a collision. Since
653 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
654 declarations), they are accessible outside of the current module.</p>
655
656<p>It is illegal for a function <i>declaration</i> to have any linkage type
657 other than "externally visible", <tt>dllimport</tt>
658 or <tt>extern_weak</tt>.</p>
659
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]660<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]661 or <tt>weak_odr</tt> linkages.</p>
662
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]663</div>
664
665<!-- ======================================================================= -->
666<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]667 <a name="callingconv">Calling Conventions</a>
668</div>
669
670<div class="doc_text">
671
672<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]673 and <a href="#i_invoke">invokes</a> can all have an optional calling
674 convention specified for the call. The calling convention of any pair of
675 dynamic caller/callee must match, or the behavior of the program is
676 undefined. The following calling conventions are supported by LLVM, and more
677 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]678
679<dl>
680 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]681 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]682 specified) matches the target C calling conventions. This calling
683 convention supports varargs function calls and tolerates some mismatch in
684 the declared prototype and implemented declaration of the function (as
685 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]686
687 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]688 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]689 (e.g. by passing things in registers). This calling convention allows the
690 target to use whatever tricks it wants to produce fast code for the
691 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]692 (Application Binary Interface).
693 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
694 when this convention is used.</a> This calling convention does not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]695 support varargs and requires the prototype of all callees to exactly match
696 the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]697
698 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]699 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]700 as possible under the assumption that the call is not commonly executed.
701 As such, these calls often preserve all registers so that the call does
702 not break any live ranges in the caller side. This calling convention
703 does not support varargs and requires the prototype of all callees to
704 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]705
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]706 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]708 target-specific calling conventions to be used. Target specific calling
709 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]710</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]711
712<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]713 support Pascal conventions or any other well-known target-independent
714 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]715
716</div>
717
718<!-- ======================================================================= -->
719<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]720 <a name="visibility">Visibility Styles</a>
721</div>
722
723<div class="doc_text">
724
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]725<p>All Global Variables and Functions have one of the following visibility
726 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]727
728<dl>
729 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]730 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]731 that the declaration is visible to other modules and, in shared libraries,
732 means that the declared entity may be overridden. On Darwin, default
733 visibility means that the declaration is visible to other modules. Default
734 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]735
736 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]737 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]738 object if they are in the same shared object. Usually, hidden visibility
739 indicates that the symbol will not be placed into the dynamic symbol
740 table, so no other module (executable or shared library) can reference it
741 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]742
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]743 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]744 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]745 the dynamic symbol table, but that references within the defining module
746 will bind to the local symbol. That is, the symbol cannot be overridden by
747 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]748</dl>
749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]754 <a name="namedtypes">Named Types</a>
755</div>
756
757<div class="doc_text">
758
759<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]760 it easier to read the IR and make the IR more condensed (particularly when
761 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]762
763<div class="doc_code">
764<pre>
765%mytype = type { %mytype*, i32 }
766</pre>
767</div>
768
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]769<p>You may give a name to any <a href="#typesystem">type</a> except
770 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
771 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]772
773<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]774 and that you can therefore specify multiple names for the same type. This
775 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
776 uses structural typing, the name is not part of the type. When printing out
777 LLVM IR, the printer will pick <em>one name</em> to render all types of a
778 particular shape. This means that if you have code where two different
779 source types end up having the same LLVM type, that the dumper will sometimes
780 print the "wrong" or unexpected type. This is an important design point and
781 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]782
783</div>
784
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]785<!-- ======================================================================= -->
786<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]787 <a name="globalvars">Global Variables</a>
788</div>
789
790<div class="doc_text">
791
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]792<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]793 instead of run-time. Global variables may optionally be initialized, may
794 have an explicit section to be placed in, and may have an optional explicit
795 alignment specified. A variable may be defined as "thread_local", which
796 means that it will not be shared by threads (each thread will have a
797 separated copy of the variable). A variable may be defined as a global
798 "constant," which indicates that the contents of the variable
799 will <b>never</b> be modified (enabling better optimization, allowing the
800 global data to be placed in the read-only section of an executable, etc).
801 Note that variables that need runtime initialization cannot be marked
802 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]803
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]804<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
805 constant, even if the final definition of the global is not. This capability
806 can be used to enable slightly better optimization of the program, but
807 requires the language definition to guarantee that optimizations based on the
808 'constantness' are valid for the translation units that do not include the
809 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]810
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]811<p>As SSA values, global variables define pointer values that are in scope
812 (i.e. they dominate) all basic blocks in the program. Global variables
813 always define a pointer to their "content" type because they describe a
814 region of memory, and all memory objects in LLVM are accessed through
815 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]816
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]817<p>A global variable may be declared to reside in a target-specific numbered
818 address space. For targets that support them, address spaces may affect how
819 optimizations are performed and/or what target instructions are used to
820 access the variable. The default address space is zero. The address space
821 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]822
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]823<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]824 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]825
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]826<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]827 the alignment is set to zero, the alignment of the global is set by the
828 target to whatever it feels convenient. If an explicit alignment is
829 specified, the global is forced to have at least that much alignment. All
830 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]831
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]832<p>For example, the following defines a global in a numbered address space with
833 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]834
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]835<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]836<pre>
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]837@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]838</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]839</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]840
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]841</div>
842
843
844<!-- ======================================================================= -->
845<div class="doc_subsection">
846 <a name="functionstructure">Functions</a>
847</div>
848
849<div class="doc_text">
850
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]851<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
852 optional <a href="#linkage">linkage type</a>, an optional
853 <a href="#visibility">visibility style</a>, an optional
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) argument list (each with optional
857 <a href="#paramattrs">parameter attributes</a>), optional
858 <a href="#fnattrs">function attributes</a>, an optional section, an optional
859 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
860 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]861
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]862<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
863 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]864 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]865 <a href="#callingconv">calling convention</a>, a return type, an optional
866 <a href="#paramattrs">parameter attribute</a> for the return type, a function
867 name, a possibly empty list of arguments, an optional alignment, and an
868 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]869
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]870<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]871 (Control Flow Graph) for the function. Each basic block may optionally start
872 with a label (giving the basic block a symbol table entry), contains a list
873 of instructions, and ends with a <a href="#terminators">terminator</a>
874 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]875
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]876<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]877 executed on entrance to the function, and it is not allowed to have
878 predecessor basic blocks (i.e. there can not be any branches to the entry
879 block of a function). Because the block can have no predecessors, it also
880 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]881
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]882<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]883 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]884
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]885<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]886 the alignment is set to zero, the alignment of the function is set by the
887 target to whatever it feels convenient. If an explicit alignment is
888 specified, the function is forced to have at least that much alignment. All
889 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]890
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]891<h5>Syntax:</h5>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]892<div class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]893<pre>
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]894define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]895 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
896 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
897 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
898 [<a href="#gc">gc</a>] { ... }
899</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]900</div>
901
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]902</div>
903
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]904<!-- ======================================================================= -->
905<div class="doc_subsection">
906 <a name="aliasstructure">Aliases</a>
907</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]908
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]909<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]910
911<p>Aliases act as "second name" for the aliasee value (which can be either
912 function, global variable, another alias or bitcast of global value). Aliases
913 may have an optional <a href="#linkage">linkage type</a>, and an
914 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]915
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]916<h5>Syntax:</h5>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]917<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]918<pre>
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]919@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]920</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]921</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]922
923</div>
924
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]925<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]926<div class="doc_subsection">
927 <a name="namedmetadatastructure">Named Metadata</a>
928</div>
929
930<div class="doc_text">
931
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]932<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
933 nodes</a> (but not metadata strings) and null are the only valid operands for
934 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]935
936<h5>Syntax:</h5>
937<div class="doc_code">
938<pre>
939!1 = metadata !{metadata !"one"}
940!name = !{null, !1}
941</pre>
942</div>
943
944</div>
945
946<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]947<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]948
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]949<div class="doc_text">
950
951<p>The return type and each parameter of a function type may have a set of
952 <i>parameter attributes</i> associated with them. Parameter attributes are
953 used to communicate additional information about the result or parameters of
954 a function. Parameter attributes are considered to be part of the function,
955 not of the function type, so functions with different parameter attributes
956 can have the same function type.</p>
957
958<p>Parameter attributes are simple keywords that follow the type specified. If
959 multiple parameter attributes are needed, they are space separated. For
960 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]961
962<div class="doc_code">
963<pre>
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]964declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]965declare i32 @atoi(i8 zeroext)
966declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]967</pre>
968</div>
969
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]970<p>Note that any attributes for the function result (<tt>nounwind</tt>,
971 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]972
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]973<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]974
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]975<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]976 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]977 <dd>This indicates to the code generator that the parameter or return value
978 should be zero-extended to a 32-bit value by the caller (for a parameter)
979 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]980
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]981 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]982 <dd>This indicates to the code generator that the parameter or return value
983 should be sign-extended to a 32-bit value by the caller (for a parameter)
984 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]985
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]986 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]987 <dd>This indicates that this parameter or return value should be treated in a
988 special target-dependent fashion during while emitting code for a function
989 call or return (usually, by putting it in a register as opposed to memory,
990 though some targets use it to distinguish between two different kinds of
991 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]992
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]993 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]994 <dd>This indicates that the pointer parameter should really be passed by value
995 to the function. The attribute implies that a hidden copy of the pointee
996 is made between the caller and the callee, so the callee is unable to
997 modify the value in the callee. This attribute is only valid on LLVM
998 pointer arguments. It is generally used to pass structs and arrays by
999 value, but is also valid on pointers to scalars. The copy is considered
1000 to belong to the caller not the callee (for example,
1001 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1002 <tt>byval</tt> parameters). This is not a valid attribute for return
1003 values. The byval attribute also supports specifying an alignment with
1004 the align attribute. This has a target-specific effect on the code
1005 generator that usually indicates a desired alignment for the synthesized
1006 stack slot.</dd>
1007
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1008 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1009 <dd>This indicates that the pointer parameter specifies the address of a
1010 structure that is the return value of the function in the source program.
1011 This pointer must be guaranteed by the caller to be valid: loads and
1012 stores to the structure may be assumed by the callee to not to trap. This
1013 may only be applied to the first parameter. This is not a valid attribute
1014 for return values. </dd>
1015
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1016 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1017 <dd>This indicates that the pointer does not alias any global or any other
1018 parameter. The caller is responsible for ensuring that this is the
1019 case. On a function return value, <tt>noalias</tt> additionally indicates
1020 that the pointer does not alias any other pointers visible to the
1021 caller. For further details, please see the discussion of the NoAlias
1022 response in
1023 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1024 analysis</a>.</dd>
1025
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1026 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1027 <dd>This indicates that the callee does not make any copies of the pointer
1028 that outlive the callee itself. This is not a valid attribute for return
1029 values.</dd>
1030
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1031 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1032 <dd>This indicates that the pointer parameter can be excised using the
1033 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1034 attribute for return values.</dd>
1035</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1036
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1037</div>
1038
1039<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1040<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1041 <a name="gc">Garbage Collector Names</a>
1042</div>
1043
1044<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1045
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1046<p>Each function may specify a garbage collector name, which is simply a
1047 string:</p>
1048
1049<div class="doc_code">
1050<pre>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1051define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1052</pre>
1053</div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1054
1055<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1056 collector which will cause the compiler to alter its output in order to
1057 support the named garbage collection algorithm.</p>
1058
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1059</div>
1060
1061<!-- ======================================================================= -->
1062<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1063 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1064</div>
1065
1066<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1067
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1068<p>Function attributes are set to communicate additional information about a
1069 function. Function attributes are considered to be part of the function, not
1070 of the function type, so functions with different parameter attributes can
1071 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1072
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1073<p>Function attributes are simple keywords that follow the type specified. If
1074 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1075
1076<div class="doc_code">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1077<pre>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1078define void @f() noinline { ... }
1079define void @f() alwaysinline { ... }
1080define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1081define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1082</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1083</div>
1084
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1085<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1086 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1087 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1088 the backend should forcibly align the stack pointer. Specify the
1089 desired alignment, which must be a power of two, in parentheses.
1090
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1091 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1092 <dd>This attribute indicates that the inliner should attempt to inline this
1093 function into callers whenever possible, ignoring any active inlining size
1094 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1095
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1096 <dt><tt><b>inlinehint</b></tt></dt>
1097 <dd>This attribute indicates that the source code contained a hint that inlining
1098 this function is desirable (such as the "inline" keyword in C/C++). It
1099 is just a hint; it imposes no requirements on the inliner.</dd>
1100
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1101 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1102 <dd>This attribute indicates that the inliner should never inline this
1103 function in any situation. This attribute may not be used together with
1104 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1105
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1106 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1107 <dd>This attribute suggests that optimization passes and code generator passes
1108 make choices that keep the code size of this function low, and otherwise
1109 do optimizations specifically to reduce code size.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1110
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1111 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1112 <dd>This function attribute indicates that the function never returns
1113 normally. This produces undefined behavior at runtime if the function
1114 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1115
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1116 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1117 <dd>This function attribute indicates that the function never returns with an
1118 unwind or exceptional control flow. If the function does unwind, its
1119 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1120
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1121 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1122 <dd>This attribute indicates that the function computes its result (or decides
1123 to unwind an exception) based strictly on its arguments, without
1124 dereferencing any pointer arguments or otherwise accessing any mutable
1125 state (e.g. memory, control registers, etc) visible to caller functions.
1126 It does not write through any pointer arguments
1127 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1128 changes any state visible to callers. This means that it cannot unwind
1129 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1130 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1131
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1132 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1133 <dd>This attribute indicates that the function does not write through any
1134 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1135 arguments) or otherwise modify any state (e.g. memory, control registers,
1136 etc) visible to caller functions. It may dereference pointer arguments
1137 and read state that may be set in the caller. A readonly function always
1138 returns the same value (or unwinds an exception identically) when called
1139 with the same set of arguments and global state. It cannot unwind an
1140 exception by calling the <tt>C++</tt> exception throwing methods, but may
1141 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1142
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This attribute indicates that the function should emit a stack smashing
1145 protector. It is in the form of a "canary"&mdash;a random value placed on
1146 the stack before the local variables that's checked upon return from the
1147 function to see if it has been overwritten. A heuristic is used to
1148 determine if a function needs stack protectors or not.<br>
1149<br>
1150 If a function that has an <tt>ssp</tt> attribute is inlined into a
1151 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1152 function will have an <tt>ssp</tt> attribute.</dd>
1153
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1154 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1155 <dd>This attribute indicates that the function should <em>always</em> emit a
1156 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1157 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1158<br>
1159 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1160 function that doesn't have an <tt>sspreq</tt> attribute or which has
1161 an <tt>ssp</tt> attribute, then the resulting function will have
1162 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1163
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1164 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1165 <dd>This attribute indicates that the code generator should not use a red
1166 zone, even if the target-specific ABI normally permits it.</dd>
1167
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1168 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1169 <dd>This attributes disables implicit floating point instructions.</dd>
1170
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This attribute disables prologue / epilogue emission for the function.
1173 This can have very system-specific consequences.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1174</dl>
1175
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1176</div>
1177
1178<!-- ======================================================================= -->
1179<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1180 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1181</div>
1182
1183<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1184
1185<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1186 the GCC "file scope inline asm" blocks. These blocks are internally
1187 concatenated by LLVM and treated as a single unit, but may be separated in
1188 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1189
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1190<div class="doc_code">
1191<pre>
1192module asm "inline asm code goes here"
1193module asm "more can go here"
1194</pre>
1195</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1196
1197<p>The strings can contain any character by escaping non-printable characters.
1198 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]1199 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1200
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1201<p>The inline asm code is simply printed to the machine code .s file when
1202 assembly code is generated.</p>
1203
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1204</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1205
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1206<!-- ======================================================================= -->
1207<div class="doc_subsection">
1208 <a name="datalayout">Data Layout</a>
1209</div>
1210
1211<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1212
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1213<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1214 data is to be laid out in memory. The syntax for the data layout is
1215 simply:</p>
1216
1217<div class="doc_code">
1218<pre>
1219target datalayout = "<i>layout specification</i>"
1220</pre>
1221</div>
1222
1223<p>The <i>layout specification</i> consists of a list of specifications
1224 separated by the minus sign character ('-'). Each specification starts with
1225 a letter and may include other information after the letter to define some
1226 aspect of the data layout. The specifications accepted are as follows:</p>
1227
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1228<dl>
1229 <dt><tt>E</tt></dt>
1230 <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]1231 bits with the most significance have the lowest address location.</dd>
1232
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1233 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1234 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1235 the bits with the least significance have the lowest address
1236 location.</dd>
1237
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1238 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1239 <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]1240 <i>preferred</i> alignments. All sizes are in bits. Specifying
1241 the <i>pref</i> alignment is optional. If omitted, the
1242 preceding <tt>:</tt> should be omitted too.</dd>
1243
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1244 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1245 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1246 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1247
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1248 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1249 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1250 <i>size</i>.</dd>
1251
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1252 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1253 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1254 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1255 (double).</dd>
1256
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1257 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1258 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1259 <i>size</i>.</dd>
1260
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1261 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1262 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1263 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1264
1265 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1266 <dd>This specifies a set of native integer widths for the target CPU
1267 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1268 "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]1269 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1270 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1271</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1272
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1273<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1274 default set of specifications which are then (possibly) overriden by the
1275 specifications in the <tt>datalayout</tt> keyword. The default specifications
1276 are given in this list:</p>
1277
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1278<ul>
1279 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1280 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1281 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1282 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1283 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1284 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1285 <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]1286 alignment of 64-bits</li>
1287 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1288 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1289 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1290 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1291 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1292 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1293</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1294
1295<p>When LLVM is determining the alignment for a given type, it uses the
1296 following rules:</p>
1297
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1298<ol>
1299 <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]1300 specification is used.</li>
1301
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1302 <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]1303 smallest integer type that is larger than the bitwidth of the sought type
1304 is used. If none of the specifications are larger than the bitwidth then
1305 the the largest integer type is used. For example, given the default
1306 specifications above, the i7 type will use the alignment of i8 (next
1307 largest) while both i65 and i256 will use the alignment of i64 (largest
1308 specified).</li>
1309
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1310 <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]1311 largest vector type that is smaller than the sought vector type will be
1312 used as a fall back. This happens because &lt;128 x double&gt; can be
1313 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1314</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1315
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1316</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1317
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1318<!-- ======================================================================= -->
1319<div class="doc_subsection">
1320 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1321</div>
1322
1323<div class="doc_text">
1324
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1325<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1326with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1327is undefined. Pointer values are associated with address ranges
1328according to the following rules:</p>
1329
1330<ul>
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1331 <li>A pointer value formed from a
1332 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1333 is associated with the addresses associated with the first operand
1334 of the <tt>getelementptr</tt>.</li>
1335 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1336 range of the variable's storage.</li>
1337 <li>The result value of an allocation instruction is associated with
1338 the address range of the allocated storage.</li>
1339 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1340 no address.</li>
1341 <li>A pointer value formed by an
1342 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1343 address ranges of all pointer values that contribute (directly or
1344 indirectly) to the computation of the pointer's value.</li>
1345 <li>The result value of a
1346 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1347 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1348 <li>An integer constant other than zero or a pointer value returned
1349 from a function not defined within LLVM may be associated with address
1350 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1351 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1352 allocated by mechanisms provided by LLVM.</li>
1353 </ul>
1354
1355<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1356<tt><a href="#i_load">load</a></tt> merely indicates the size and
1357alignment of the memory from which to load, as well as the
1358interpretation of the value. The first operand of a
1359<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1360and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1361
1362<p>Consequently, type-based alias analysis, aka TBAA, aka
1363<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1364LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1365additional information which specialized optimization passes may use
1366to implement type-based alias analysis.</p>
1367
1368</div>
1369
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1370<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1371<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1372<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1373
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1374<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1375
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1376<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1377 intermediate representation. Being typed enables a number of optimizations
1378 to be performed on the intermediate representation directly, without having
1379 to do extra analyses on the side before the transformation. A strong type
1380 system makes it easier to read the generated code and enables novel analyses
1381 and transformations that are not feasible to perform on normal three address
1382 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1383
1384</div>
1385
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1386<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1387<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1388Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1389
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1390<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1391
1392<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1393
1394<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1395 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1396 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1397 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1398 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1399 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1400 </tr>
1401 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1402 <td><a href="#t_floating">floating point</a></td>
1403 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1404 </tr>
1405 <tr>
1406 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1407 <td><a href="#t_integer">integer</a>,
1408 <a href="#t_floating">floating point</a>,
1409 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1410 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1411 <a href="#t_struct">structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1412 <a href="#t_union">union</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1413 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1414 <a href="#t_label">label</a>,
1415 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1416 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1417 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1418 <tr>
1419 <td><a href="#t_primitive">primitive</a></td>
1420 <td><a href="#t_label">label</a>,
1421 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1422 <a href="#t_floating">floating point</a>,
1423 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1424 </tr>
1425 <tr>
1426 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1427 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1428 <a href="#t_function">function</a>,
1429 <a href="#t_pointer">pointer</a>,
1430 <a href="#t_struct">structure</a>,
1431 <a href="#t_pstruct">packed structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1432 <a href="#t_union">union</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1433 <a href="#t_vector">vector</a>,
1434 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1435 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1436 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1437 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1438</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1439
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1440<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1441 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1442 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1443
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1444</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1445
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1446<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1447<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1448
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1449<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1450
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1451<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1452 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1453
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1454</div>
1455
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1456<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1457<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1458
1459<div class="doc_text">
1460
1461<h5>Overview:</h5>
1462<p>The integer type is a very simple type that simply specifies an arbitrary
1463 bit width for the integer type desired. Any bit width from 1 bit to
1464 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1465
1466<h5>Syntax:</h5>
1467<pre>
1468 iN
1469</pre>
1470
1471<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1472 value.</p>
1473
1474<h5>Examples:</h5>
1475<table class="layout">
1476 <tr class="layout">
1477 <td class="left"><tt>i1</tt></td>
1478 <td class="left">a single-bit integer.</td>
1479 </tr>
1480 <tr class="layout">
1481 <td class="left"><tt>i32</tt></td>
1482 <td class="left">a 32-bit integer.</td>
1483 </tr>
1484 <tr class="layout">
1485 <td class="left"><tt>i1942652</tt></td>
1486 <td class="left">a really big integer of over 1 million bits.</td>
1487 </tr>
1488</table>
1489
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1490</div>
1491
1492<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1493<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1494
1495<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1496
1497<table>
1498 <tbody>
1499 <tr><th>Type</th><th>Description</th></tr>
1500 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1501 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1502 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1503 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1504 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1505 </tbody>
1506</table>
1507
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1508</div>
1509
1510<!-- _______________________________________________________________________ -->
1511<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1512
1513<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1514
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1515<h5>Overview:</h5>
1516<p>The void type does not represent any value and has no size.</p>
1517
1518<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1519<pre>
1520 void
1521</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1522
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1523</div>
1524
1525<!-- _______________________________________________________________________ -->
1526<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1527
1528<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1529
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1530<h5>Overview:</h5>
1531<p>The label type represents code labels.</p>
1532
1533<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1534<pre>
1535 label
1536</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1537
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1538</div>
1539
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1540<!-- _______________________________________________________________________ -->
1541<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1542
1543<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1544
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1545<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1546<p>The metadata type represents embedded metadata. No derived types may be
1547 created from metadata except for <a href="#t_function">function</a>
1548 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1549
1550<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1551<pre>
1552 metadata
1553</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1554
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1555</div>
1556
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1557
1558<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1559<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1560
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1561<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1562
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1563<p>The real power in LLVM comes from the derived types in the system. This is
1564 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1565 useful types. Each of these types contain one or more element types which
1566 may be a primitive type, or another derived type. For example, it is
1567 possible to have a two dimensional array, using an array as the element type
1568 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1569
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1570
1571</div>
1572
1573<!-- _______________________________________________________________________ -->
1574<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1575
1576<div class="doc_text">
1577
1578<p>Aggregate Types are a subset of derived types that can contain multiple
1579 member types. <a href="#t_array">Arrays</a>,
1580 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1581 <a href="#t_union">unions</a> are aggregate types.</p>
1582
1583</div>
1584
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1585</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1586
1587<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1588<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1589
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1590<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1591
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1592<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1593<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1594 sequentially in memory. The array type requires a size (number of elements)
1595 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1596
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1597<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1598<pre>
1599 [&lt;# elements&gt; x &lt;elementtype&gt;]
1600</pre>
1601
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1602<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1603 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1604
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1605<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1606<table class="layout">
1607 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1608 <td class="left"><tt>[40 x i32]</tt></td>
1609 <td class="left">Array of 40 32-bit integer values.</td>
1610 </tr>
1611 <tr class="layout">
1612 <td class="left"><tt>[41 x i32]</tt></td>
1613 <td class="left">Array of 41 32-bit integer values.</td>
1614 </tr>
1615 <tr class="layout">
1616 <td class="left"><tt>[4 x i8]</tt></td>
1617 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1618 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1619</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1620<p>Here are some examples of multidimensional arrays:</p>
1621<table class="layout">
1622 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1623 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1624 <td class="left">3x4 array of 32-bit integer values.</td>
1625 </tr>
1626 <tr class="layout">
1627 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1628 <td class="left">12x10 array of single precision floating point values.</td>
1629 </tr>
1630 <tr class="layout">
1631 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1632 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1633 </tr>
1634</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1635
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1636<p>There is no restriction on indexing beyond the end of the array implied by
1637 a static type (though there are restrictions on indexing beyond the bounds
1638 of an allocated object in some cases). This means that single-dimension
1639 'variable sized array' addressing can be implemented in LLVM with a zero
1640 length array type. An implementation of 'pascal style arrays' in LLVM could
1641 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1642
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1643</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1644
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1645<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1646<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1647
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1648<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1649
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1650<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1651<p>The function type can be thought of as a function signature. It consists of
1652 a return type and a list of formal parameter types. The return type of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1653 function type is a scalar type, a void type, a struct type, or a union
1654 type. If the return type is a struct type then all struct elements must be
1655 of first class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1656
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1657<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1658<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1659 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1660</pre>
1661
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1662<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]1663 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1664 which indicates that the function takes a variable number of arguments.
1665 Variable argument functions can access their arguments with
1666 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1667 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1668 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +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">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1673 <td class="left"><tt>i32 (i32)</tt></td>
1674 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1675 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1676 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1677 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1678 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1679 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1680 an <tt>i16</tt> that should be sign extended and a
1681 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1682 <tt>float</tt>.
1683 </td>
1684 </tr><tr class="layout">
1685 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1686 <td class="left">A vararg function that takes at least one
1687 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1688 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1689 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1690 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1691 </tr><tr class="layout">
1692 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1693 <td class="left">A function taking an <tt>i32</tt>, returning a
1694 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1695 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1696 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1697</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1698
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1699</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1700
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1701<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1702<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1703
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1704<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1705
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1706<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1707<p>The structure type is used to represent a collection of data members together
1708 in memory. The packing of the field types is defined to match the ABI of the
1709 underlying processor. The elements of a structure may be any type that has a
1710 size.</p>
1711
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1712<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1713 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1714 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1715 Structures in registers are accessed using the
1716 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1717 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1718<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1719<pre>
1720 { &lt;type list&gt; }
1721</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1722
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1723<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1724<table class="layout">
1725 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1726 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1727 <td class="left">A triple of three <tt>i32</tt> values</td>
1728 </tr><tr class="layout">
1729 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1730 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1731 second element is a <a href="#t_pointer">pointer</a> to a
1732 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1733 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1734 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1735</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1736
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1737</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1738
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1739<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1740<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1741</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1742
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1743<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1744
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1745<h5>Overview:</h5>
1746<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1747 together in memory. There is no padding between fields. Further, the
1748 alignment of a packed structure is 1 byte. The elements of a packed
1749 structure may be any type that has a size.</p>
1750
1751<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1752 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1753 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1754
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1755<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1756<pre>
1757 &lt; { &lt;type list&gt; } &gt;
1758</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1759
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1760<h5>Examples:</h5>
1761<table class="layout">
1762 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1763 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1764 <td class="left">A triple of three <tt>i32</tt> values</td>
1765 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1766 <td class="left">
1767<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1768 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1769 second element is a <a href="#t_pointer">pointer</a> to a
1770 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1771 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1772 </tr>
1773</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1774
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1775</div>
1776
1777<!-- _______________________________________________________________________ -->
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1778<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1779
1780<div class="doc_text">
1781
1782<h5>Overview:</h5>
1783<p>A union type describes an object with size and alignment suitable for
1784 an object of any one of a given set of types (also known as an "untagged"
1785 union). It is similar in concept and usage to a
1786 <a href="#t_struct">struct</a>, except that all members of the union
1787 have an offset of zero. The elements of a union may be any type that has a
1788 size. Unions must have at least one member - empty unions are not allowed.
1789 </p>
1790
1791<p>The size of the union as a whole will be the size of its largest member,
1792 and the alignment requirements of the union as a whole will be the largest
1793 alignment requirement of any member.</p>
1794
Dan Gohman1ad14992010-02-25 16:51:31 +0000[diff] [blame^]1795<p>Union members are accessed using '<tt><a href="#i_load">load</a></tt> and
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1796 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1797 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1798 Since all members are at offset zero, the getelementptr instruction does
1799 not affect the address, only the type of the resulting pointer.</p>
1800
1801<h5>Syntax:</h5>
1802<pre>
1803 union { &lt;type list&gt; }
1804</pre>
1805
1806<h5>Examples:</h5>
1807<table class="layout">
1808 <tr class="layout">
1809 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1810 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1811 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1812 </tr><tr class="layout">
1813 <td class="left">
1814 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1815 <td class="left">A union, where the first element is a <tt>float</tt> and the
1816 second element is a <a href="#t_pointer">pointer</a> to a
1817 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1818 an <tt>i32</tt>.</td>
1819 </tr>
1820</table>
1821
1822</div>
1823
1824<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1825<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1826
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1827<div class="doc_text">
1828
1829<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1830<p>The pointer type is used to specify memory locations.
1831 Pointers are commonly used to reference objects in memory.</p>
1832
1833<p>Pointer types may have an optional address space attribute defining the
1834 numbered address space where the pointed-to object resides. The default
1835 address space is number zero. The semantics of non-zero address
1836 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1837
1838<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1839 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1840
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1841<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1842<pre>
1843 &lt;type&gt; *
1844</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1845
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1846<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1847<table class="layout">
1848 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1849 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1850 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1851 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1852 </tr>
1853 <tr class="layout">
1854 <td class="left"><tt>i32 (i32 *) *</tt></td>
1855 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1856 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1857 <tt>i32</tt>.</td>
1858 </tr>
1859 <tr class="layout">
1860 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1861 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1862 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1863 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1864</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1865
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1866</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1867
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1868<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1869<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1870
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1871<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1872
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1873<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1874<p>A vector type is a simple derived type that represents a vector of elements.
1875 Vector types are used when multiple primitive data are operated in parallel
1876 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1877 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1878 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1879
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1880<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1881<pre>
1882 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1883</pre>
1884
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1885<p>The number of elements is a constant integer value; elementtype may be any
1886 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1887
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1888<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1889<table class="layout">
1890 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1891 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1892 <td class="left">Vector of 4 32-bit integer values.</td>
1893 </tr>
1894 <tr class="layout">
1895 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1896 <td class="left">Vector of 8 32-bit floating-point values.</td>
1897 </tr>
1898 <tr class="layout">
1899 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1900 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1901 </tr>
1902</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1903
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1904</div>
1905
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1906<!-- _______________________________________________________________________ -->
1907<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1908<div class="doc_text">
1909
1910<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1911<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1912 corresponds (for example) to the C notion of a forward declared structure
1913 type. In LLVM, opaque types can eventually be resolved to any type (not just
1914 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1915
1916<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1917<pre>
1918 opaque
1919</pre>
1920
1921<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1922<table class="layout">
1923 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1924 <td class="left"><tt>opaque</tt></td>
1925 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1926 </tr>
1927</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1928
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1929</div>
1930
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1931<!-- ======================================================================= -->
1932<div class="doc_subsection">
1933 <a name="t_uprefs">Type Up-references</a>
1934</div>
1935
1936<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1937
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1938<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1939<p>An "up reference" allows you to refer to a lexically enclosing type without
1940 requiring it to have a name. For instance, a structure declaration may
1941 contain a pointer to any of the types it is lexically a member of. Example
1942 of up references (with their equivalent as named type declarations)
1943 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1944
1945<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1946 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1947 { \2 }* %y = type { %y }*
1948 \1* %z = type %z*
1949</pre>
1950
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1951<p>An up reference is needed by the asmprinter for printing out cyclic types
1952 when there is no declared name for a type in the cycle. Because the
1953 asmprinter does not want to print out an infinite type string, it needs a
1954 syntax to handle recursive types that have no names (all names are optional
1955 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1956
1957<h5>Syntax:</h5>
1958<pre>
1959 \&lt;level&gt;
1960</pre>
1961
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1962<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]1963
1964<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1965<table class="layout">
1966 <tr class="layout">
1967 <td class="left"><tt>\1*</tt></td>
1968 <td class="left">Self-referential pointer.</td>
1969 </tr>
1970 <tr class="layout">
1971 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1972 <td class="left">Recursive structure where the upref refers to the out-most
1973 structure.</td>
1974 </tr>
1975</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1976
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1977</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1978
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1979<!-- *********************************************************************** -->
1980<div class="doc_section"> <a name="constants">Constants</a> </div>
1981<!-- *********************************************************************** -->
1982
1983<div class="doc_text">
1984
1985<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1986 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1987
1988</div>
1989
1990<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1991<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1992
1993<div class="doc_text">
1994
1995<dl>
1996 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1997 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1998 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1999
2000 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2001 <dd>Standard integers (such as '4') are constants of
2002 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2003 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2004
2005 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2006 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2007 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2008 notation (see below). The assembler requires the exact decimal value of a
2009 floating-point constant. For example, the assembler accepts 1.25 but
2010 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2011 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2012
2013 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2014 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2015 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2016</dl>
2017
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2018<p>The one non-intuitive notation for constants is the hexadecimal form of
2019 floating point constants. For example, the form '<tt>double
2020 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2021 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2022 constants are required (and the only time that they are generated by the
2023 disassembler) is when a floating point constant must be emitted but it cannot
2024 be represented as a decimal floating point number in a reasonable number of
2025 digits. For example, NaN's, infinities, and other special values are
2026 represented in their IEEE hexadecimal format so that assembly and disassembly
2027 do not cause any bits to change in the constants.</p>
2028
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2029<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2030 represented using the 16-digit form shown above (which matches the IEEE754
2031 representation for double); float values must, however, be exactly
2032 representable as IEE754 single precision. Hexadecimal format is always used
2033 for long double, and there are three forms of long double. The 80-bit format
2034 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2035 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2036 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2037 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2038 currently supported target uses this format. Long doubles will only work if
2039 they match the long double format on your target. All hexadecimal formats
2040 are big-endian (sign bit at the left).</p>
2041
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2042</div>
2043
2044<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2045<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2046<a name="aggregateconstants"></a> <!-- old anchor -->
2047<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2048</div>
2049
2050<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2051
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2052<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2053 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2054
2055<dl>
2056 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2057 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2058 type definitions (a comma separated list of elements, surrounded by braces
2059 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2060 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2061 Structure constants must have <a href="#t_struct">structure type</a>, and
2062 the number and types of elements must match those specified by the
2063 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2064
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2065 <dt><b>Union constants</b></dt>
2066 <dd>Union constants are represented with notation similar to a structure with
2067 a single element - that is, a single typed element surrounded
2068 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2069 <a href="#t_union">union type</a> can be initialized with a single-element
2070 struct as long as the type of the struct element matches the type of
2071 one of the union members.</dd>
2072
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2073 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2074 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2075 definitions (a comma separated list of elements, surrounded by square
2076 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2077 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2078 the number and types of elements must match those specified by the
2079 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2080
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2081 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2082 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2083 definitions (a comma separated list of elements, surrounded by
2084 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2085 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2086 have <a href="#t_vector">vector type</a>, and the number and types of
2087 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2088
2089 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2090 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2091 value to zero of <em>any</em> type, including scalar and
2092 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2093 This is often used to avoid having to print large zero initializers
2094 (e.g. for large arrays) and is always exactly equivalent to using explicit
2095 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2096
2097 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2098 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2099 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2100 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2101 be interpreted as part of the instruction stream, metadata is a place to
2102 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2103</dl>
2104
2105</div>
2106
2107<!-- ======================================================================= -->
2108<div class="doc_subsection">
2109 <a name="globalconstants">Global Variable and Function Addresses</a>
2110</div>
2111
2112<div class="doc_text">
2113
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2114<p>The addresses of <a href="#globalvars">global variables</a>
2115 and <a href="#functionstructure">functions</a> are always implicitly valid
2116 (link-time) constants. These constants are explicitly referenced when
2117 the <a href="#identifiers">identifier for the global</a> is used and always
2118 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2119 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2120
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2121<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2122<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2123@X = global i32 17
2124@Y = global i32 42
2125@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2126</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2127</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2128
2129</div>
2130
2131<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2132<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2133<div class="doc_text">
2134
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2135<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]2136 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2137 Undefined values may be of any type (other than label or void) and be used
2138 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2139
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2140<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2141 program is well defined no matter what value is used. This gives the
2142 compiler more freedom to optimize. Here are some examples of (potentially
2143 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2144
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2145
2146<div class="doc_code">
2147<pre>
2148 %A = add %X, undef
2149 %B = sub %X, undef
2150 %C = xor %X, undef
2151Safe:
2152 %A = undef
2153 %B = undef
2154 %C = undef
2155</pre>
2156</div>
2157
2158<p>This is safe because all of the output bits are affected by the undef bits.
2159Any output bit can have a zero or one depending on the input bits.</p>
2160
2161<div class="doc_code">
2162<pre>
2163 %A = or %X, undef
2164 %B = and %X, undef
2165Safe:
2166 %A = -1
2167 %B = 0
2168Unsafe:
2169 %A = undef
2170 %B = undef
2171</pre>
2172</div>
2173
2174<p>These logical operations have bits that are not always affected by the input.
2175For example, if "%X" has a zero bit, then the output of the 'and' operation will
2176always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2177such, 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]2178However, it is safe to assume that all bits of the undef could be 0, and
2179optimize the and to 0. Likewise, it is safe to assume that all the bits of
2180the 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]2181-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2182
2183<div class="doc_code">
2184<pre>
2185 %A = select undef, %X, %Y
2186 %B = select undef, 42, %Y
2187 %C = select %X, %Y, undef
2188Safe:
2189 %A = %X (or %Y)
2190 %B = 42 (or %Y)
2191 %C = %Y
2192Unsafe:
2193 %A = undef
2194 %B = undef
2195 %C = undef
2196</pre>
2197</div>
2198
2199<p>This set of examples show that undefined select (and conditional branch)
2200conditions can go "either way" but they have to come from one of the two
2201operands. In the %A example, if %X and %Y were both known to have a clear low
2202bit, then %A would have to have a cleared low bit. However, in the %C example,
2203the optimizer is allowed to assume that the undef operand could be the same as
2204%Y, allowing the whole select to be eliminated.</p>
2205
2206
2207<div class="doc_code">
2208<pre>
2209 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2210
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2211 %B = undef
2212 %C = xor %B, %B
2213
2214 %D = undef
2215 %E = icmp lt %D, 4
2216 %F = icmp gte %D, 4
2217
2218Safe:
2219 %A = undef
2220 %B = undef
2221 %C = undef
2222 %D = undef
2223 %E = undef
2224 %F = undef
2225</pre>
2226</div>
2227
2228<p>This example points out that two undef operands are not necessarily the same.
2229This can be surprising to people (and also matches C semantics) where they
2230assume that "X^X" is always zero, even if X is undef. This isn't true for a
2231number of reasons, but the short answer is that an undef "variable" can
2232arbitrarily change its value over its "live range". This is true because the
2233"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2234logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2235so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2236to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2237would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2238
2239<div class="doc_code">
2240<pre>
2241 %A = fdiv undef, %X
2242 %B = fdiv %X, undef
2243Safe:
2244 %A = undef
2245b: unreachable
2246</pre>
2247</div>
2248
2249<p>These examples show the crucial difference between an <em>undefined
2250value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2251allowed to have an arbitrary bit-pattern. This means that the %A operation
2252can be constant folded to undef because the undef could be an SNaN, and fdiv is
2253not (currently) defined on SNaN's. However, in the second example, we can make
2254a more aggressive assumption: because the undef is allowed to be an arbitrary
2255value, 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]2256has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2257does not execute at all. This allows us to delete the divide and all code after
2258it: since the undefined operation "can't happen", the optimizer can assume that
2259it occurs in dead code.
2260</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2261
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2262<div class="doc_code">
2263<pre>
2264a: store undef -> %X
2265b: store %X -> undef
2266Safe:
2267a: &lt;deleted&gt;
2268b: unreachable
2269</pre>
2270</div>
2271
2272<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2273can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2274overwritten with bits that happen to match what was already there. However, a
2275store "to" an undefined location could clobber arbitrary memory, therefore, it
2276has undefined behavior.</p>
2277
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2278</div>
2279
2280<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2281<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2282 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2283<div class="doc_text">
2284
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2285<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2286
2287<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2288 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2289 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2290
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2291<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2292 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2293 against null. Pointer equality tests between labels addresses is undefined
2294 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2295 equal to the null pointer. This may also be passed around as an opaque
2296 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2297 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2298 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2299
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2300<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2301 using the value as the operand to an inline assembly, but that is target
2302 specific.
2303 </p>
2304
2305</div>
2306
2307
2308<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2309<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2310</div>
2311
2312<div class="doc_text">
2313
2314<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2315 to be used as constants. Constant expressions may be of
2316 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2317 operation that does not have side effects (e.g. load and call are not
2318 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2319
2320<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2321 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2322 <dd>Truncate a constant to another type. The bit size of CST must be larger
2323 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2324
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2325 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2326 <dd>Zero extend a constant to another type. The bit size of CST must be
2327 smaller or equal to the bit size of TYPE. Both types must be
2328 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2329
2330 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2331 <dd>Sign extend a constant to another type. The bit size of CST must be
2332 smaller or equal to the bit size of TYPE. Both types must be
2333 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2334
2335 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2336 <dd>Truncate a floating point constant to another floating point type. The
2337 size of CST must be larger than the size of TYPE. Both types must be
2338 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2339
2340 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2341 <dd>Floating point extend a constant to another type. The size of CST must be
2342 smaller or equal to the size of TYPE. Both types must be floating
2343 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2344
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]2345 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2346 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2347 constant. TYPE must be a scalar or vector integer type. CST must be of
2348 scalar or vector floating point type. Both CST and TYPE must be scalars,
2349 or vectors of the same number of elements. If the value won't fit in the
2350 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2351
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2352 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2353 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2354 constant. TYPE must be a scalar or vector integer type. CST must be of
2355 scalar or vector floating point type. Both CST and TYPE must be scalars,
2356 or vectors of the same number of elements. If the value won't fit in the
2357 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2358
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2359 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2360 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2361 constant. TYPE must be a scalar or vector floating point type. CST must be
2362 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2363 vectors of the same number of elements. If the value won't fit in the
2364 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2365
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2366 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2367 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2368 constant. TYPE must be a scalar or vector floating point type. CST must be
2369 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2370 vectors of the same number of elements. If the value won't fit in the
2371 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2372
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2373 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2374 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2375 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2376 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2377 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2378
2379 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2380 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2381 type. CST must be of integer type. The CST value is zero extended,
2382 truncated, or unchanged to make it fit in a pointer size. This one is
2383 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2384
2385 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2386 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2387 are the same as those for the <a href="#i_bitcast">bitcast
2388 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2389
2390 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]2391 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2392 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2393 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2394 instruction, the index list may have zero or more indexes, which are
2395 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2396
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2397 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2398 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2399
2400 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2401 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2402
2403 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2404 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2405
2406 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2407 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2408 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2409
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]2410 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2411 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2412 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2413
2414 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2415 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2416 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2417
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2418 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2419 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2420 be any of the <a href="#binaryops">binary</a>
2421 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2422 on operands are the same as those for the corresponding instruction
2423 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2424</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2425
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2426</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2427
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2428<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2429<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2430<!-- *********************************************************************** -->
2431
2432<!-- ======================================================================= -->
2433<div class="doc_subsection">
2434<a name="inlineasm">Inline Assembler Expressions</a>
2435</div>
2436
2437<div class="doc_text">
2438
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2439<p>LLVM supports inline assembler expressions (as opposed
2440 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2441 a special value. This value represents the inline assembler as a string
2442 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2443 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2444 expression has side effects, and a flag indicating whether the function
2445 containing the asm needs to align its stack conservatively. An example
2446 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2447
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2448<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2449<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2450i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2451</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2452</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2453
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2454<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2455 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2456 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2457
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2458<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2459<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2460%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]2461</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2462</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2463
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2464<p>Inline asms with side effects not visible in the constraint list must be
2465 marked as having side effects. This is done through the use of the
2466 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2467
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2468<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2469<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2470call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2471</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2472</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2473
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2474<p>In some cases inline asms will contain code that will not work unless the
2475 stack is aligned in some way, such as calls or SSE instructions on x86,
2476 yet will not contain code that does that alignment within the asm.
2477 The compiler should make conservative assumptions about what the asm might
2478 contain and should generate its usual stack alignment code in the prologue
2479 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2480
2481<div class="doc_code">
2482<pre>
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2483call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2484</pre>
2485</div>
2486
2487<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2488 first.</p>
2489
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2490<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2491 documented here. Constraints on what can be done (e.g. duplication, moving,
2492 etc need to be documented). This is probably best done by reference to
2493 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2494
2495</div>
2496
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2497<!-- ======================================================================= -->
2498<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2499 Strings</a>
2500</div>
2501
2502<div class="doc_text">
2503
2504<p>LLVM IR allows metadata to be attached to instructions in the program that
2505 can convey extra information about the code to the optimizers and code
2506 generator. One example application of metadata is source-level debug
2507 information. There are two metadata primitives: strings and nodes. All
2508 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2509 preceding exclamation point ('<tt>!</tt>').</p>
2510
2511<p>A metadata string is a string surrounded by double quotes. It can contain
2512 any character by escaping non-printable characters with "\xx" where "xx" is
2513 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2514
2515<p>Metadata nodes are represented with notation similar to structure constants
2516 (a comma separated list of elements, surrounded by braces and preceded by an
2517 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2518 10}</tt>". Metadata nodes can have any values as their operand.</p>
2519
2520<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2521 metadata nodes, which can be looked up in the module symbol table. For
2522 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2523
2524</div>
2525
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2526
2527<!-- *********************************************************************** -->
2528<div class="doc_section">
2529 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2530</div>
2531<!-- *********************************************************************** -->
2532
2533<p>LLVM has a number of "magic" global variables that contain data that affect
2534code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2535of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2536section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2537by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2538
2539<!-- ======================================================================= -->
2540<div class="doc_subsection">
2541<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2542</div>
2543
2544<div class="doc_text">
2545
2546<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2547href="#linkage_appending">appending linkage</a>. This array contains a list of
2548pointers to global variables and functions which may optionally have a pointer
2549cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2550
2551<pre>
2552 @X = global i8 4
2553 @Y = global i32 123
2554
2555 @llvm.used = appending global [2 x i8*] [
2556 i8* @X,
2557 i8* bitcast (i32* @Y to i8*)
2558 ], section "llvm.metadata"
2559</pre>
2560
2561<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2562compiler, assembler, and linker are required to treat the symbol as if there is
2563a reference to the global that it cannot see. For example, if a variable has
2564internal linkage and no references other than that from the <tt>@llvm.used</tt>
2565list, it cannot be deleted. This is commonly used to represent references from
2566inline asms and other things the compiler cannot "see", and corresponds to
2567"attribute((used))" in GNU C.</p>
2568
2569<p>On some targets, the code generator must emit a directive to the assembler or
2570object file to prevent the assembler and linker from molesting the symbol.</p>
2571
2572</div>
2573
2574<!-- ======================================================================= -->
2575<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2576<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2577</div>
2578
2579<div class="doc_text">
2580
2581<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2582<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2583touching the symbol. On targets that support it, this allows an intelligent
2584linker to optimize references to the symbol without being impeded as it would be
2585by <tt>@llvm.used</tt>.</p>
2586
2587<p>This is a rare construct that should only be used in rare circumstances, and
2588should not be exposed to source languages.</p>
2589
2590</div>
2591
2592<!-- ======================================================================= -->
2593<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2594<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2595</div>
2596
2597<div class="doc_text">
2598
2599<p>TODO: Describe this.</p>
2600
2601</div>
2602
2603<!-- ======================================================================= -->
2604<div class="doc_subsection">
2605<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2606</div>
2607
2608<div class="doc_text">
2609
2610<p>TODO: Describe this.</p>
2611
2612</div>
2613
2614
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2615<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2616<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2617<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2618
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2619<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2620
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2621<p>The LLVM instruction set consists of several different classifications of
2622 instructions: <a href="#terminators">terminator
2623 instructions</a>, <a href="#binaryops">binary instructions</a>,
2624 <a href="#bitwiseops">bitwise binary instructions</a>,
2625 <a href="#memoryops">memory instructions</a>, and
2626 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2627
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2628</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2629
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2630<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2631<div class="doc_subsection"> <a name="terminators">Terminator
2632Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2633
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2634<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2635
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2636<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2637 in a program ends with a "Terminator" instruction, which indicates which
2638 block should be executed after the current block is finished. These
2639 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2640 control flow, not values (the one exception being the
2641 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2642
2643<p>There are six different terminator instructions: the
2644 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2645 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2646 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2647 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2648 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2649 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2650 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2651
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2652</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2653
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2654<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2655<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2656Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2657
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2658<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2659
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2660<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2661<pre>
2662 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]2663 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2664</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2665
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2666<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2667<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2668 a value) from a function back to the caller.</p>
2669
2670<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2671 value and then causes control flow, and one that just causes control flow to
2672 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2673
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2674<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2675<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2676 return value. The type of the return value must be a
2677 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2678
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2679<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2680 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2681 value or a return value with a type that does not match its type, or if it
2682 has a void return type and contains a '<tt>ret</tt>' instruction with a
2683 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2684
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2685<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2686<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2687 the calling function's context. If the caller is a
2688 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2689 instruction after the call. If the caller was an
2690 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2691 the beginning of the "normal" destination block. If the instruction returns
2692 a value, that value shall set the call or invoke instruction's return
2693 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2694
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2695<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2696<pre>
2697 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2698 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2699 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]2700</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2701
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2702</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2703<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2704<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2705
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2706<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2707
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2708<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2709<pre>
2710 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]2711</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2712
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2713<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2714<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2715 different basic block in the current function. There are two forms of this
2716 instruction, corresponding to a conditional branch and an unconditional
2717 branch.</p>
2718
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2719<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2720<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2721 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2722 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2723 target.</p>
2724
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2725<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2726<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2727 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2728 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2729 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2730
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2731<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2732<pre>
2733Test:
2734 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2735 br i1 %cond, label %IfEqual, label %IfUnequal
2736IfEqual:
2737 <a href="#i_ret">ret</a> i32 1
2738IfUnequal:
2739 <a href="#i_ret">ret</a> i32 0
2740</pre>
2741
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2742</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2743
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2744<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2745<div class="doc_subsubsection">
2746 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2747</div>
2748
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2749<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2750
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2751<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2752<pre>
2753 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2754</pre>
2755
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2756<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2757<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]2758 several different places. It is a generalization of the '<tt>br</tt>'
2759 instruction, allowing a branch to occur to one of many possible
2760 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2761
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2762<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2763<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2764 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2765 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2766 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2767
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2768<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2769<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2770 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2771 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2772 transferred to the corresponding destination; otherwise, control flow is
2773 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2774
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2775<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2776<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2777 <tt>switch</tt> instruction, this instruction may be code generated in
2778 different ways. For example, it could be generated as a series of chained
2779 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2780
2781<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2782<pre>
2783 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2784 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2785 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2786
2787 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2788 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2789
2790 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2791 switch i32 %val, label %otherwise [ i32 0, label %onzero
2792 i32 1, label %onone
2793 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2794</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2795
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2796</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2797
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2798
2799<!-- _______________________________________________________________________ -->
2800<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2801 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2802</div>
2803
2804<div class="doc_text">
2805
2806<h5>Syntax:</h5>
2807<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2808 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]2809</pre>
2810
2811<h5>Overview:</h5>
2812
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2813<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2814 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2815 "<tt>address</tt>". Address must be derived from a <a
2816 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2817
2818<h5>Arguments:</h5>
2819
2820<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2821 rest of the arguments indicate the full set of possible destinations that the
2822 address may point to. Blocks are allowed to occur multiple times in the
2823 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2824
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2825<p>This destination list is required so that dataflow analysis has an accurate
2826 understanding of the CFG.</p>
2827
2828<h5>Semantics:</h5>
2829
2830<p>Control transfers to the block specified in the address argument. All
2831 possible destination blocks must be listed in the label list, otherwise this
2832 instruction has undefined behavior. This implies that jumps to labels
2833 defined in other functions have undefined behavior as well.</p>
2834
2835<h5>Implementation:</h5>
2836
2837<p>This is typically implemented with a jump through a register.</p>
2838
2839<h5>Example:</h5>
2840<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2841 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2842</pre>
2843
2844</div>
2845
2846
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2847<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2848<div class="doc_subsubsection">
2849 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2850</div>
2851
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2852<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2853
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2854<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2855<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2856 &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]2857 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2858</pre>
2859
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2860<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2861<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2862 function, with the possibility of control flow transfer to either the
2863 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2864 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2865 control flow will return to the "normal" label. If the callee (or any
2866 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2867 instruction, control is interrupted and continued at the dynamically nearest
2868 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2869
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2870<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2871<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2872
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2873<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2874 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2875 convention</a> the call should use. If none is specified, the call
2876 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2877
2878 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2879 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2880 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2881
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2882 <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]2883 function value being invoked. In most cases, this is a direct function
2884 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2885 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2886
2887 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2888 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2889
2890 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2891 signature argument types. If the function signature indicates the
2892 function accepts a variable number of arguments, the extra arguments can
2893 be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2894
2895 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2896 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2897
2898 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2899 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2900
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2901 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2902 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2903 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2904</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2905
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2906<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2907<p>This instruction is designed to operate as a standard
2908 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2909 primary difference is that it establishes an association with a label, which
2910 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2911
2912<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2913 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2914 exception. Additionally, this is important for implementation of
2915 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2916
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2917<p>For the purposes of the SSA form, the definition of the value returned by the
2918 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2919 block to the "normal" label. If the callee unwinds then no return value is
2920 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]2921
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]2922<p>Note that the code generator does not yet completely support unwind, and
2923that the invoke/unwind semantics are likely to change in future versions.</p>
2924
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2925<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2926<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2927 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2928 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2929 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2930 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2931</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2932
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2933</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2934
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2935<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2936
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2937<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2938Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2939
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2940<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2941
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2942<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2943<pre>
2944 unwind
2945</pre>
2946
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2947<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2948<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2949 at the first callee in the dynamic call stack which used
2950 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2951 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2952
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2953<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2954<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2955 immediately halt. The dynamic call stack is then searched for the
2956 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2957 Once found, execution continues at the "exceptional" destination block
2958 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2959 instruction in the dynamic call chain, undefined behavior results.</p>
2960
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]2961<p>Note that the code generator does not yet completely support unwind, and
2962that the invoke/unwind semantics are likely to change in future versions.</p>
2963
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2964</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2965
2966<!-- _______________________________________________________________________ -->
2967
2968<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2969Instruction</a> </div>
2970
2971<div class="doc_text">
2972
2973<h5>Syntax:</h5>
2974<pre>
2975 unreachable
2976</pre>
2977
2978<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2979<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2980 instruction is used to inform the optimizer that a particular portion of the
2981 code is not reachable. This can be used to indicate that the code after a
2982 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2983
2984<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2985<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2986
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2987</div>
2988
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2989<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2990<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2991
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2992<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2993
2994<p>Binary operators are used to do most of the computation in a program. They
2995 require two operands of the same type, execute an operation on them, and
2996 produce a single value. The operands might represent multiple data, as is
2997 the case with the <a href="#t_vector">vector</a> data type. The result value
2998 has the same type as its operands.</p>
2999
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3000<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3001
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3002</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3003
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3004<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3005<div class="doc_subsubsection">
3006 <a name="i_add">'<tt>add</tt>' Instruction</a>
3007</div>
3008
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3009<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3010
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3011<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3012<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3013 &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]3014 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3015 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3016 &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]3017</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3018
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3019<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3020<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3021
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3022<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3023<p>The two arguments to the '<tt>add</tt>' instruction must
3024 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3025 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3026
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3027<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3028<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3029
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3030<p>If the sum has unsigned overflow, the result returned is the mathematical
3031 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]3032
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3033<p>Because LLVM integers use a two's complement representation, this instruction
3034 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3035
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3036<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3037 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3038 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
3039 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3040
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3041<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3042<pre>
3043 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3044</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3045
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3046</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3047
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3048<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3049<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3050 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3051</div>
3052
3053<div class="doc_text">
3054
3055<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3056<pre>
3057 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3058</pre>
3059
3060<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3061<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3062
3063<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3064<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3065 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3066 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3067
3068<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3069<p>The value produced is the floating point sum of the two operands.</p>
3070
3071<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3072<pre>
3073 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3074</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3075
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3076</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3077
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3078<!-- _______________________________________________________________________ -->
3079<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3080 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3081</div>
3082
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3083<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3084
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3085<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3086<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3087 &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]3088 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3089 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3090 &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]3091</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3092
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3093<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3094<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3095 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3096
3097<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3098 '<tt>neg</tt>' instruction present in most other intermediate
3099 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3100
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3101<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3102<p>The two arguments to the '<tt>sub</tt>' instruction must
3103 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3104 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3105
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3106<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3107<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3108
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3109<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3110 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3111 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3112
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3113<p>Because LLVM integers use a two's complement representation, this instruction
3114 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3115
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3116<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3117 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3118 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3119 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3120
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3121<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3122<pre>
3123 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3124 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3125</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3126
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3127</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3128
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3129<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3130<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3131 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3132</div>
3133
3134<div class="doc_text">
3135
3136<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3137<pre>
3138 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3139</pre>
3140
3141<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3142<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3143 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3144
3145<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3146 '<tt>fneg</tt>' instruction present in most other intermediate
3147 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3148
3149<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3150<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3151 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3152 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3153
3154<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3155<p>The value produced is the floating point difference of the two operands.</p>
3156
3157<h5>Example:</h5>
3158<pre>
3159 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3160 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3161</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3162
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3163</div>
3164
3165<!-- _______________________________________________________________________ -->
3166<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3167 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3168</div>
3169
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3170<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3171
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3172<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3173<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3174 &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]3175 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3176 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3177 &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]3178</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3179
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3180<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3181<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3182
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3183<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3184<p>The two arguments to the '<tt>mul</tt>' instruction must
3185 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3186 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3187
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3188<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3189<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3190
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3191<p>If the result of the multiplication has unsigned overflow, the result
3192 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3193 width of the result.</p>
3194
3195<p>Because LLVM integers use a two's complement representation, and the result
3196 is the same width as the operands, this instruction returns the correct
3197 result for both signed and unsigned integers. If a full product
3198 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3199 be sign-extended or zero-extended as appropriate to the width of the full
3200 product.</p>
3201
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3202<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3203 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3204 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3205 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3206
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3207<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3208<pre>
3209 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3210</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3211
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3212</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3213
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3214<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3215<div class="doc_subsubsection">
3216 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3217</div>
3218
3219<div class="doc_text">
3220
3221<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3222<pre>
3223 &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]3224</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3225
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3226<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3227<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3228
3229<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3230<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3231 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3232 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3233
3234<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3235<p>The value produced is the floating point product of the two operands.</p>
3236
3237<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3238<pre>
3239 &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]3240</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3241
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3242</div>
3243
3244<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3245<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3246</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3247
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3248<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3249
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3250<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3251<pre>
3252 &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]3253</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3254
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3255<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3256<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3257
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3258<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3259<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3260 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3261 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3262
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3263<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3264<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3265
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3266<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3267 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3268
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3269<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3270
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3271<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3272<pre>
3273 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3274</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3275
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3276</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3277
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3278<!-- _______________________________________________________________________ -->
3279<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3280</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3281
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3282<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3283
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3284<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3285<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3286 &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]3287 &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]3288</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3289
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3290<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3291<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3292
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3293<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3294<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3295 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3296 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3297
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3298<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3299<p>The value produced is the signed integer quotient of the two operands rounded
3300 towards zero.</p>
3301
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3302<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3303 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3304
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3305<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3306 undefined behavior; this is a rare case, but can occur, for example, by doing
3307 a 32-bit division of -2147483648 by -1.</p>
3308
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3309<p>If the <tt>exact</tt> keyword is present, the result value of the
3310 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3311 would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3312
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3313<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3314<pre>
3315 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3316</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3317
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3318</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3319
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3320<!-- _______________________________________________________________________ -->
3321<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3322Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3323
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3324<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3325
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3326<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3327<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3328 &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]3329</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3330
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3331<h5>Overview:</h5>
3332<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3333
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3334<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3335<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3336 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3337 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3338
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3339<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3340<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3341
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3342<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3343<pre>
3344 &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]3345</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3346
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3347</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3348
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3349<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3350<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3351</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3352
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3353<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3354
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3355<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3356<pre>
3357 &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]3358</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3359
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3360<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3361<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3362 division of its two arguments.</p>
3363
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3364<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3365<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3366 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3367 values. Both arguments must have identical types.</p>
3368
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3369<h5>Semantics:</h5>
3370<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3371 This instruction always performs an unsigned division to get the
3372 remainder.</p>
3373
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3374<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3375 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3376
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3377<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3378
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3379<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3380<pre>
3381 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3382</pre>
3383
3384</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3385
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3386<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3387<div class="doc_subsubsection">
3388 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3389</div>
3390
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3391<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3392
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3393<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3394<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3395 &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]3396</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3397
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3398<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3399<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3400 division of its two operands. This instruction can also take
3401 <a href="#t_vector">vector</a> versions of the values in which case the
3402 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3403
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3404<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3405<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3406 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3407 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3408
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3409<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3410<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3411 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3412 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3413 a value. For more information about the difference,
3414 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3415 Math Forum</a>. For a table of how this is implemented in various languages,
3416 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3417 Wikipedia: modulo operation</a>.</p>
3418
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3419<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3420 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3421
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3422<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3423 Overflow also leads to undefined behavior; this is a rare case, but can
3424 occur, for example, by taking the remainder of a 32-bit division of
3425 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3426 lets srem be implemented using instructions that return both the result of
3427 the division and the remainder.)</p>
3428
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3429<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3430<pre>
3431 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3432</pre>
3433
3434</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3435
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3436<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3437<div class="doc_subsubsection">
3438 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3439
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3440<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3441
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3442<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3443<pre>
3444 &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]3445</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3446
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3447<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3448<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3449 its two operands.</p>
3450
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3451<h5>Arguments:</h5>
3452<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3453 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3454 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3455
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3456<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3457<p>This instruction returns the <i>remainder</i> of a division. The remainder
3458 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3459
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3460<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3461<pre>
3462 &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]3463</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3464
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3465</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3466
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3467<!-- ======================================================================= -->
3468<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3469Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3470
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3471<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3472
3473<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3474 program. They are generally very efficient instructions and can commonly be
3475 strength reduced from other instructions. They require two operands of the
3476 same type, execute an operation on them, and produce a single value. The
3477 resulting value is the same type as its operands.</p>
3478
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3479</div>
3480
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3481<!-- _______________________________________________________________________ -->
3482<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3483Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3484
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3485<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3486
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3487<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3488<pre>
3489 &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]3490</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3491
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3492<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3493<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3494 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3495
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3496<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3497<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3498 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3499 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3500
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3501<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3502<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3503 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3504 is (statically or dynamically) negative or equal to or larger than the number
3505 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3506 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3507 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3508
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3509<h5>Example:</h5>
3510<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3511 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3512 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3513 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3514 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3515 &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]3516</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3517
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3518</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3519
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3520<!-- _______________________________________________________________________ -->
3521<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3522Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3523
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3524<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3525
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3526<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3527<pre>
3528 &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]3529</pre>
3530
3531<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3532<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3533 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3534
3535<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3536<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3537 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3538 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3539
3540<h5>Semantics:</h5>
3541<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3542 significant bits of the result will be filled with zero bits after the shift.
3543 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3544 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3545 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3546 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3547
3548<h5>Example:</h5>
3549<pre>
3550 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3551 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3552 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3553 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3554 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3555 &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]3556</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3557
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3558</div>
3559
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3560<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3561<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3562Instruction</a> </div>
3563<div class="doc_text">
3564
3565<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3566<pre>
3567 &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]3568</pre>
3569
3570<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3571<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3572 operand shifted to the right a specified number of bits with sign
3573 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3574
3575<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3576<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3577 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3578 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3579
3580<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3581<p>This instruction always performs an arithmetic shift right operation, The
3582 most significant bits of the result will be filled with the sign bit
3583 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3584 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3585 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3586 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3587
3588<h5>Example:</h5>
3589<pre>
3590 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3591 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3592 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3593 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3594 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3595 &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]3596</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3597
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3598</div>
3599
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3600<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3601<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3602Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3603
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3604<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3605
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3606<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3607<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3608 &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]3609</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3610
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3611<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3612<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3613 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3614
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3615<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3616<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3617 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3618 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3619
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3620<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3621<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3622
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3623<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3624 <tbody>
3625 <tr>
3626 <td>In0</td>
3627 <td>In1</td>
3628 <td>Out</td>
3629 </tr>
3630 <tr>
3631 <td>0</td>
3632 <td>0</td>
3633 <td>0</td>
3634 </tr>
3635 <tr>
3636 <td>0</td>
3637 <td>1</td>
3638 <td>0</td>
3639 </tr>
3640 <tr>
3641 <td>1</td>
3642 <td>0</td>
3643 <td>0</td>
3644 </tr>
3645 <tr>
3646 <td>1</td>
3647 <td>1</td>
3648 <td>1</td>
3649 </tr>
3650 </tbody>
3651</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3652
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3653<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3654<pre>
3655 &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]3656 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3657 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3658</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3659</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3660<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3661<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3662
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3663<div class="doc_text">
3664
3665<h5>Syntax:</h5>
3666<pre>
3667 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3668</pre>
3669
3670<h5>Overview:</h5>
3671<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3672 two operands.</p>
3673
3674<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3675<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3676 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3677 values. Both arguments must have identical types.</p>
3678
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3679<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3680<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3681
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3682<table border="1" cellspacing="0" cellpadding="4">
3683 <tbody>
3684 <tr>
3685 <td>In0</td>
3686 <td>In1</td>
3687 <td>Out</td>
3688 </tr>
3689 <tr>
3690 <td>0</td>
3691 <td>0</td>
3692 <td>0</td>
3693 </tr>
3694 <tr>
3695 <td>0</td>
3696 <td>1</td>
3697 <td>1</td>
3698 </tr>
3699 <tr>
3700 <td>1</td>
3701 <td>0</td>
3702 <td>1</td>
3703 </tr>
3704 <tr>
3705 <td>1</td>
3706 <td>1</td>
3707 <td>1</td>
3708 </tr>
3709 </tbody>
3710</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3711
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3712<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3713<pre>
3714 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3715 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3716 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3717</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3718
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3719</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3720
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3721<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3722<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3723Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3724
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3725<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3726
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3727<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3728<pre>
3729 &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]3730</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3731
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3732<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3733<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3734 its two operands. The <tt>xor</tt> is used to implement the "one's
3735 complement" operation, which is the "~" operator in C.</p>
3736
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3737<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3738<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3739 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3740 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3741
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3742<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3743<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3744
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3745<table border="1" cellspacing="0" cellpadding="4">
3746 <tbody>
3747 <tr>
3748 <td>In0</td>
3749 <td>In1</td>
3750 <td>Out</td>
3751 </tr>
3752 <tr>
3753 <td>0</td>
3754 <td>0</td>
3755 <td>0</td>
3756 </tr>
3757 <tr>
3758 <td>0</td>
3759 <td>1</td>
3760 <td>1</td>
3761 </tr>
3762 <tr>
3763 <td>1</td>
3764 <td>0</td>
3765 <td>1</td>
3766 </tr>
3767 <tr>
3768 <td>1</td>
3769 <td>1</td>
3770 <td>0</td>
3771 </tr>
3772 </tbody>
3773</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3774
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3775<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3776<pre>
3777 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3778 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3779 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3780 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3781</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3782
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3783</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3784
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3785<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3786<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3787 <a name="vectorops">Vector Operations</a>
3788</div>
3789
3790<div class="doc_text">
3791
3792<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3793 target-independent manner. These instructions cover the element-access and
3794 vector-specific operations needed to process vectors effectively. While LLVM
3795 does directly support these vector operations, many sophisticated algorithms
3796 will want to use target-specific intrinsics to take full advantage of a
3797 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3798
3799</div>
3800
3801<!-- _______________________________________________________________________ -->
3802<div class="doc_subsubsection">
3803 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3804</div>
3805
3806<div class="doc_text">
3807
3808<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3809<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3810 &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]3811</pre>
3812
3813<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3814<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3815 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3816
3817
3818<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3819<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3820 of <a href="#t_vector">vector</a> type. The second operand is an index
3821 indicating the position from which to extract the element. The index may be
3822 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3823
3824<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3825<p>The result is a scalar of the same type as the element type of
3826 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3827 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3828 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3829
3830<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3831<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3832 &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]3833</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3834
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3835</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3836
3837<!-- _______________________________________________________________________ -->
3838<div class="doc_subsubsection">
3839 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3840</div>
3841
3842<div class="doc_text">
3843
3844<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3845<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]3846 &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]3847</pre>
3848
3849<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3850<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3851 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3852
3853<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3854<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3855 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3856 whose type must equal the element type of the first operand. The third
3857 operand is an index indicating the position at which to insert the value.
3858 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3859
3860<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3861<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3862 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3863 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3864 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3865
3866<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3867<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3868 &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]3869</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3870
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3871</div>
3872
3873<!-- _______________________________________________________________________ -->
3874<div class="doc_subsubsection">
3875 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3876</div>
3877
3878<div class="doc_text">
3879
3880<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3881<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]3882 &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]3883</pre>
3884
3885<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3886<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3887 from two input vectors, returning a vector with the same element type as the
3888 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3889
3890<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3891<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3892 with types that match each other. The third argument is a shuffle mask whose
3893 element type is always 'i32'. The result of the instruction is a vector
3894 whose length is the same as the shuffle mask and whose element type is the
3895 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3896
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3897<p>The shuffle mask operand is required to be a constant vector with either
3898 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3899
3900<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3901<p>The elements of the two input vectors are numbered from left to right across
3902 both of the vectors. The shuffle mask operand specifies, for each element of
3903 the result vector, which element of the two input vectors the result element
3904 gets. The element selector may be undef (meaning "don't care") and the
3905 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3906
3907<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3908<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3909 &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]3910 &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]3911 &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]3912 &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]3913 &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]3914 &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]3915 &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]3916 &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]3917</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3918
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3919</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]3920
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3921<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3922<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3923 <a name="aggregateops">Aggregate Operations</a>
3924</div>
3925
3926<div class="doc_text">
3927
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3928<p>LLVM supports several instructions for working with
3929 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3930
3931</div>
3932
3933<!-- _______________________________________________________________________ -->
3934<div class="doc_subsubsection">
3935 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3936</div>
3937
3938<div class="doc_text">
3939
3940<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3941<pre>
3942 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3943</pre>
3944
3945<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3946<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
3947 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3948
3949<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3950<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3951 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
3952 <a href="#t_array">array</a> type. The operands are constant indices to
3953 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3954 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3955
3956<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3957<p>The result is the value at the position in the aggregate specified by the
3958 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3959
3960<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3961<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3962 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3963</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3964
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3965</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3966
3967<!-- _______________________________________________________________________ -->
3968<div class="doc_subsubsection">
3969 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3970</div>
3971
3972<div class="doc_text">
3973
3974<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3975<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]3976 &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]3977</pre>
3978
3979<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3980<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
3981 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3982
3983<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3984<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3985 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
3986 <a href="#t_array">array</a> type. The second operand is a first-class
3987 value to insert. The following operands are constant indices indicating
3988 the position at which to insert the value in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3989 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3990 value to insert must have the same type as the value identified by the
3991 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3992
3993<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3994<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3995 that of <tt>val</tt> except that the value at the position specified by the
3996 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3997
3998<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3999<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4000 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4001 %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]4002</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4003
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4004</div>
4005
4006
4007<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4008<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4009 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4010</div>
4011
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4012<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4013
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4014<p>A key design point of an SSA-based representation is how it represents
4015 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4016 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4017 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4018
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4019</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4020
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4021<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4022<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4023 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4024</div>
4025
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4026<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4027
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4028<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4029<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4030 &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]4031</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4032
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4033<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4034<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4035 currently executing function, to be automatically released when this function
4036 returns to its caller. The object is always allocated in the generic address
4037 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4038
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4039<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4040<p>The '<tt>alloca</tt>' instruction
4041 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4042 runtime stack, returning a pointer of the appropriate type to the program.
4043 If "NumElements" is specified, it is the number of elements allocated,
4044 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4045 specified, the value result of the allocation is guaranteed to be aligned to
4046 at least that boundary. If not specified, or if zero, the target can choose
4047 to align the allocation on any convenient boundary compatible with the
4048 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4049
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4050<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4051
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4052<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4053<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4054 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4055 memory is automatically released when the function returns. The
4056 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4057 variables that must have an address available. When the function returns
4058 (either with the <tt><a href="#i_ret">ret</a></tt>
4059 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4060 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4061
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4062<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4063<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4064 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4065 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4066 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4067 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4068</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4069
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4070</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4071
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4072<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4073<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4074Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4075
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4076<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4077
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4078<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4079<pre>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4080 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>]
4081 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>]
4082 !<index> = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4083</pre>
4084
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4085<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4086<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4087
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4088<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4089<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4090 from which to load. The pointer must point to
4091 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4092 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
4093 number or order of execution of this <tt>load</tt> with other
4094 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4095 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4096
4097<p>The optional constant "align" argument specifies the alignment of the
4098 operation (that is, the alignment of the memory address). A value of 0 or an
4099 omitted "align" argument means that the operation has the preferential
4100 alignment for the target. It is the responsibility of the code emitter to
4101 ensure that the alignment information is correct. Overestimating the
4102 alignment results in an undefined behavior. Underestimating the alignment may
4103 produce less efficient code. An alignment of 1 is always safe.</p>
4104
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4105<p>The optional !nontemporal metadata must reference a single metatadata
4106 name <index> corresponding to a metadata node with one i32 entry of
4107 value 1. The existance of the !nontemporal metatadata on the
4108 instruction tells the optimizer and code generator that this load is
4109 not expected to be reused in the cache. The code generator may
4110 select special instructions to save cache bandwidth, such as the
4111 MOVNT intruction on x86.</p>
4112
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4113<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4114<p>The location of memory pointed to is loaded. If the value being loaded is of
4115 scalar type then the number of bytes read does not exceed the minimum number
4116 of bytes needed to hold all bits of the type. For example, loading an
4117 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4118 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4119 is undefined if the value was not originally written using a store of the
4120 same type.</p>
4121
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4122<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4123<pre>
4124 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4125 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4126 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4127</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4128
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4129</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4130
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4131<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4132<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4133Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4134
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4135<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4136
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4137<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4138<pre>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4139 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4140 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4141</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4142
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4143<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4144<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4145
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4146<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4147<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4148 and an address at which to store it. The type of the
4149 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4150 the <a href="#t_firstclass">first class</a> type of the
4151 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4152 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4153 or order of execution of this <tt>store</tt> with other
4154 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4155 instructions.</p>
4156
4157<p>The optional constant "align" argument specifies the alignment of the
4158 operation (that is, the alignment of the memory address). A value of 0 or an
4159 omitted "align" argument means that the operation has the preferential
4160 alignment for the target. It is the responsibility of the code emitter to
4161 ensure that the alignment information is correct. Overestimating the
4162 alignment results in an undefined behavior. Underestimating the alignment may
4163 produce less efficient code. An alignment of 1 is always safe.</p>
4164
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4165<p>The optional !nontemporal metadata must reference a single metatadata
4166 name <index> corresponding to a metadata node with one i32 entry of
4167 value 1. The existance of the !nontemporal metatadata on the
4168 instruction tells the optimizer and code generator that this load is
4169 not expected to be reused in the cache. The code generator may
4170 select special instructions to save cache bandwidth, such as the
4171 MOVNT intruction on x86.</p>
4172
4173
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4174<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4175<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4176 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4177 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4178 does not exceed the minimum number of bytes needed to hold all bits of the
4179 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4180 writing a value of a type like <tt>i20</tt> with a size that is not an
4181 integral number of bytes, it is unspecified what happens to the extra bits
4182 that do not belong to the type, but they will typically be overwritten.</p>
4183
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4184<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4185<pre>
4186 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4187 store i32 3, i32* %ptr <i>; yields {void}</i>
4188 %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]4189</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4190
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4191</div>
4192
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4193<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4194<div class="doc_subsubsection">
4195 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4196</div>
4197
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4198<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4199
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4200<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4201<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4202 &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]4203 &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]4204</pre>
4205
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4206<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4207<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4208 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4209 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4210
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4211<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4212<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4213 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4214 elements of the aggregate object are indexed. The interpretation of each
4215 index is dependent on the type being indexed into. The first index always
4216 indexes the pointer value given as the first argument, the second index
4217 indexes a value of the type pointed to (not necessarily the value directly
4218 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4219 indexed into must be a pointer value, subsequent types can be arrays,
4220 vectors, structs and unions. Note that subsequent types being indexed into
4221 can never be pointers, since that would require loading the pointer before
4222 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4223
4224<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4225 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4226 integer <b>constants</b> are allowed. When indexing into an array, pointer
4227 or vector, integers of any width are allowed, and they are not required to be
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4228 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4229
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4230<p>For example, let's consider a C code fragment and how it gets compiled to
4231 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4232
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4233<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4234<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4235struct RT {
4236 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4237 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4238 char C;
4239};
4240struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4241 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4242 double Y;
4243 struct RT Z;
4244};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4245
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4246int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4247 return &amp;s[1].Z.B[5][13];
4248}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4249</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4250</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4251
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4252<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4253
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4254<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4255<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4256%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4257%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4258
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4259define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4260entry:
4261 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4262 ret i32* %reg
4263}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4264</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4265</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4266
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4267<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4268<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]4269 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4270 }</tt>' type, a structure. The second index indexes into the third element
4271 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4272 i8 }</tt>' type, another structure. The third index indexes into the second
4273 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4274 array. The two dimensions of the array are subscripted into, yielding an
4275 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4276 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4277
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4278<p>Note that it is perfectly legal to index partially through a structure,
4279 returning a pointer to an inner element. Because of this, the LLVM code for
4280 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4281
4282<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4283 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4284 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4285 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4286 %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]4287 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4288 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4289 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4290 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4291</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4292
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4293<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4294 <tt>getelementptr</tt> is undefined if the base pointer is not an
4295 <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]4296 that would be formed by successive addition of the offsets implied by the
4297 indices to the base address with infinitely precise arithmetic are not an
4298 <i>in bounds</i> address of that allocated object.
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4299 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohman2de532c2009-08-20 17:08:17 +0000[diff] [blame]4300 that point into the object, plus the address one byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4301
4302<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4303 the base address with silently-wrapping two's complement arithmetic, and
4304 the result value of the <tt>getelementptr</tt> may be outside the object
4305 pointed to by the base pointer. The result value may not necessarily be
4306 used to access memory though, even if it happens to point into allocated
4307 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4308 section for more information.</p>
4309
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4310<p>The getelementptr instruction is often confusing. For some more insight into
4311 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4312
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4313<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4314<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4315 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4316 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4317 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4318 %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]4319 <i>; yields i8*:eptr</i>
4320 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4321 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4322 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4323</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4324
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4325</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4326
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4327<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4328<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4329</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4330
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4331<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4332
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4333<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4334 which all take a single operand and a type. They perform various bit
4335 conversions on the operand.</p>
4336
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4337</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4338
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4339<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4340<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4341 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4342</div>
4343<div class="doc_text">
4344
4345<h5>Syntax:</h5>
4346<pre>
4347 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4348</pre>
4349
4350<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4351<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4352 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4353
4354<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4355<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4356 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4357 size and type of the result, which must be
4358 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4359 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4360 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4361
4362<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4363<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4364 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4365 source size must be larger than the destination size, <tt>trunc</tt> cannot
4366 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4367
4368<h5>Example:</h5>
4369<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4370 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4371 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4372 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4373</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4374
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4375</div>
4376
4377<!-- _______________________________________________________________________ -->
4378<div class="doc_subsubsection">
4379 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4380</div>
4381<div class="doc_text">
4382
4383<h5>Syntax:</h5>
4384<pre>
4385 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4386</pre>
4387
4388<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4389<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4390 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4391
4392
4393<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4394<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]4395 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4396 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]4397 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4398 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4399
4400<h5>Semantics:</h5>
4401<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]4402 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4403
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4404<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]4405
4406<h5>Example:</h5>
4407<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4408 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4409 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4410</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4411
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4412</div>
4413
4414<!-- _______________________________________________________________________ -->
4415<div class="doc_subsubsection">
4416 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4417</div>
4418<div class="doc_text">
4419
4420<h5>Syntax:</h5>
4421<pre>
4422 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4423</pre>
4424
4425<h5>Overview:</h5>
4426<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4427
4428<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4429<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]4430 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4431 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]4432 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4433 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4434
4435<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4436<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4437 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4438 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4439
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4440<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]4441
4442<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4443<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4444 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4445 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4446</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4447
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4448</div>
4449
4450<!-- _______________________________________________________________________ -->
4451<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4452 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4453</div>
4454
4455<div class="doc_text">
4456
4457<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4458<pre>
4459 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4460</pre>
4461
4462<h5>Overview:</h5>
4463<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4464 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4465
4466<h5>Arguments:</h5>
4467<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4468 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4469 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]4470 <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]4471 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4472
4473<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4474<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4475 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4476 <a href="#t_floating">floating point</a> type. If the value cannot fit
4477 within the destination type, <tt>ty2</tt>, then the results are
4478 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4479
4480<h5>Example:</h5>
4481<pre>
4482 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4483 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4484</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4485
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4486</div>
4487
4488<!-- _______________________________________________________________________ -->
4489<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4490 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4491</div>
4492<div class="doc_text">
4493
4494<h5>Syntax:</h5>
4495<pre>
4496 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4497</pre>
4498
4499<h5>Overview:</h5>
4500<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]4501 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4502
4503<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4504<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4505 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4506 a <a href="#t_floating">floating point</a> type to cast it to. The source
4507 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4508
4509<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4510<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4511 <a href="#t_floating">floating point</a> type to a larger
4512 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4513 used to make a <i>no-op cast</i> because it always changes bits. Use
4514 <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]4515
4516<h5>Example:</h5>
4517<pre>
4518 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4519 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4520</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4521
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4522</div>
4523
4524<!-- _______________________________________________________________________ -->
4525<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4526 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4527</div>
4528<div class="doc_text">
4529
4530<h5>Syntax:</h5>
4531<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4532 &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]4533</pre>
4534
4535<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4536<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4537 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4538
4539<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4540<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4541 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4542 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4543 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4544 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4545
4546<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4547<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4548 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4549 towards zero) unsigned integer value. If the value cannot fit
4550 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4551
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4552<h5>Example:</h5>
4553<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4554 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4555 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4556 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4557</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4558
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4559</div>
4560
4561<!-- _______________________________________________________________________ -->
4562<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4563 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4564</div>
4565<div class="doc_text">
4566
4567<h5>Syntax:</h5>
4568<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4569 &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]4570</pre>
4571
4572<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4573<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4574 <a href="#t_floating">floating point</a> <tt>value</tt> to
4575 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4576
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4577<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4578<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4579 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4580 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4581 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4582 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4583
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4584<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4585<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4586 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4587 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4588 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4589
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4590<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4591<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4592 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4593 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4594 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4595</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4596
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4597</div>
4598
4599<!-- _______________________________________________________________________ -->
4600<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4601 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4602</div>
4603<div class="doc_text">
4604
4605<h5>Syntax:</h5>
4606<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4607 &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]4608</pre>
4609
4610<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4611<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4612 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4613
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4614<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4615<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]4616 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4617 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4618 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4619 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4620
4621<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4622<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4623 integer quantity and converts it to the corresponding floating point
4624 value. If the value cannot fit in the floating point value, the results are
4625 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4626
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4627<h5>Example:</h5>
4628<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4629 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4630 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4631</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4632
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4633</div>
4634
4635<!-- _______________________________________________________________________ -->
4636<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4637 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4638</div>
4639<div class="doc_text">
4640
4641<h5>Syntax:</h5>
4642<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4643 &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]4644</pre>
4645
4646<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4647<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4648 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4649
4650<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4651<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]4652 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4653 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4654 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4655 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4656
4657<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4658<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4659 quantity and converts it to the corresponding floating point value. If the
4660 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4661
4662<h5>Example:</h5>
4663<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4664 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4665 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4666</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4667
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4668</div>
4669
4670<!-- _______________________________________________________________________ -->
4671<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4672 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4673</div>
4674<div class="doc_text">
4675
4676<h5>Syntax:</h5>
4677<pre>
4678 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4679</pre>
4680
4681<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4682<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4683 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4684
4685<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4686<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4687 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4688 <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]4689
4690<h5>Semantics:</h5>
4691<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4692 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4693 truncating or zero extending that value to the size of the integer type. If
4694 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4695 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4696 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4697 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4698
4699<h5>Example:</h5>
4700<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4701 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4702 %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]4703</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4704
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4705</div>
4706
4707<!-- _______________________________________________________________________ -->
4708<div class="doc_subsubsection">
4709 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4710</div>
4711<div class="doc_text">
4712
4713<h5>Syntax:</h5>
4714<pre>
4715 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4716</pre>
4717
4718<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4719<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4720 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4721
4722<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4723<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4724 value to cast, and a type to cast it to, which must be a
4725 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4726
4727<h5>Semantics:</h5>
4728<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4729 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4730 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4731 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4732 than the size of a pointer then a zero extension is done. If they are the
4733 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4734
4735<h5>Example:</h5>
4736<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4737 %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]4738 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4739 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4740</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4741
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4742</div>
4743
4744<!-- _______________________________________________________________________ -->
4745<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4746 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4747</div>
4748<div class="doc_text">
4749
4750<h5>Syntax:</h5>
4751<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4752 &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]4753</pre>
4754
4755<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4756<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4757 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4758
4759<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4760<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4761 non-aggregate first class value, and a type to cast it to, which must also be
4762 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4763 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4764 identical. If the source type is a pointer, the destination type must also be
4765 a pointer. This instruction supports bitwise conversion of vectors to
4766 integers and to vectors of other types (as long as they have the same
4767 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4768
4769<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4770<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4771 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4772 this conversion. The conversion is done as if the <tt>value</tt> had been
4773 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4774 be converted to other pointer types with this instruction. To convert
4775 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4776 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4777
4778<h5>Example:</h5>
4779<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4780 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4781 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4782 %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]4783</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4784
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4785</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4786
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4787<!-- ======================================================================= -->
4788<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4789
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4790<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4791
4792<p>The instructions in this category are the "miscellaneous" instructions, which
4793 defy better classification.</p>
4794
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4795</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4796
4797<!-- _______________________________________________________________________ -->
4798<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4799</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4800
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4801<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4802
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4803<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4804<pre>
4805 &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]4806</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4807
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4808<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4809<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4810 boolean values based on comparison of its two integer, integer vector, or
4811 pointer operands.</p>
4812
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4813<h5>Arguments:</h5>
4814<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4815 the condition code indicating the kind of comparison to perform. It is not a
4816 value, just a keyword. The possible condition code are:</p>
4817
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4818<ol>
4819 <li><tt>eq</tt>: equal</li>
4820 <li><tt>ne</tt>: not equal </li>
4821 <li><tt>ugt</tt>: unsigned greater than</li>
4822 <li><tt>uge</tt>: unsigned greater or equal</li>
4823 <li><tt>ult</tt>: unsigned less than</li>
4824 <li><tt>ule</tt>: unsigned less or equal</li>
4825 <li><tt>sgt</tt>: signed greater than</li>
4826 <li><tt>sge</tt>: signed greater or equal</li>
4827 <li><tt>slt</tt>: signed less than</li>
4828 <li><tt>sle</tt>: signed less or equal</li>
4829</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4830
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]4831<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4832 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4833 typed. They must also be identical types.</p>
4834
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4835<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4836<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4837 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4838 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]4839 result, as follows:</p>
4840
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4841<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4842 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4843 <tt>false</tt> otherwise. No sign interpretation is necessary or
4844 performed.</li>
4845
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4846 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4847 <tt>false</tt> otherwise. No sign interpretation is necessary or
4848 performed.</li>
4849
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4850 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4851 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4852
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4853 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4854 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4855 to <tt>op2</tt>.</li>
4856
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4857 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4858 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4859
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4860 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4861 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4862
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4863 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4864 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4865
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4866 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4867 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4868 to <tt>op2</tt>.</li>
4869
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4870 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4871 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4872
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4873 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4874 <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]4875</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4876
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4877<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4878 values are compared as if they were integers.</p>
4879
4880<p>If the operands are integer vectors, then they are compared element by
4881 element. The result is an <tt>i1</tt> vector with the same number of elements
4882 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4883
4884<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4885<pre>
4886 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4887 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4888 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4889 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4890 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4891 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4892</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4893
4894<p>Note that the code generator does not yet support vector types with
4895 the <tt>icmp</tt> instruction.</p>
4896
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4897</div>
4898
4899<!-- _______________________________________________________________________ -->
4900<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4901</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4902
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4903<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4904
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4905<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4906<pre>
4907 &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]4908</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4909
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4910<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4911<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4912 values based on comparison of its operands.</p>
4913
4914<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]4915(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4916
4917<p>If the operands are floating point vectors, then the result type is a vector
4918 of boolean with the same number of elements as the operands being
4919 compared.</p>
4920
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4921<h5>Arguments:</h5>
4922<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4923 the condition code indicating the kind of comparison to perform. It is not a
4924 value, just a keyword. The possible condition code are:</p>
4925
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4926<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4927 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4928 <li><tt>oeq</tt>: ordered and equal</li>
4929 <li><tt>ogt</tt>: ordered and greater than </li>
4930 <li><tt>oge</tt>: ordered and greater than or equal</li>
4931 <li><tt>olt</tt>: ordered and less than </li>
4932 <li><tt>ole</tt>: ordered and less than or equal</li>
4933 <li><tt>one</tt>: ordered and not equal</li>
4934 <li><tt>ord</tt>: ordered (no nans)</li>
4935 <li><tt>ueq</tt>: unordered or equal</li>
4936 <li><tt>ugt</tt>: unordered or greater than </li>
4937 <li><tt>uge</tt>: unordered or greater than or equal</li>
4938 <li><tt>ult</tt>: unordered or less than </li>
4939 <li><tt>ule</tt>: unordered or less than or equal</li>
4940 <li><tt>une</tt>: unordered or not equal</li>
4941 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4942 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4943</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4944
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4945<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4946 <i>unordered</i> means that either operand may be a QNAN.</p>
4947
4948<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4949 a <a href="#t_floating">floating point</a> type or
4950 a <a href="#t_vector">vector</a> of floating point type. They must have
4951 identical types.</p>
4952
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4953<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4954<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4955 according to the condition code given as <tt>cond</tt>. If the operands are
4956 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4957 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4958 follows:</p>
4959
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4960<ol>
4961 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4962
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4963 <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]4964 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4965
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4966 <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]4967 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4968
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4969 <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]4970 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4971
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4972 <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]4973 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4974
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4975 <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]4976 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4977
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4978 <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]4979 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4980
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4981 <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]4982
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4983 <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]4984 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4985
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4986 <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]4987 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4988
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4989 <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]4990 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4991
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4992 <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]4993 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4994
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4995 <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]4996 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4997
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4998 <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]4999 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5000
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5001 <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]5002
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5003 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5004</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5005
5006<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5007<pre>
5008 &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]5009 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5010 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5011 &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]5012</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5013
5014<p>Note that the code generator does not yet support vector types with
5015 the <tt>fcmp</tt> instruction.</p>
5016
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5017</div>
5018
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5019<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5020<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5021 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5022</div>
5023
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5024<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5025
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5026<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5027<pre>
5028 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5029</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5030
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5031<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5032<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5033 SSA graph representing the function.</p>
5034
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5035<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5036<p>The type of the incoming values is specified with the first type field. After
5037 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5038 one pair for each predecessor basic block of the current block. Only values
5039 of <a href="#t_firstclass">first class</a> type may be used as the value
5040 arguments to the PHI node. Only labels may be used as the label
5041 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5042
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5043<p>There must be no non-phi instructions between the start of a basic block and
5044 the PHI instructions: i.e. PHI instructions must be first in a basic
5045 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5046
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5047<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5048 occur on the edge from the corresponding predecessor block to the current
5049 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5050 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5051
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5052<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5053<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5054 specified by the pair corresponding to the predecessor basic block that
5055 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5056
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5057<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5058<pre>
5059Loop: ; Infinite loop that counts from 0 on up...
5060 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5061 %nextindvar = add i32 %indvar, 1
5062 br label %Loop
5063</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5064
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5065</div>
5066
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5067<!-- _______________________________________________________________________ -->
5068<div class="doc_subsubsection">
5069 <a name="i_select">'<tt>select</tt>' Instruction</a>
5070</div>
5071
5072<div class="doc_text">
5073
5074<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5075<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5076 &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>
5077
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5078 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5079</pre>
5080
5081<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5082<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5083 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5084
5085
5086<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5087<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5088 values indicating the condition, and two values of the
5089 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5090 vectors and the condition is a scalar, then entire vectors are selected, not
5091 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5092
5093<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5094<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5095 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5096
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5097<p>If the condition is a vector of i1, then the value arguments must be vectors
5098 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5099
5100<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5101<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5102 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5103</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5104
5105<p>Note that the code generator does not yet support conditions
5106 with vector type.</p>
5107
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5108</div>
5109
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5110<!-- _______________________________________________________________________ -->
5111<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5112 <a name="i_call">'<tt>call</tt>' Instruction</a>
5113</div>
5114
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5115<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5116
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5117<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5118<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5119 &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]5120</pre>
5121
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5122<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5123<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5124
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5125<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5126<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5127
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5128<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5129 <li>The optional "tail" marker indicates that the callee function does not
5130 access any allocas or varargs in the caller. Note that calls may be
5131 marked "tail" even if they do not occur before
5132 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5133 present, the function call is eligible for tail call optimization,
5134 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
5135 optimized into a jump</a>. As of this writing, the extra requirements for
5136 a call to actually be optimized are:
5137 <ul>
5138 <li>Caller and callee both have the calling
5139 convention <tt>fastcc</tt>.</li>
5140 <li>The call is in tail position (ret immediately follows call and ret
5141 uses value of call or is void).</li>
5142 <li>Option <tt>-tailcallopt</tt> is enabled,
5143 or <code>llvm::PerformTailCallOpt</code> is <code>true</code>.</li>
5144 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5145 constraints are met.</a></li>
5146 </ul>
5147 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5148
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5149 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5150 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5151 defaults to using C calling conventions. The calling convention of the
5152 call must match the calling convention of the target function, or else the
5153 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5154
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5155 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5156 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5157 '<tt>inreg</tt>' attributes are valid here.</li>
5158
5159 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5160 type of the return value. Functions that return no value are marked
5161 <tt><a href="#t_void">void</a></tt>.</li>
5162
5163 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5164 being invoked. The argument types must match the types implied by this
5165 signature. This type can be omitted if the function is not varargs and if
5166 the function type does not return a pointer to a function.</li>
5167
5168 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5169 be invoked. In most cases, this is a direct function invocation, but
5170 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5171 to function value.</li>
5172
5173 <li>'<tt>function args</tt>': argument list whose types match the function
5174 signature argument types. All arguments must be of
5175 <a href="#t_firstclass">first class</a> type. If the function signature
5176 indicates the function accepts a variable number of arguments, the extra
5177 arguments can be specified.</li>
5178
5179 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5180 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5181 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5182</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5183
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5184<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5185<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5186 a specified function, with its incoming arguments bound to the specified
5187 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5188 function, control flow continues with the instruction after the function
5189 call, and the return value of the function is bound to the result
5190 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5191
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5192<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5193<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5194 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5195 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5196 %X = tail call i32 @foo() <i>; yields i32</i>
5197 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5198 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5199
5200 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5201 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5202 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5203 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5204 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5205 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5206</pre>
5207
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5208<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5209standard C99 library as being the C99 library functions, and may perform
5210optimizations or generate code for them under that assumption. This is
5211something we'd like to change in the future to provide better support for
5212freestanding environments and non-C-based langauges.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5213
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5214</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5215
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5216<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5217<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5218 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5219</div>
5220
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5221<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5222
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5223<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5224<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5225 &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]5226</pre>
5227
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5228<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5229<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5230 the "variable argument" area of a function call. It is used to implement the
5231 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5232
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5233<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5234<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5235 argument. It returns a value of the specified argument type and increments
5236 the <tt>va_list</tt> to point to the next argument. The actual type
5237 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5238
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5239<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5240<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5241 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5242 to the next argument. For more information, see the variable argument
5243 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5244
5245<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]5246 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5247 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5248
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5249<p><tt>va_arg</tt> is an LLVM instruction instead of
5250 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5251 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5252
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5253<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5254<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5255
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5256<p>Note that the code generator does not yet fully support va_arg on many
5257 targets. Also, it does not currently support va_arg with aggregate types on
5258 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5259
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5260</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5261
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5262<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5263<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5264<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5265
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5266<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5267
5268<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5269 well known names and semantics and are required to follow certain
5270 restrictions. Overall, these intrinsics represent an extension mechanism for
5271 the LLVM language that does not require changing all of the transformations
5272 in LLVM when adding to the language (or the bitcode reader/writer, the
5273 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5274
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5275<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5276 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5277 begin with this prefix. Intrinsic functions must always be external
5278 functions: you cannot define the body of intrinsic functions. Intrinsic
5279 functions may only be used in call or invoke instructions: it is illegal to
5280 take the address of an intrinsic function. Additionally, because intrinsic
5281 functions are part of the LLVM language, it is required if any are added that
5282 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5283
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5284<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5285 family of functions that perform the same operation but on different data
5286 types. Because LLVM can represent over 8 million different integer types,
5287 overloading is used commonly to allow an intrinsic function to operate on any
5288 integer type. One or more of the argument types or the result type can be
5289 overloaded to accept any integer type. Argument types may also be defined as
5290 exactly matching a previous argument's type or the result type. This allows
5291 an intrinsic function which accepts multiple arguments, but needs all of them
5292 to be of the same type, to only be overloaded with respect to a single
5293 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5294
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5295<p>Overloaded intrinsics will have the names of its overloaded argument types
5296 encoded into its function name, each preceded by a period. Only those types
5297 which are overloaded result in a name suffix. Arguments whose type is matched
5298 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5299 can take an integer of any width and returns an integer of exactly the same
5300 integer width. This leads to a family of functions such as
5301 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5302 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5303 suffix is required. Because the argument's type is matched against the return
5304 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5305
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5306<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5307 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5308
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5309</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5310
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5311<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5312<div class="doc_subsection">
5313 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5314</div>
5315
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5316<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5317
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5318<p>Variable argument support is defined in LLVM with
5319 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5320 intrinsic functions. These functions are related to the similarly named
5321 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5322
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5323<p>All of these functions operate on arguments that use a target-specific value
5324 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5325 not define what this type is, so all transformations should be prepared to
5326 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5327
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5328<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]5329 instruction and the variable argument handling intrinsic functions are
5330 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5331
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5332<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5333<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5334define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5335 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5336 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5337 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5338 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5339
5340 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5341 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5342
5343 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5344 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5345 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5346 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5347 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5348
5349 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5350 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5351 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5352}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5353
5354declare void @llvm.va_start(i8*)
5355declare void @llvm.va_copy(i8*, i8*)
5356declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5357</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5358</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5359
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5360</div>
5361
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5362<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5363<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5364 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5365</div>
5366
5367
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5368<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5369
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5370<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5371<pre>
5372 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5373</pre>
5374
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5375<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5376<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5377 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]5378
5379<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5380<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]5381
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5382<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5383<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]5384 macro available in C. In a target-dependent way, it initializes
5385 the <tt>va_list</tt> element to which the argument points, so that the next
5386 call to <tt>va_arg</tt> will produce the first variable argument passed to
5387 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5388 need to know the last argument of the function as the compiler can figure
5389 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5390
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5391</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5392
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5393<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5394<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5395 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5396</div>
5397
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5398<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5399
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5400<h5>Syntax:</h5>
5401<pre>
5402 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5403</pre>
5404
5405<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5406<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5407 which has been initialized previously
5408 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5409 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5410
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5411<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5412<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]5413
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5414<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5415<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]5416 macro available in C. In a target-dependent way, it destroys
5417 the <tt>va_list</tt> element to which the argument points. Calls
5418 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5419 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5420 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5421
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5422</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5423
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5424<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5425<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5426 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5427</div>
5428
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5429<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5430
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5431<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5432<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5433 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5434</pre>
5435
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5436<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5437<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5438 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5439
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5440<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5441<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]5442 The second argument is a pointer to a <tt>va_list</tt> element to copy
5443 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5444
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5445<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5446<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]5447 macro available in C. In a target-dependent way, it copies the
5448 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5449 element. This intrinsic is necessary because
5450 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5451 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5452
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5453</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5454
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5455<!-- ======================================================================= -->
5456<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5457 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5458</div>
5459
5460<div class="doc_text">
5461
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5462<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5463Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5464intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5465roots on the stack</a>, as well as garbage collector implementations that
5466require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5467barriers. Front-ends for type-safe garbage collected languages should generate
5468these intrinsics to make use of the LLVM garbage collectors. For more details,
5469see <a href="GarbageCollection.html">Accurate Garbage Collection with
5470LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5471
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5472<p>The garbage collection intrinsics only operate on objects in the generic
5473 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5474
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5475</div>
5476
5477<!-- _______________________________________________________________________ -->
5478<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5479 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5480</div>
5481
5482<div class="doc_text">
5483
5484<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5485<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5486 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5487</pre>
5488
5489<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5490<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]5491 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5492
5493<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5494<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5495 root pointer. The second pointer (which must be either a constant or a
5496 global value address) contains the meta-data to be associated with the
5497 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5498
5499<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5500<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]5501 location. At compile-time, the code generator generates information to allow
5502 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5503 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5504 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5505
5506</div>
5507
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5508<!-- _______________________________________________________________________ -->
5509<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5510 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5511</div>
5512
5513<div class="doc_text">
5514
5515<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5516<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5517 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5518</pre>
5519
5520<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5521<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5522 locations, allowing garbage collector implementations that require read
5523 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5524
5525<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5526<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]5527 allocated from the garbage collector. The first object is a pointer to the
5528 start of the referenced object, if needed by the language runtime (otherwise
5529 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5530
5531<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5532<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5533 instruction, but may be replaced with substantially more complex code by the
5534 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5535 may only be used in a function which <a href="#gc">specifies a GC
5536 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5537
5538</div>
5539
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5540<!-- _______________________________________________________________________ -->
5541<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5542 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5543</div>
5544
5545<div class="doc_text">
5546
5547<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5548<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5549 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5550</pre>
5551
5552<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5553<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5554 locations, allowing garbage collector implementations that require write
5555 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5556
5557<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5558<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]5559 object to store it to, and the third is the address of the field of Obj to
5560 store to. If the runtime does not require a pointer to the object, Obj may
5561 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5562
5563<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5564<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5565 instruction, but may be replaced with substantially more complex code by the
5566 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5567 may only be used in a function which <a href="#gc">specifies a GC
5568 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5569
5570</div>
5571
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5572<!-- ======================================================================= -->
5573<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5574 <a name="int_codegen">Code Generator Intrinsics</a>
5575</div>
5576
5577<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5578
5579<p>These intrinsics are provided by LLVM to expose special features that may
5580 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5581
5582</div>
5583
5584<!-- _______________________________________________________________________ -->
5585<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5586 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5587</div>
5588
5589<div class="doc_text">
5590
5591<h5>Syntax:</h5>
5592<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5593 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5594</pre>
5595
5596<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5597<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5598 target-specific value indicating the return address of the current function
5599 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5600
5601<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5602<p>The argument to this intrinsic indicates which function to return the address
5603 for. Zero indicates the calling function, one indicates its caller, etc.
5604 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5605
5606<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5607<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5608 indicating the return address of the specified call frame, or zero if it
5609 cannot be identified. The value returned by this intrinsic is likely to be
5610 incorrect or 0 for arguments other than zero, so it should only be used for
5611 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5612
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5613<p>Note that calling this intrinsic does not prevent function inlining or other
5614 aggressive transformations, so the value returned may not be that of the
5615 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5616
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5617</div>
5618
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5619<!-- _______________________________________________________________________ -->
5620<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5621 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5622</div>
5623
5624<div class="doc_text">
5625
5626<h5>Syntax:</h5>
5627<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5628 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5629</pre>
5630
5631<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5632<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5633 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5634
5635<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5636<p>The argument to this intrinsic indicates which function to return the frame
5637 pointer for. Zero indicates the calling function, one indicates its caller,
5638 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5639
5640<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5641<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5642 indicating the frame address of the specified call frame, or zero if it
5643 cannot be identified. The value returned by this intrinsic is likely to be
5644 incorrect or 0 for arguments other than zero, so it should only be used for
5645 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5646
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5647<p>Note that calling this intrinsic does not prevent function inlining or other
5648 aggressive transformations, so the value returned may not be that of the
5649 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5650
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5651</div>
5652
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5653<!-- _______________________________________________________________________ -->
5654<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5655 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5656</div>
5657
5658<div class="doc_text">
5659
5660<h5>Syntax:</h5>
5661<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5662 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5663</pre>
5664
5665<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5666<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5667 of the function stack, for use
5668 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5669 useful for implementing language features like scoped automatic variable
5670 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5671
5672<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5673<p>This intrinsic returns a opaque pointer value that can be passed
5674 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5675 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5676 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5677 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5678 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5679 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +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_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5686</div>
5687
5688<div class="doc_text">
5689
5690<h5>Syntax:</h5>
5691<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5692 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5693</pre>
5694
5695<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5696<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5697 the function stack to the state it was in when the
5698 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5699 executed. This is useful for implementing language features like scoped
5700 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5701
5702<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5703<p>See the description
5704 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5705
5706</div>
5707
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5708<!-- _______________________________________________________________________ -->
5709<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5710 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5711</div>
5712
5713<div class="doc_text">
5714
5715<h5>Syntax:</h5>
5716<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5717 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]5718</pre>
5719
5720<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5721<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5722 insert a prefetch instruction if supported; otherwise, it is a noop.
5723 Prefetches have no effect on the behavior of the program but can change its
5724 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5725
5726<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5727<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5728 specifier determining if the fetch should be for a read (0) or write (1),
5729 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5730 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5731 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5732
5733<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5734<p>This intrinsic does not modify the behavior of the program. In particular,
5735 prefetches cannot trap and do not produce a value. On targets that support
5736 this intrinsic, the prefetch can provide hints to the processor cache for
5737 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5738
5739</div>
5740
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5741<!-- _______________________________________________________________________ -->
5742<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5743 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5744</div>
5745
5746<div class="doc_text">
5747
5748<h5>Syntax:</h5>
5749<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5750 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +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.pcmarker</tt>' intrinsic is a method to export a Program
5755 Counter (PC) in a region of code to simulators and other tools. The method
5756 is target specific, but it is expected that the marker will use exported
5757 symbols to transmit the PC of the marker. The marker makes no guarantees
5758 that it will remain with any specific instruction after optimizations. It is
5759 possible that the presence of a marker will inhibit optimizations. The
5760 intended use is to be inserted after optimizations to allow correlations of
5761 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5762
5763<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5764<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5765
5766<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5767<p>This intrinsic does not modify the behavior of the program. Backends that do
5768 not support this intrinisic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5769
5770</div>
5771
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5772<!-- _______________________________________________________________________ -->
5773<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5774 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5775</div>
5776
5777<div class="doc_text">
5778
5779<h5>Syntax:</h5>
5780<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5781 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5782</pre>
5783
5784<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5785<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5786 counter register (or similar low latency, high accuracy clocks) on those
5787 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5788 should map to RPCC. As the backing counters overflow quickly (on the order
5789 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5790
5791<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5792<p>When directly supported, reading the cycle counter should not modify any
5793 memory. Implementations are allowed to either return a application specific
5794 value or a system wide value. On backends without support, this is lowered
5795 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5796
5797</div>
5798
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5799<!-- ======================================================================= -->
5800<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5801 <a name="int_libc">Standard C Library Intrinsics</a>
5802</div>
5803
5804<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5805
5806<p>LLVM provides intrinsics for a few important standard C library functions.
5807 These intrinsics allow source-language front-ends to pass information about
5808 the alignment of the pointer arguments to the code generator, providing
5809 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5810
5811</div>
5812
5813<!-- _______________________________________________________________________ -->
5814<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5815 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5816</div>
5817
5818<div class="doc_text">
5819
5820<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5821<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5822 integer bit width. Not all targets support all bit widths however.</p>
5823
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5824<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5825 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5826 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5827 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5828 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5829 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5830 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5831 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5832 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5833</pre>
5834
5835<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5836<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5837 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5838
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5839<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5840 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5841
5842<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5843<p>The first argument is a pointer to the destination, the second is a pointer
5844 to the source. The third argument is an integer argument specifying the
5845 number of bytes to copy, and the fourth argument is the alignment of the
5846 source and destination locations.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5847
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5848<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5849 then the caller guarantees that both the source and destination pointers are
5850 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5851
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5852<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5853<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5854 source location to the destination location, which are not allowed to
5855 overlap. It copies "len" bytes of memory over. If the argument is known to
5856 be aligned to some boundary, this can be specified as the fourth argument,
5857 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5858
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5859</div>
5860
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5861<!-- _______________________________________________________________________ -->
5862<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5863 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5864</div>
5865
5866<div class="doc_text">
5867
5868<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5869<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]5870 width. Not all targets support all bit widths however.</p>
5871
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5872<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5873 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5874 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5875 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5876 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5877 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5878 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5879 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5880 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5881</pre>
5882
5883<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5884<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5885 source location to the destination location. It is similar to the
5886 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5887 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5888
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5889<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5890 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5891
5892<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5893<p>The first argument is a pointer to the destination, the second is a pointer
5894 to the source. The third argument is an integer argument specifying the
5895 number of bytes to copy, and the fourth argument is the alignment of the
5896 source and destination locations.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5897
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5898<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5899 then the caller guarantees that the source and destination pointers are
5900 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5901
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5902<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5903<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5904 source location to the destination location, which may overlap. It copies
5905 "len" bytes of memory over. If the argument is known to be aligned to some
5906 boundary, this can be specified as the fourth argument, otherwise it should
5907 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5908
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5909</div>
5910
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5911<!-- _______________________________________________________________________ -->
5912<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5913 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5914</div>
5915
5916<div class="doc_text">
5917
5918<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5919<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]5920 width. Not all targets support all bit widths however.</p>
5921
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5922<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5923 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5924 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5925 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5926 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5927 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5928 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5929 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5930 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5931</pre>
5932
5933<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5934<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5935 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5936
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5937<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5938 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5939
5940<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5941<p>The first argument is a pointer to the destination to fill, the second is the
5942 byte value to fill it with, the third argument is an integer argument
5943 specifying the number of bytes to fill, and the fourth argument is the known
5944 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5945
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5946<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5947 then the caller guarantees that the destination pointer is aligned to that
5948 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5949
5950<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5951<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5952 at the destination location. If the argument is known to be aligned to some
5953 boundary, this can be specified as the fourth argument, otherwise it should
5954 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5955
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5956</div>
5957
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5958<!-- _______________________________________________________________________ -->
5959<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5960 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5961</div>
5962
5963<div class="doc_text">
5964
5965<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5966<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5967 floating point or vector of floating point type. Not all targets support all
5968 types however.</p>
5969
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5970<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5971 declare float @llvm.sqrt.f32(float %Val)
5972 declare double @llvm.sqrt.f64(double %Val)
5973 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5974 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5975 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5976</pre>
5977
5978<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5979<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5980 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5981 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5982 behavior for negative numbers other than -0.0 (which allows for better
5983 optimization, because there is no need to worry about errno being
5984 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]5985
5986<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5987<p>The argument and return value are floating point numbers of the same
5988 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5989
5990<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5991<p>This function returns the sqrt of the specified operand if it is a
5992 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5993
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5994</div>
5995
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5996<!-- _______________________________________________________________________ -->
5997<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5998 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5999</div>
6000
6001<div class="doc_text">
6002
6003<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6004<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6005 floating point or vector of floating point type. Not all targets support all
6006 types however.</p>
6007
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6008<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6009 declare float @llvm.powi.f32(float %Val, i32 %power)
6010 declare double @llvm.powi.f64(double %Val, i32 %power)
6011 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6012 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6013 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6014</pre>
6015
6016<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6017<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6018 specified (positive or negative) power. The order of evaluation of
6019 multiplications is not defined. When a vector of floating point type is
6020 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6021
6022<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6023<p>The second argument is an integer power, and the first is a value to raise to
6024 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6025
6026<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6027<p>This function returns the first value raised to the second power with an
6028 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6029
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6030</div>
6031
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6032<!-- _______________________________________________________________________ -->
6033<div class="doc_subsubsection">
6034 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6035</div>
6036
6037<div class="doc_text">
6038
6039<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6040<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6041 floating point or vector of floating point type. Not all targets support all
6042 types however.</p>
6043
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6044<pre>
6045 declare float @llvm.sin.f32(float %Val)
6046 declare double @llvm.sin.f64(double %Val)
6047 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6048 declare fp128 @llvm.sin.f128(fp128 %Val)
6049 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6050</pre>
6051
6052<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6053<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6054
6055<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6056<p>The argument and return value are floating point numbers of the same
6057 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6058
6059<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6060<p>This function returns the sine of the specified operand, returning the same
6061 values as the libm <tt>sin</tt> functions would, and handles error conditions
6062 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6063
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6064</div>
6065
6066<!-- _______________________________________________________________________ -->
6067<div class="doc_subsubsection">
6068 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6069</div>
6070
6071<div class="doc_text">
6072
6073<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6074<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6075 floating point or vector of floating point type. Not all targets support all
6076 types however.</p>
6077
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6078<pre>
6079 declare float @llvm.cos.f32(float %Val)
6080 declare double @llvm.cos.f64(double %Val)
6081 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6082 declare fp128 @llvm.cos.f128(fp128 %Val)
6083 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6084</pre>
6085
6086<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6087<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6088
6089<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6090<p>The argument and return value are floating point numbers of the same
6091 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6092
6093<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6094<p>This function returns the cosine of the specified operand, returning the same
6095 values as the libm <tt>cos</tt> functions would, and handles error conditions
6096 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6097
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6098</div>
6099
6100<!-- _______________________________________________________________________ -->
6101<div class="doc_subsubsection">
6102 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6103</div>
6104
6105<div class="doc_text">
6106
6107<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6108<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6109 floating point or vector of floating point type. Not all targets support all
6110 types however.</p>
6111
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6112<pre>
6113 declare float @llvm.pow.f32(float %Val, float %Power)
6114 declare double @llvm.pow.f64(double %Val, double %Power)
6115 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6116 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6117 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6118</pre>
6119
6120<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6121<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6122 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6123
6124<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6125<p>The second argument is a floating point power, and the first is a value to
6126 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6127
6128<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6129<p>This function returns the first value raised to the second power, returning
6130 the same values as the libm <tt>pow</tt> functions would, and handles error
6131 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6132
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6133</div>
6134
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6135<!-- ======================================================================= -->
6136<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6137 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6138</div>
6139
6140<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6141
6142<p>LLVM provides intrinsics for a few important bit manipulation operations.
6143 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6144
6145</div>
6146
6147<!-- _______________________________________________________________________ -->
6148<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6149 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6150</div>
6151
6152<div class="doc_text">
6153
6154<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6155<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6156 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6157
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6158<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6159 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6160 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6161 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6162</pre>
6163
6164<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6165<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6166 values with an even number of bytes (positive multiple of 16 bits). These
6167 are useful for performing operations on data that is not in the target's
6168 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6169
6170<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6171<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6172 and low byte of the input i16 swapped. Similarly,
6173 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6174 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6175 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6176 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6177 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6178 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6179
6180</div>
6181
6182<!-- _______________________________________________________________________ -->
6183<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6184 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6185</div>
6186
6187<div class="doc_text">
6188
6189<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6190<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]6191 width. Not all targets support all bit widths however.</p>
6192
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6193<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6194 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6195 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6196 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6197 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6198 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6199</pre>
6200
6201<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6202<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6203 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6204
6205<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6206<p>The only argument is the value to be counted. The argument may be of any
6207 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6208
6209<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6210<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]6211
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6212</div>
6213
6214<!-- _______________________________________________________________________ -->
6215<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6216 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6217</div>
6218
6219<div class="doc_text">
6220
6221<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6222<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6223 integer bit width. Not all targets support all bit widths however.</p>
6224
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6225<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6226 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6227 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6228 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6229 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6230 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6231</pre>
6232
6233<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6234<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6235 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6236
6237<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6238<p>The only argument is the value to be counted. The argument may be of any
6239 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6240
6241<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6242<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6243 zeros in a variable. If the src == 0 then the result is the size in bits of
6244 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6245
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6246</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6247
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6248<!-- _______________________________________________________________________ -->
6249<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6250 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6251</div>
6252
6253<div class="doc_text">
6254
6255<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6256<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6257 integer bit width. Not all targets support all bit widths however.</p>
6258
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6259<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6260 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6261 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6262 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6263 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6264 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6265</pre>
6266
6267<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6268<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6269 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6270
6271<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6272<p>The only argument is the value to be counted. The argument may be of any
6273 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6274
6275<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6276<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6277 zeros in a variable. If the src == 0 then the result is the size in bits of
6278 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6279
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6280</div>
6281
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6282<!-- ======================================================================= -->
6283<div class="doc_subsection">
6284 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6285</div>
6286
6287<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6288
6289<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6290
6291</div>
6292
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6293<!-- _______________________________________________________________________ -->
6294<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6295 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6296</div>
6297
6298<div class="doc_text">
6299
6300<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6301<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]6302 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6303
6304<pre>
6305 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6306 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6307 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6308</pre>
6309
6310<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6311<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6312 a signed addition of the two arguments, and indicate whether an overflow
6313 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6314
6315<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6316<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]6317 be of integer types of any bit width, but they must have the same bit
6318 width. The second element of the result structure must be of
6319 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6320 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6321
6322<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6323<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6324 a signed addition of the two variables. They return a structure &mdash; the
6325 first element of which is the signed summation, and the second element of
6326 which is a bit specifying if the signed summation resulted in an
6327 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6328
6329<h5>Examples:</h5>
6330<pre>
6331 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6332 %sum = extractvalue {i32, i1} %res, 0
6333 %obit = extractvalue {i32, i1} %res, 1
6334 br i1 %obit, label %overflow, label %normal
6335</pre>
6336
6337</div>
6338
6339<!-- _______________________________________________________________________ -->
6340<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6341 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6342</div>
6343
6344<div class="doc_text">
6345
6346<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6347<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]6348 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6349
6350<pre>
6351 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6352 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6353 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6354</pre>
6355
6356<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6357<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6358 an unsigned addition of the two arguments, and indicate whether a carry
6359 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6360
6361<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6362<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]6363 be of integer types of any bit width, but they must have the same bit
6364 width. The second element of the result structure must be of
6365 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6366 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6367
6368<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6369<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6370 an unsigned addition of the two arguments. They return a structure &mdash;
6371 the first element of which is the sum, and the second element of which is a
6372 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6373
6374<h5>Examples:</h5>
6375<pre>
6376 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6377 %sum = extractvalue {i32, i1} %res, 0
6378 %obit = extractvalue {i32, i1} %res, 1
6379 br i1 %obit, label %carry, label %normal
6380</pre>
6381
6382</div>
6383
6384<!-- _______________________________________________________________________ -->
6385<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6386 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6387</div>
6388
6389<div class="doc_text">
6390
6391<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6392<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]6393 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6394
6395<pre>
6396 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6397 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6398 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6399</pre>
6400
6401<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6402<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6403 a signed subtraction of the two arguments, and indicate whether an overflow
6404 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6405
6406<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6407<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]6408 be of integer types of any bit width, but they must have the same bit
6409 width. The second element of the result structure must be of
6410 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6411 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6412
6413<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6414<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6415 a signed subtraction of the two arguments. They return a structure &mdash;
6416 the first element of which is the subtraction, and the second element of
6417 which is a bit specifying if the signed subtraction resulted in an
6418 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6419
6420<h5>Examples:</h5>
6421<pre>
6422 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6423 %sum = extractvalue {i32, i1} %res, 0
6424 %obit = extractvalue {i32, i1} %res, 1
6425 br i1 %obit, label %overflow, label %normal
6426</pre>
6427
6428</div>
6429
6430<!-- _______________________________________________________________________ -->
6431<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6432 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6433</div>
6434
6435<div class="doc_text">
6436
6437<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6438<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]6439 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6440
6441<pre>
6442 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6443 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6444 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6445</pre>
6446
6447<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6448<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6449 an unsigned subtraction of the two arguments, and indicate whether an
6450 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6451
6452<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6453<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]6454 be of integer types of any bit width, but they must have the same bit
6455 width. The second element of the result structure must be of
6456 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6457 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6458
6459<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6460<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6461 an unsigned subtraction of the two arguments. They return a structure &mdash;
6462 the first element of which is the subtraction, and the second element of
6463 which is a bit specifying if the unsigned subtraction resulted in an
6464 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6465
6466<h5>Examples:</h5>
6467<pre>
6468 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6469 %sum = extractvalue {i32, i1} %res, 0
6470 %obit = extractvalue {i32, i1} %res, 1
6471 br i1 %obit, label %overflow, label %normal
6472</pre>
6473
6474</div>
6475
6476<!-- _______________________________________________________________________ -->
6477<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6478 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6479</div>
6480
6481<div class="doc_text">
6482
6483<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6484<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]6485 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6486
6487<pre>
6488 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6489 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6490 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6491</pre>
6492
6493<h5>Overview:</h5>
6494
6495<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6496 a signed multiplication of the two arguments, and indicate whether an
6497 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6498
6499<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6500<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]6501 be of integer types of any bit width, but they must have the same bit
6502 width. The second element of the result structure must be of
6503 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6504 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6505
6506<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6507<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6508 a signed multiplication of the two arguments. They return a structure &mdash;
6509 the first element of which is the multiplication, and the second element of
6510 which is a bit specifying if the signed multiplication resulted in an
6511 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6512
6513<h5>Examples:</h5>
6514<pre>
6515 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6516 %sum = extractvalue {i32, i1} %res, 0
6517 %obit = extractvalue {i32, i1} %res, 1
6518 br i1 %obit, label %overflow, label %normal
6519</pre>
6520
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6521</div>
6522
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6523<!-- _______________________________________________________________________ -->
6524<div class="doc_subsubsection">
6525 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6526</div>
6527
6528<div class="doc_text">
6529
6530<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6531<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]6532 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6533
6534<pre>
6535 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6536 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6537 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6538</pre>
6539
6540<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6541<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6542 a unsigned multiplication of the two arguments, and indicate whether an
6543 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6544
6545<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6546<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]6547 be of integer types of any bit width, but they must have the same bit
6548 width. The second element of the result structure must be of
6549 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6550 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6551
6552<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6553<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6554 an unsigned multiplication of the two arguments. They return a structure
6555 &mdash; the first element of which is the multiplication, and the second
6556 element of which is a bit specifying if the unsigned multiplication resulted
6557 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6558
6559<h5>Examples:</h5>
6560<pre>
6561 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6562 %sum = extractvalue {i32, i1} %res, 0
6563 %obit = extractvalue {i32, i1} %res, 1
6564 br i1 %obit, label %overflow, label %normal
6565</pre>
6566
6567</div>
6568
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6569<!-- ======================================================================= -->
6570<div class="doc_subsection">
6571 <a name="int_debugger">Debugger Intrinsics</a>
6572</div>
6573
6574<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6575
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6576<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6577 prefix), are described in
6578 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6579 Level Debugging</a> document.</p>
6580
6581</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6582
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6583<!-- ======================================================================= -->
6584<div class="doc_subsection">
6585 <a name="int_eh">Exception Handling Intrinsics</a>
6586</div>
6587
6588<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6589
6590<p>The LLVM exception handling intrinsics (which all start with
6591 <tt>llvm.eh.</tt> prefix), are described in
6592 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6593 Handling</a> document.</p>
6594
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6595</div>
6596
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6597<!-- ======================================================================= -->
6598<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6599 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6600</div>
6601
6602<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6603
6604<p>This intrinsic makes it possible to excise one parameter, marked with
6605 the <tt>nest</tt> attribute, from a function. The result is a callable
6606 function pointer lacking the nest parameter - the caller does not need to
6607 provide a value for it. Instead, the value to use is stored in advance in a
6608 "trampoline", a block of memory usually allocated on the stack, which also
6609 contains code to splice the nest value into the argument list. This is used
6610 to implement the GCC nested function address extension.</p>
6611
6612<p>For example, if the function is
6613 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6614 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6615 follows:</p>
6616
6617<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6618<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6619 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6620 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6621 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6622 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6623</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6624</div>
6625
6626<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6627 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6628
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6629</div>
6630
6631<!-- _______________________________________________________________________ -->
6632<div class="doc_subsubsection">
6633 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6634</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6635
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6636<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6637
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6638<h5>Syntax:</h5>
6639<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6640 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]6641</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6642
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6643<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6644<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6645 function pointer suitable for executing it.</p>
6646
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6647<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6648<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6649 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6650 sufficiently aligned block of memory; this memory is written to by the
6651 intrinsic. Note that the size and the alignment are target-specific - LLVM
6652 currently provides no portable way of determining them, so a front-end that
6653 generates this intrinsic needs to have some target-specific knowledge.
6654 The <tt>func</tt> argument must hold a function bitcast to
6655 an <tt>i8*</tt>.</p>
6656
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6657<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6658<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6659 dependent code, turning it into a function. A pointer to this function is
6660 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6661 function pointer type</a> before being called. The new function's signature
6662 is the same as that of <tt>func</tt> with any arguments marked with
6663 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6664 is allowed, and it must be of pointer type. Calling the new function is
6665 equivalent to calling <tt>func</tt> with the same argument list, but
6666 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6667 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6668 by <tt>tramp</tt> is modified, then the effect of any later call to the
6669 returned function pointer is undefined.</p>
6670
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6671</div>
6672
6673<!-- ======================================================================= -->
6674<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6675 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6676</div>
6677
6678<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6679
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6680<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6681 hardware constructs for atomic operations and memory synchronization. This
6682 provides an interface to the hardware, not an interface to the programmer. It
6683 is aimed at a low enough level to allow any programming models or APIs
6684 (Application Programming Interfaces) which need atomic behaviors to map
6685 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6686 hardware provides a "universal IR" for source languages, it also provides a
6687 starting point for developing a "universal" atomic operation and
6688 synchronization IR.</p>
6689
6690<p>These do <em>not</em> form an API such as high-level threading libraries,
6691 software transaction memory systems, atomic primitives, and intrinsic
6692 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6693 application libraries. The hardware interface provided by LLVM should allow
6694 a clean implementation of all of these APIs and parallel programming models.
6695 No one model or paradigm should be selected above others unless the hardware
6696 itself ubiquitously does so.</p>
6697
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6698</div>
6699
6700<!-- _______________________________________________________________________ -->
6701<div class="doc_subsubsection">
6702 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6703</div>
6704<div class="doc_text">
6705<h5>Syntax:</h5>
6706<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6707 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]6708</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6709
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6710<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6711<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6712 specific pairs of memory access types.</p>
6713
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6714<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6715<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6716 The first four arguments enables a specific barrier as listed below. The
6717 fith argument specifies that the barrier applies to io or device or uncached
6718 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6719
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6720<ul>
6721 <li><tt>ll</tt>: load-load barrier</li>
6722 <li><tt>ls</tt>: load-store barrier</li>
6723 <li><tt>sl</tt>: store-load barrier</li>
6724 <li><tt>ss</tt>: store-store barrier</li>
6725 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6726</ul>
6727
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6728<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6729<p>This intrinsic causes the system to enforce some ordering constraints upon
6730 the loads and stores of the program. This barrier does not
6731 indicate <em>when</em> any events will occur, it only enforces
6732 an <em>order</em> in which they occur. For any of the specified pairs of load
6733 and store operations (f.ex. load-load, or store-load), all of the first
6734 operations preceding the barrier will complete before any of the second
6735 operations succeeding the barrier begin. Specifically the semantics for each
6736 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6737
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6738<ul>
6739 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6740 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6741 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6742 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6743 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6744 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6745 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6746 load after the barrier begins.</li>
6747</ul>
6748
6749<p>These semantics are applied with a logical "and" behavior when more than one
6750 is enabled in a single memory barrier intrinsic.</p>
6751
6752<p>Backends may implement stronger barriers than those requested when they do
6753 not support as fine grained a barrier as requested. Some architectures do
6754 not need all types of barriers and on such architectures, these become
6755 noops.</p>
6756
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6757<h5>Example:</h5>
6758<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6759%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6760%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6761 store i32 4, %ptr
6762
6763%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6764 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6765 <i>; guarantee the above finishes</i>
6766 store i32 8, %ptr <i>; before this begins</i>
6767</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6768
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6769</div>
6770
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6771<!-- _______________________________________________________________________ -->
6772<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6773 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6774</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6775
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6776<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6777
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6778<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6779<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6780 any integer bit width and for different address spaces. Not all targets
6781 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6782
6783<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6784 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6785 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6786 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6787 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]6788</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6789
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6790<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6791<p>This loads a value in memory and compares it to a given value. If they are
6792 equal, it stores a new value into the memory.</p>
6793
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6794<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6795<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6796 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6797 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6798 this integer type. While any bit width integer may be used, targets may only
6799 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6800
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6801<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6802<p>This entire intrinsic must be executed atomically. It first loads the value
6803 in memory pointed to by <tt>ptr</tt> and compares it with the
6804 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6805 memory. The loaded value is yielded in all cases. This provides the
6806 equivalent of an atomic compare-and-swap operation within the SSA
6807 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6808
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6809<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6810<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6811%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6812%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6813 store i32 4, %ptr
6814
6815%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6816%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6817 <i>; yields {i32}:result1 = 4</i>
6818%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6819%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6820
6821%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6822%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6823 <i>; yields {i32}:result2 = 8</i>
6824%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6825
6826%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6827</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6828
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6829</div>
6830
6831<!-- _______________________________________________________________________ -->
6832<div class="doc_subsubsection">
6833 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6834</div>
6835<div class="doc_text">
6836<h5>Syntax:</h5>
6837
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6838<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6839 integer bit width. Not all targets support all bit widths however.</p>
6840
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6841<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6842 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6843 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6844 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6845 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]6846</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6847
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6848<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6849<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6850 the value from memory. It then stores the value in <tt>val</tt> in the memory
6851 at <tt>ptr</tt>.</p>
6852
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6853<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6854<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6855 the <tt>val</tt> argument and the result must be integers of the same bit
6856 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6857 integer type. The targets may only lower integer representations they
6858 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6859
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6860<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6861<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6862 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6863 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6864
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6865<h5>Examples:</h5>
6866<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6867%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6868%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6869 store i32 4, %ptr
6870
6871%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6872%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6873 <i>; yields {i32}:result1 = 4</i>
6874%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6875%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6876
6877%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6878%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6879 <i>; yields {i32}:result2 = 8</i>
6880
6881%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6882%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6883</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6884
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6885</div>
6886
6887<!-- _______________________________________________________________________ -->
6888<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6889 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6890
6891</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6892
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6893<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6894
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6895<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6896<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6897 any integer bit width. Not all targets support all bit widths however.</p>
6898
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6899<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6900 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6901 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6902 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6903 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]6904</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6905
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6906<h5>Overview:</h5>
6907<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6908 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6909
6910<h5>Arguments:</h5>
6911<p>The intrinsic takes two arguments, the first a pointer to an integer value
6912 and the second an integer value. The result is also an integer value. These
6913 integer types can have any bit width, but they must all have the same bit
6914 width. The targets may only lower integer representations they support.</p>
6915
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6916<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6917<p>This intrinsic does a series of operations atomically. It first loads the
6918 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6919 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]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 4, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6926%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6927 <i>; yields {i32}:result1 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6928%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6929 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6930%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6931 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6932%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6933</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6934
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6935</div>
6936
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6937<!-- _______________________________________________________________________ -->
6938<div class="doc_subsubsection">
6939 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6940
6941</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6942
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6943<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6944
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6945<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6946<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6947 any integer bit width and for different address spaces. Not all targets
6948 support all bit widths however.</p>
6949
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6950<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6951 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6952 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6953 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6954 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]6955</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6956
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6957<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6958<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6959 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6960
6961<h5>Arguments:</h5>
6962<p>The intrinsic takes two arguments, the first a pointer to an integer value
6963 and the second an integer value. The result is also an integer value. These
6964 integer types can have any bit width, but they must all have the same bit
6965 width. The targets may only lower integer representations they support.</p>
6966
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6967<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6968<p>This intrinsic does a series of operations atomically. It first loads the
6969 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6970 result to <tt>ptr</tt>. It yields the original value stored
6971 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6972
6973<h5>Examples:</h5>
6974<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6975%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6976%ptr = bitcast i8* %mallocP to i32*
6977 store i32 8, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6978%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6979 <i>; yields {i32}:result1 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6980%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6981 <i>; yields {i32}:result2 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6982%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6983 <i>; yields {i32}:result3 = 2</i>
6984%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6985</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6986
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6987</div>
6988
6989<!-- _______________________________________________________________________ -->
6990<div class="doc_subsubsection">
6991 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6992 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6993 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6994 <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]6995</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6996
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6997<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6998
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6999<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7000<p>These are overloaded intrinsics. You can
7001 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7002 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7003 bit width and for different address spaces. Not all targets support all bit
7004 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7005
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7006<pre>
7007 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7008 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7009 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7010 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]7011</pre>
7012
7013<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7014 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7015 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7016 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7017 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]7018</pre>
7019
7020<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7021 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7022 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7023 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7024 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]7025</pre>
7026
7027<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7028 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7029 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7030 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7031 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]7032</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7033
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7034<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7035<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7036 the value stored in memory at <tt>ptr</tt>. It yields the original value
7037 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7038
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7039<h5>Arguments:</h5>
7040<p>These intrinsics take two arguments, the first a pointer to an integer value
7041 and the second an integer value. The result is also an integer value. These
7042 integer types can have any bit width, but they must all have the same bit
7043 width. The targets may only lower integer representations they support.</p>
7044
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7045<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7046<p>These intrinsics does a series of operations atomically. They first load the
7047 value stored at <tt>ptr</tt>. They then do the bitwise
7048 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7049 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7050
7051<h5>Examples:</h5>
7052<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7053%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7054%ptr = bitcast i8* %mallocP to i32*
7055 store i32 0x0F0F, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7056%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7057 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7058%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7059 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7060%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7061 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7062%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7063 <i>; yields {i32}:result3 = FF</i>
7064%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7065</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7066
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7067</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7068
7069<!-- _______________________________________________________________________ -->
7070<div class="doc_subsubsection">
7071 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7072 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7073 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7074 <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]7075</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7076
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7077<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7078
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7079<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7080<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7081 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7082 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7083 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7084
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7085<pre>
7086 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7087 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7088 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7089 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]7090</pre>
7091
7092<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7093 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7094 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7095 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7096 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]7097</pre>
7098
7099<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7100 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7101 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7102 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7103 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]7104</pre>
7105
7106<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7107 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7108 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7109 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7110 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]7111</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7112
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7113<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7114<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7115 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7116 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7117
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7118<h5>Arguments:</h5>
7119<p>These intrinsics take two arguments, the first a pointer to an integer value
7120 and the second an integer value. The result is also an integer value. These
7121 integer types can have any bit width, but they must all have the same bit
7122 width. The targets may only lower integer representations they support.</p>
7123
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7124<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7125<p>These intrinsics does a series of operations atomically. They first load the
7126 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7127 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7128 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7129
7130<h5>Examples:</h5>
7131<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7132%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7133%ptr = bitcast i8* %mallocP to i32*
7134 store i32 7, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7135%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7136 <i>; yields {i32}:result0 = 7</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7137%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7138 <i>; yields {i32}:result1 = -2</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7139%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7140 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7141%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7142 <i>; yields {i32}:result3 = 8</i>
7143%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7144</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7145
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7146</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7147
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7148
7149<!-- ======================================================================= -->
7150<div class="doc_subsection">
7151 <a name="int_memorymarkers">Memory Use Markers</a>
7152</div>
7153
7154<div class="doc_text">
7155
7156<p>This class of intrinsics exists to information about the lifetime of memory
7157 objects and ranges where variables are immutable.</p>
7158
7159</div>
7160
7161<!-- _______________________________________________________________________ -->
7162<div class="doc_subsubsection">
7163 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7164</div>
7165
7166<div class="doc_text">
7167
7168<h5>Syntax:</h5>
7169<pre>
7170 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7171</pre>
7172
7173<h5>Overview:</h5>
7174<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7175 object's lifetime.</p>
7176
7177<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7178<p>The first argument is a constant integer representing the size of the
7179 object, or -1 if it is variable sized. The second argument is a pointer to
7180 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7181
7182<h5>Semantics:</h5>
7183<p>This intrinsic indicates that before this point in the code, the value of the
7184 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]7185 never be used and has an undefined value. A load from the pointer that
7186 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7187 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7188
7189</div>
7190
7191<!-- _______________________________________________________________________ -->
7192<div class="doc_subsubsection">
7193 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7194</div>
7195
7196<div class="doc_text">
7197
7198<h5>Syntax:</h5>
7199<pre>
7200 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7201</pre>
7202
7203<h5>Overview:</h5>
7204<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7205 object's lifetime.</p>
7206
7207<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7208<p>The first argument is a constant integer representing the size of the
7209 object, or -1 if it is variable sized. The second argument is a pointer to
7210 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7211
7212<h5>Semantics:</h5>
7213<p>This intrinsic indicates that after this point in the code, the value of the
7214 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7215 never be used and has an undefined value. Any stores into the memory object
7216 following this intrinsic may be removed as dead.
7217
7218</div>
7219
7220<!-- _______________________________________________________________________ -->
7221<div class="doc_subsubsection">
7222 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7223</div>
7224
7225<div class="doc_text">
7226
7227<h5>Syntax:</h5>
7228<pre>
7229 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7230</pre>
7231
7232<h5>Overview:</h5>
7233<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7234 a memory object will not change.</p>
7235
7236<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7237<p>The first argument is a constant integer representing the size of the
7238 object, or -1 if it is variable sized. The second argument is a pointer to
7239 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7240
7241<h5>Semantics:</h5>
7242<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7243 the return value, the referenced memory location is constant and
7244 unchanging.</p>
7245
7246</div>
7247
7248<!-- _______________________________________________________________________ -->
7249<div class="doc_subsubsection">
7250 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7251</div>
7252
7253<div class="doc_text">
7254
7255<h5>Syntax:</h5>
7256<pre>
7257 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7258</pre>
7259
7260<h5>Overview:</h5>
7261<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7262 a memory object are mutable.</p>
7263
7264<h5>Arguments:</h5>
7265<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7266 The second argument is a constant integer representing the size of the
7267 object, or -1 if it is variable sized and the third argument is a pointer
7268 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7269
7270<h5>Semantics:</h5>
7271<p>This intrinsic indicates that the memory is mutable again.</p>
7272
7273</div>
7274
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7275<!-- ======================================================================= -->
7276<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7277 <a name="int_general">General Intrinsics</a>
7278</div>
7279
7280<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7281
7282<p>This class of intrinsics is designed to be generic and has no specific
7283 purpose.</p>
7284
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7285</div>
7286
7287<!-- _______________________________________________________________________ -->
7288<div class="doc_subsubsection">
7289 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7290</div>
7291
7292<div class="doc_text">
7293
7294<h5>Syntax:</h5>
7295<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]7296 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]7297</pre>
7298
7299<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7300<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7301
7302<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7303<p>The first argument is a pointer to a value, the second is a pointer to a
7304 global string, the third is a pointer to a global string which is the source
7305 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7306
7307<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7308<p>This intrinsic allows annotation of local variables with arbitrary strings.
7309 This can be useful for special purpose optimizations that want to look for
7310 these annotations. These have no other defined use, they are ignored by code
7311 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7312
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7313</div>
7314
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7315<!-- _______________________________________________________________________ -->
7316<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7317 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7318</div>
7319
7320<div class="doc_text">
7321
7322<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7323<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7324 any integer bit width.</p>
7325
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7326<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]7327 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7328 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7329 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7330 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7331 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]7332</pre>
7333
7334<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7335<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7336
7337<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7338<p>The first argument is an integer value (result of some expression), the
7339 second is a pointer to a global string, the third is a pointer to a global
7340 string which is the source file name, and the last argument is the line
7341 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7342
7343<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7344<p>This intrinsic allows annotations to be put on arbitrary expressions with
7345 arbitrary strings. This can be useful for special purpose optimizations that
7346 want to look for these annotations. These have no other defined use, they
7347 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7348
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7349</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7350
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7351<!-- _______________________________________________________________________ -->
7352<div class="doc_subsubsection">
7353 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7354</div>
7355
7356<div class="doc_text">
7357
7358<h5>Syntax:</h5>
7359<pre>
7360 declare void @llvm.trap()
7361</pre>
7362
7363<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7364<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7365
7366<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7367<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7368
7369<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7370<p>This intrinsics is lowered to the target dependent trap instruction. If the
7371 target does not have a trap instruction, this intrinsic will be lowered to
7372 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7373
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7374</div>
7375
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7376<!-- _______________________________________________________________________ -->
7377<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7378 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7379</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7380
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7381<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7382
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7383<h5>Syntax:</h5>
7384<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7385 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7386</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7387
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7388<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7389<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7390 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7391 ensure that it is placed on the stack before local variables.</p>
7392
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7393<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7394<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7395 arguments. The first argument is the value loaded from the stack
7396 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7397 that has enough space to hold the value of the guard.</p>
7398
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7399<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7400<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7401 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7402 stack. This is to ensure that if a local variable on the stack is
7403 overwritten, it will destroy the value of the guard. When the function exits,
7404 the guard on the stack is checked against the original guard. If they're
7405 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7406 function.</p>
7407
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7408</div>
7409
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7410<!-- _______________________________________________________________________ -->
7411<div class="doc_subsubsection">
7412 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7413</div>
7414
7415<div class="doc_text">
7416
7417<h5>Syntax:</h5>
7418<pre>
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7419 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7420 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7421</pre>
7422
7423<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7424<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7425 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7426 operation like memcpy will either overflow a buffer that corresponds to
7427 an object, or b) to determine that a runtime check for overflow isn't
7428 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7429 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7430
7431<h5>Arguments:</h5>
7432<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7433 argument is a pointer to or into the <tt>object</tt>. The second argument
7434 is a boolean 0 or 1. This argument determines whether you want the
7435 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7436 1, variables are not allowed.</p>
7437
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7438<h5>Semantics:</h5>
7439<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7440 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7441 (depending on the <tt>type</tt> argument if the size cannot be determined
7442 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7443
7444</div>
7445
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7446<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7447<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7448<address>
7449 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7453
7454 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7455 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7456 Last modified: $Date$
7457</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7458
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7459</body>
7460</html>