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gerrit-public.fairphone.software / toolchain / llvm-project / a179e4d0a8029bb4004d92343fb2c110f77060d7 / . / 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
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame^]694 when this or the GHC convention is used.</a> This calling convention
695 does not support varargs and requires the prototype of all callees to
696 exactly match 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 Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame^]706 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
707 <dd>This calling convention has been implemented specifically for use by the
708 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
709 It passes everything in registers, going to extremes to achieve this by
710 disabling callee save registers. This calling convention should not be
711 used lightly but only for specific situations such as an alternative to
712 the <em>register pinning</em> performance technique often used when
713 implementing functional programming languages.At the moment only X86
714 supports this convention and it has the following limitations:
715 <ul>
716 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
717 floating point types are supported.</li>
718 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
719 6 floating point parameters.</li>
720 </ul>
721 This calling convention supports
722 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
723 requires both the caller and callee are using it.
724 </dd>
725
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]726 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]727 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]728 target-specific calling conventions to be used. Target specific calling
729 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]730</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]731
732<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]733 support Pascal conventions or any other well-known target-independent
734 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]735
736</div>
737
738<!-- ======================================================================= -->
739<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]740 <a name="visibility">Visibility Styles</a>
741</div>
742
743<div class="doc_text">
744
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]745<p>All Global Variables and Functions have one of the following visibility
746 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]747
748<dl>
749 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]750 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]751 that the declaration is visible to other modules and, in shared libraries,
752 means that the declared entity may be overridden. On Darwin, default
753 visibility means that the declaration is visible to other modules. Default
754 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]755
756 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]757 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]758 object if they are in the same shared object. Usually, hidden visibility
759 indicates that the symbol will not be placed into the dynamic symbol
760 table, so no other module (executable or shared library) can reference it
761 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]762
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]763 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]764 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]765 the dynamic symbol table, but that references within the defining module
766 will bind to the local symbol. That is, the symbol cannot be overridden by
767 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]768</dl>
769
770</div>
771
772<!-- ======================================================================= -->
773<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]774 <a name="namedtypes">Named Types</a>
775</div>
776
777<div class="doc_text">
778
779<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]780 it easier to read the IR and make the IR more condensed (particularly when
781 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]782
783<div class="doc_code">
784<pre>
785%mytype = type { %mytype*, i32 }
786</pre>
787</div>
788
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]789<p>You may give a name to any <a href="#typesystem">type</a> except
790 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
791 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]792
793<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]794 and that you can therefore specify multiple names for the same type. This
795 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
796 uses structural typing, the name is not part of the type. When printing out
797 LLVM IR, the printer will pick <em>one name</em> to render all types of a
798 particular shape. This means that if you have code where two different
799 source types end up having the same LLVM type, that the dumper will sometimes
800 print the "wrong" or unexpected type. This is an important design point and
801 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]802
803</div>
804
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]805<!-- ======================================================================= -->
806<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]807 <a name="globalvars">Global Variables</a>
808</div>
809
810<div class="doc_text">
811
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]812<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]813 instead of run-time. Global variables may optionally be initialized, may
814 have an explicit section to be placed in, and may have an optional explicit
815 alignment specified. A variable may be defined as "thread_local", which
816 means that it will not be shared by threads (each thread will have a
817 separated copy of the variable). A variable may be defined as a global
818 "constant," which indicates that the contents of the variable
819 will <b>never</b> be modified (enabling better optimization, allowing the
820 global data to be placed in the read-only section of an executable, etc).
821 Note that variables that need runtime initialization cannot be marked
822 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]823
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]824<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
825 constant, even if the final definition of the global is not. This capability
826 can be used to enable slightly better optimization of the program, but
827 requires the language definition to guarantee that optimizations based on the
828 'constantness' are valid for the translation units that do not include the
829 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]830
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]831<p>As SSA values, global variables define pointer values that are in scope
832 (i.e. they dominate) all basic blocks in the program. Global variables
833 always define a pointer to their "content" type because they describe a
834 region of memory, and all memory objects in LLVM are accessed through
835 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]836
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]837<p>A global variable may be declared to reside in a target-specific numbered
838 address space. For targets that support them, address spaces may affect how
839 optimizations are performed and/or what target instructions are used to
840 access the variable. The default address space is zero. The address space
841 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]842
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]843<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]844 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]845
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]846<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]847 the alignment is set to zero, the alignment of the global is set by the
848 target to whatever it feels convenient. If an explicit alignment is
849 specified, the global is forced to have at least that much alignment. All
850 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]851
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]852<p>For example, the following defines a global in a numbered address space with
853 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]854
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]855<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]856<pre>
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]857@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]858</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]859</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]860
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]861</div>
862
863
864<!-- ======================================================================= -->
865<div class="doc_subsection">
866 <a name="functionstructure">Functions</a>
867</div>
868
869<div class="doc_text">
870
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]871<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]872 optional <a href="#linkage">linkage type</a>, an optional
873 <a href="#visibility">visibility style</a>, an optional
874 <a href="#callingconv">calling convention</a>, a return type, an optional
875 <a href="#paramattrs">parameter attribute</a> for the return type, a function
876 name, a (possibly empty) argument list (each with optional
877 <a href="#paramattrs">parameter attributes</a>), optional
878 <a href="#fnattrs">function attributes</a>, an optional section, an optional
879 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
880 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]881
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]882<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
883 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]884 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]885 <a href="#callingconv">calling convention</a>, a return type, an optional
886 <a href="#paramattrs">parameter attribute</a> for the return type, a function
887 name, a possibly empty list of arguments, an optional alignment, and an
888 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]889
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]890<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]891 (Control Flow Graph) for the function. Each basic block may optionally start
892 with a label (giving the basic block a symbol table entry), contains a list
893 of instructions, and ends with a <a href="#terminators">terminator</a>
894 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]895
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]896<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]897 executed on entrance to the function, and it is not allowed to have
898 predecessor basic blocks (i.e. there can not be any branches to the entry
899 block of a function). Because the block can have no predecessors, it also
900 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]901
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]902<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]903 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]904
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]905<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]906 the alignment is set to zero, the alignment of the function is set by the
907 target to whatever it feels convenient. If an explicit alignment is
908 specified, the function is forced to have at least that much alignment. All
909 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]910
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]911<h5>Syntax:</h5>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]912<div class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]913<pre>
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]914define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]915 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
916 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
917 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
918 [<a href="#gc">gc</a>] { ... }
919</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]920</div>
921
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]922</div>
923
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]924<!-- ======================================================================= -->
925<div class="doc_subsection">
926 <a name="aliasstructure">Aliases</a>
927</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]928
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]929<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]930
931<p>Aliases act as "second name" for the aliasee value (which can be either
932 function, global variable, another alias or bitcast of global value). Aliases
933 may have an optional <a href="#linkage">linkage type</a>, and an
934 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]935
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]936<h5>Syntax:</h5>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]937<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]938<pre>
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]939@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]940</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]941</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]942
943</div>
944
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]945<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]946<div class="doc_subsection">
947 <a name="namedmetadatastructure">Named Metadata</a>
948</div>
949
950<div class="doc_text">
951
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]952<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
953 nodes</a> (but not metadata strings) and null are the only valid operands for
954 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]955
956<h5>Syntax:</h5>
957<div class="doc_code">
958<pre>
959!1 = metadata !{metadata !"one"}
960!name = !{null, !1}
961</pre>
962</div>
963
964</div>
965
966<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]967<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]968
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]969<div class="doc_text">
970
971<p>The return type and each parameter of a function type may have a set of
972 <i>parameter attributes</i> associated with them. Parameter attributes are
973 used to communicate additional information about the result or parameters of
974 a function. Parameter attributes are considered to be part of the function,
975 not of the function type, so functions with different parameter attributes
976 can have the same function type.</p>
977
978<p>Parameter attributes are simple keywords that follow the type specified. If
979 multiple parameter attributes are needed, they are space separated. For
980 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]981
982<div class="doc_code">
983<pre>
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]984declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]985declare i32 @atoi(i8 zeroext)
986declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]987</pre>
988</div>
989
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]990<p>Note that any attributes for the function result (<tt>nounwind</tt>,
991 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]992
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]993<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]994
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]995<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]996 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]997 <dd>This indicates to the code generator that the parameter or return value
998 should be zero-extended to a 32-bit value by the caller (for a parameter)
999 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1000
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1001 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1002 <dd>This indicates to the code generator that the parameter or return value
1003 should be sign-extended to a 32-bit value by the caller (for a parameter)
1004 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1005
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1006 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1007 <dd>This indicates that this parameter or return value should be treated in a
1008 special target-dependent fashion during while emitting code for a function
1009 call or return (usually, by putting it in a register as opposed to memory,
1010 though some targets use it to distinguish between two different kinds of
1011 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1012
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1014 <dd>This indicates that the pointer parameter should really be passed by value
1015 to the function. The attribute implies that a hidden copy of the pointee
1016 is made between the caller and the callee, so the callee is unable to
1017 modify the value in the callee. This attribute is only valid on LLVM
1018 pointer arguments. It is generally used to pass structs and arrays by
1019 value, but is also valid on pointers to scalars. The copy is considered
1020 to belong to the caller not the callee (for example,
1021 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1022 <tt>byval</tt> parameters). This is not a valid attribute for return
1023 values. The byval attribute also supports specifying an alignment with
1024 the align attribute. This has a target-specific effect on the code
1025 generator that usually indicates a desired alignment for the synthesized
1026 stack slot.</dd>
1027
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1028 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1029 <dd>This indicates that the pointer parameter specifies the address of a
1030 structure that is the return value of the function in the source program.
1031 This pointer must be guaranteed by the caller to be valid: loads and
1032 stores to the structure may be assumed by the callee to not to trap. This
1033 may only be applied to the first parameter. This is not a valid attribute
1034 for return values. </dd>
1035
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1036 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1037 <dd>This indicates that the pointer does not alias any global or any other
1038 parameter. The caller is responsible for ensuring that this is the
1039 case. On a function return value, <tt>noalias</tt> additionally indicates
1040 that the pointer does not alias any other pointers visible to the
1041 caller. For further details, please see the discussion of the NoAlias
1042 response in
1043 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1044 analysis</a>.</dd>
1045
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1046 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1047 <dd>This indicates that the callee does not make any copies of the pointer
1048 that outlive the callee itself. This is not a valid attribute for return
1049 values.</dd>
1050
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1051 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1052 <dd>This indicates that the pointer parameter can be excised using the
1053 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1054 attribute for return values.</dd>
1055</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1056
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1057</div>
1058
1059<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1060<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1061 <a name="gc">Garbage Collector Names</a>
1062</div>
1063
1064<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1065
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1066<p>Each function may specify a garbage collector name, which is simply a
1067 string:</p>
1068
1069<div class="doc_code">
1070<pre>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1071define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1072</pre>
1073</div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1074
1075<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1076 collector which will cause the compiler to alter its output in order to
1077 support the named garbage collection algorithm.</p>
1078
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1079</div>
1080
1081<!-- ======================================================================= -->
1082<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1083 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1084</div>
1085
1086<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1087
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1088<p>Function attributes are set to communicate additional information about a
1089 function. Function attributes are considered to be part of the function, not
1090 of the function type, so functions with different parameter attributes can
1091 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1092
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1093<p>Function attributes are simple keywords that follow the type specified. If
1094 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1095
1096<div class="doc_code">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1097<pre>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1098define void @f() noinline { ... }
1099define void @f() alwaysinline { ... }
1100define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1101define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1102</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1103</div>
1104
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1105<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1106 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1107 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1108 the backend should forcibly align the stack pointer. Specify the
1109 desired alignment, which must be a power of two, in parentheses.
1110
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1111 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1112 <dd>This attribute indicates that the inliner should attempt to inline this
1113 function into callers whenever possible, ignoring any active inlining size
1114 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1115
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1116 <dt><tt><b>inlinehint</b></tt></dt>
1117 <dd>This attribute indicates that the source code contained a hint that inlining
1118 this function is desirable (such as the "inline" keyword in C/C++). It
1119 is just a hint; it imposes no requirements on the inliner.</dd>
1120
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1121 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1122 <dd>This attribute indicates that the inliner should never inline this
1123 function in any situation. This attribute may not be used together with
1124 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1125
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1126 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1127 <dd>This attribute suggests that optimization passes and code generator passes
1128 make choices that keep the code size of this function low, and otherwise
1129 do optimizations specifically to reduce code size.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1130
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1131 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1132 <dd>This function attribute indicates that the function never returns
1133 normally. This produces undefined behavior at runtime if the function
1134 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1135
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1136 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1137 <dd>This function attribute indicates that the function never returns with an
1138 unwind or exceptional control flow. If the function does unwind, its
1139 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1140
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1141 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1142 <dd>This attribute indicates that the function computes its result (or decides
1143 to unwind an exception) based strictly on its arguments, without
1144 dereferencing any pointer arguments or otherwise accessing any mutable
1145 state (e.g. memory, control registers, etc) visible to caller functions.
1146 It does not write through any pointer arguments
1147 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1148 changes any state visible to callers. This means that it cannot unwind
1149 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1150 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1151
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1152 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1153 <dd>This attribute indicates that the function does not write through any
1154 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1155 arguments) or otherwise modify any state (e.g. memory, control registers,
1156 etc) visible to caller functions. It may dereference pointer arguments
1157 and read state that may be set in the caller. A readonly function always
1158 returns the same value (or unwinds an exception identically) when called
1159 with the same set of arguments and global state. It cannot unwind an
1160 exception by calling the <tt>C++</tt> exception throwing methods, but may
1161 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1162
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1163 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1164 <dd>This attribute indicates that the function should emit a stack smashing
1165 protector. It is in the form of a "canary"&mdash;a random value placed on
1166 the stack before the local variables that's checked upon return from the
1167 function to see if it has been overwritten. A heuristic is used to
1168 determine if a function needs stack protectors or not.<br>
1169<br>
1170 If a function that has an <tt>ssp</tt> attribute is inlined into a
1171 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1172 function will have an <tt>ssp</tt> attribute.</dd>
1173
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1174 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1175 <dd>This attribute indicates that the function should <em>always</em> emit a
1176 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1177 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1178<br>
1179 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1180 function that doesn't have an <tt>sspreq</tt> attribute or which has
1181 an <tt>ssp</tt> attribute, then the resulting function will have
1182 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1183
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1184 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1185 <dd>This attribute indicates that the code generator should not use a red
1186 zone, even if the target-specific ABI normally permits it.</dd>
1187
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1188 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1189 <dd>This attributes disables implicit floating point instructions.</dd>
1190
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1191 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1192 <dd>This attribute disables prologue / epilogue emission for the function.
1193 This can have very system-specific consequences.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1194</dl>
1195
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1196</div>
1197
1198<!-- ======================================================================= -->
1199<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1200 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1201</div>
1202
1203<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1204
1205<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1206 the GCC "file scope inline asm" blocks. These blocks are internally
1207 concatenated by LLVM and treated as a single unit, but may be separated in
1208 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1209
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1210<div class="doc_code">
1211<pre>
1212module asm "inline asm code goes here"
1213module asm "more can go here"
1214</pre>
1215</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1216
1217<p>The strings can contain any character by escaping non-printable characters.
1218 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]1219 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1220
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1221<p>The inline asm code is simply printed to the machine code .s file when
1222 assembly code is generated.</p>
1223
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1224</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1225
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1226<!-- ======================================================================= -->
1227<div class="doc_subsection">
1228 <a name="datalayout">Data Layout</a>
1229</div>
1230
1231<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1232
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1233<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1234 data is to be laid out in memory. The syntax for the data layout is
1235 simply:</p>
1236
1237<div class="doc_code">
1238<pre>
1239target datalayout = "<i>layout specification</i>"
1240</pre>
1241</div>
1242
1243<p>The <i>layout specification</i> consists of a list of specifications
1244 separated by the minus sign character ('-'). Each specification starts with
1245 a letter and may include other information after the letter to define some
1246 aspect of the data layout. The specifications accepted are as follows:</p>
1247
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1248<dl>
1249 <dt><tt>E</tt></dt>
1250 <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]1251 bits with the most significance have the lowest address location.</dd>
1252
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1253 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1254 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1255 the bits with the least significance have the lowest address
1256 location.</dd>
1257
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1258 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1259 <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]1260 <i>preferred</i> alignments. All sizes are in bits. Specifying
1261 the <i>pref</i> alignment is optional. If omitted, the
1262 preceding <tt>:</tt> should be omitted too.</dd>
1263
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1264 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1265 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1266 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1267
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1268 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1269 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1270 <i>size</i>.</dd>
1271
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1272 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1273 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1274 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1275 (double).</dd>
1276
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1277 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1278 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1279 <i>size</i>.</dd>
1280
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1281 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1282 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1283 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1284
1285 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1286 <dd>This specifies a set of native integer widths for the target CPU
1287 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1288 "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]1289 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1290 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1291</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1292
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1293<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1294 default set of specifications which are then (possibly) overriden by the
1295 specifications in the <tt>datalayout</tt> keyword. The default specifications
1296 are given in this list:</p>
1297
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1298<ul>
1299 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1300 <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]1301 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1302 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1303 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1304 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1305 <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]1306 alignment of 64-bits</li>
1307 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1308 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1309 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1310 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1311 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1312 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1313</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1314
1315<p>When LLVM is determining the alignment for a given type, it uses the
1316 following rules:</p>
1317
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1318<ol>
1319 <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]1320 specification is used.</li>
1321
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1322 <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]1323 smallest integer type that is larger than the bitwidth of the sought type
1324 is used. If none of the specifications are larger than the bitwidth then
1325 the the largest integer type is used. For example, given the default
1326 specifications above, the i7 type will use the alignment of i8 (next
1327 largest) while both i65 and i256 will use the alignment of i64 (largest
1328 specified).</li>
1329
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1330 <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]1331 largest vector type that is smaller than the sought vector type will be
1332 used as a fall back. This happens because &lt;128 x double&gt; can be
1333 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1334</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1335
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1336</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1337
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1338<!-- ======================================================================= -->
1339<div class="doc_subsection">
1340 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1341</div>
1342
1343<div class="doc_text">
1344
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1345<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1346with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1347is undefined. Pointer values are associated with address ranges
1348according to the following rules:</p>
1349
1350<ul>
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1351 <li>A pointer value formed from a
1352 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1353 is associated with the addresses associated with the first operand
1354 of the <tt>getelementptr</tt>.</li>
1355 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1356 range of the variable's storage.</li>
1357 <li>The result value of an allocation instruction is associated with
1358 the address range of the allocated storage.</li>
1359 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1360 no address.</li>
1361 <li>A pointer value formed by an
1362 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1363 address ranges of all pointer values that contribute (directly or
1364 indirectly) to the computation of the pointer's value.</li>
1365 <li>The result value of a
1366 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1367 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1368 <li>An integer constant other than zero or a pointer value returned
1369 from a function not defined within LLVM may be associated with address
1370 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1371 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1372 allocated by mechanisms provided by LLVM.</li>
1373 </ul>
1374
1375<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1376<tt><a href="#i_load">load</a></tt> merely indicates the size and
1377alignment of the memory from which to load, as well as the
1378interpretation of the value. The first operand of a
1379<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1380and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1381
1382<p>Consequently, type-based alias analysis, aka TBAA, aka
1383<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1384LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1385additional information which specialized optimization passes may use
1386to implement type-based alias analysis.</p>
1387
1388</div>
1389
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1390<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1391<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1392<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1393
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1394<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1395
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1396<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1397 intermediate representation. Being typed enables a number of optimizations
1398 to be performed on the intermediate representation directly, without having
1399 to do extra analyses on the side before the transformation. A strong type
1400 system makes it easier to read the generated code and enables novel analyses
1401 and transformations that are not feasible to perform on normal three address
1402 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1403
1404</div>
1405
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1406<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1407<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1408Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1409
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1410<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1411
1412<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1413
1414<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1415 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1416 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1417 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1418 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1419 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1420 </tr>
1421 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1422 <td><a href="#t_floating">floating point</a></td>
1423 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1424 </tr>
1425 <tr>
1426 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1427 <td><a href="#t_integer">integer</a>,
1428 <a href="#t_floating">floating point</a>,
1429 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1430 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1431 <a href="#t_struct">structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1432 <a href="#t_union">union</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1433 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1434 <a href="#t_label">label</a>,
1435 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1436 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1437 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1438 <tr>
1439 <td><a href="#t_primitive">primitive</a></td>
1440 <td><a href="#t_label">label</a>,
1441 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1442 <a href="#t_floating">floating point</a>,
1443 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1444 </tr>
1445 <tr>
1446 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1447 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1448 <a href="#t_function">function</a>,
1449 <a href="#t_pointer">pointer</a>,
1450 <a href="#t_struct">structure</a>,
1451 <a href="#t_pstruct">packed structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1452 <a href="#t_union">union</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1453 <a href="#t_vector">vector</a>,
1454 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1455 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1456 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1457 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1458</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1459
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1460<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1461 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1462 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1463
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1464</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1465
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1466<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1467<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1468
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1469<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1470
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1471<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1472 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1473
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1474</div>
1475
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1476<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1477<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1478
1479<div class="doc_text">
1480
1481<h5>Overview:</h5>
1482<p>The integer type is a very simple type that simply specifies an arbitrary
1483 bit width for the integer type desired. Any bit width from 1 bit to
1484 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1485
1486<h5>Syntax:</h5>
1487<pre>
1488 iN
1489</pre>
1490
1491<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1492 value.</p>
1493
1494<h5>Examples:</h5>
1495<table class="layout">
1496 <tr class="layout">
1497 <td class="left"><tt>i1</tt></td>
1498 <td class="left">a single-bit integer.</td>
1499 </tr>
1500 <tr class="layout">
1501 <td class="left"><tt>i32</tt></td>
1502 <td class="left">a 32-bit integer.</td>
1503 </tr>
1504 <tr class="layout">
1505 <td class="left"><tt>i1942652</tt></td>
1506 <td class="left">a really big integer of over 1 million bits.</td>
1507 </tr>
1508</table>
1509
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1510</div>
1511
1512<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1513<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1514
1515<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1516
1517<table>
1518 <tbody>
1519 <tr><th>Type</th><th>Description</th></tr>
1520 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1521 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1522 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1523 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1524 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1525 </tbody>
1526</table>
1527
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1528</div>
1529
1530<!-- _______________________________________________________________________ -->
1531<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1532
1533<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1534
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1535<h5>Overview:</h5>
1536<p>The void type does not represent any value and has no size.</p>
1537
1538<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1539<pre>
1540 void
1541</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1542
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1543</div>
1544
1545<!-- _______________________________________________________________________ -->
1546<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1547
1548<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1549
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1550<h5>Overview:</h5>
1551<p>The label type represents code labels.</p>
1552
1553<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1554<pre>
1555 label
1556</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1557
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1558</div>
1559
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1560<!-- _______________________________________________________________________ -->
1561<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1562
1563<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1564
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1565<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1566<p>The metadata type represents embedded metadata. No derived types may be
1567 created from metadata except for <a href="#t_function">function</a>
1568 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1569
1570<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1571<pre>
1572 metadata
1573</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1574
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1575</div>
1576
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1577
1578<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1579<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1580
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1581<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1582
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1583<p>The real power in LLVM comes from the derived types in the system. This is
1584 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1585 useful types. Each of these types contain one or more element types which
1586 may be a primitive type, or another derived type. For example, it is
1587 possible to have a two dimensional array, using an array as the element type
1588 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1589
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1590
1591</div>
1592
1593<!-- _______________________________________________________________________ -->
1594<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1595
1596<div class="doc_text">
1597
1598<p>Aggregate Types are a subset of derived types that can contain multiple
1599 member types. <a href="#t_array">Arrays</a>,
1600 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1601 <a href="#t_union">unions</a> are aggregate types.</p>
1602
1603</div>
1604
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1605</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1606
1607<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1608<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1609
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1610<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1611
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1612<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1613<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1614 sequentially in memory. The array type requires a size (number of elements)
1615 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1616
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1617<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1618<pre>
1619 [&lt;# elements&gt; x &lt;elementtype&gt;]
1620</pre>
1621
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1622<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1623 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1624
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1625<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1626<table class="layout">
1627 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1628 <td class="left"><tt>[40 x i32]</tt></td>
1629 <td class="left">Array of 40 32-bit integer values.</td>
1630 </tr>
1631 <tr class="layout">
1632 <td class="left"><tt>[41 x i32]</tt></td>
1633 <td class="left">Array of 41 32-bit integer values.</td>
1634 </tr>
1635 <tr class="layout">
1636 <td class="left"><tt>[4 x i8]</tt></td>
1637 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1638 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1639</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1640<p>Here are some examples of multidimensional arrays:</p>
1641<table class="layout">
1642 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1643 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1644 <td class="left">3x4 array of 32-bit integer values.</td>
1645 </tr>
1646 <tr class="layout">
1647 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1648 <td class="left">12x10 array of single precision floating point values.</td>
1649 </tr>
1650 <tr class="layout">
1651 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1652 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1653 </tr>
1654</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1655
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1656<p>There is no restriction on indexing beyond the end of the array implied by
1657 a static type (though there are restrictions on indexing beyond the bounds
1658 of an allocated object in some cases). This means that single-dimension
1659 'variable sized array' addressing can be implemented in LLVM with a zero
1660 length array type. An implementation of 'pascal style arrays' in LLVM could
1661 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1662
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1663</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1664
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1665<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1666<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1667
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1668<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1669
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1670<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1671<p>The function type can be thought of as a function signature. It consists of
1672 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]1673 function type is a scalar type, a void type, a struct type, or a union
1674 type. If the return type is a struct type then all struct elements must be
1675 of first class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1676
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1677<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1678<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1679 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1680</pre>
1681
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1682<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]1683 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1684 which indicates that the function takes a variable number of arguments.
1685 Variable argument functions can access their arguments with
1686 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1687 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1688 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1689
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1690<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1691<table class="layout">
1692 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1693 <td class="left"><tt>i32 (i32)</tt></td>
1694 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1695 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1696 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1697 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1698 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1699 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1700 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1701 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1702 </td>
1703 </tr><tr class="layout">
1704 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1705 <td class="left">A vararg function that takes at least one
1706 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1707 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1708 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1709 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1710 </tr><tr class="layout">
1711 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1712 <td class="left">A function taking an <tt>i32</tt>, returning a
1713 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1714 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1715 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1716</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1717
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1718</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1719
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1720<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1721<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1722
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1723<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1724
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1725<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1726<p>The structure type is used to represent a collection of data members together
1727 in memory. The packing of the field types is defined to match the ABI of the
1728 underlying processor. The elements of a structure may be any type that has a
1729 size.</p>
1730
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1731<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1732 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1733 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1734 Structures in registers are accessed using the
1735 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1736 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1737<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1738<pre>
1739 { &lt;type list&gt; }
1740</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1741
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1742<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1743<table class="layout">
1744 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1745 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1746 <td class="left">A triple of three <tt>i32</tt> values</td>
1747 </tr><tr class="layout">
1748 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1749 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1750 second element is a <a href="#t_pointer">pointer</a> to a
1751 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1752 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1753 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1754</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1755
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1756</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1757
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1758<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1759<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1760</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1761
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1762<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1763
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1764<h5>Overview:</h5>
1765<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1766 together in memory. There is no padding between fields. Further, the
1767 alignment of a packed structure is 1 byte. The elements of a packed
1768 structure may be any type that has a size.</p>
1769
1770<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1771 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1772 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1773
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1774<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1775<pre>
1776 &lt; { &lt;type list&gt; } &gt;
1777</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1778
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1779<h5>Examples:</h5>
1780<table class="layout">
1781 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1782 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1783 <td class="left">A triple of three <tt>i32</tt> values</td>
1784 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1785 <td class="left">
1786<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1787 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1788 second element is a <a href="#t_pointer">pointer</a> to a
1789 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1790 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1791 </tr>
1792</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1793
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1794</div>
1795
1796<!-- _______________________________________________________________________ -->
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1797<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1798
1799<div class="doc_text">
1800
1801<h5>Overview:</h5>
1802<p>A union type describes an object with size and alignment suitable for
1803 an object of any one of a given set of types (also known as an "untagged"
1804 union). It is similar in concept and usage to a
1805 <a href="#t_struct">struct</a>, except that all members of the union
1806 have an offset of zero. The elements of a union may be any type that has a
1807 size. Unions must have at least one member - empty unions are not allowed.
1808 </p>
1809
1810<p>The size of the union as a whole will be the size of its largest member,
1811 and the alignment requirements of the union as a whole will be the largest
1812 alignment requirement of any member.</p>
1813
Dan Gohman1ad14992010-02-25 16:51:31 +0000[diff] [blame]1814<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]1815 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1816 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1817 Since all members are at offset zero, the getelementptr instruction does
1818 not affect the address, only the type of the resulting pointer.</p>
1819
1820<h5>Syntax:</h5>
1821<pre>
1822 union { &lt;type list&gt; }
1823</pre>
1824
1825<h5>Examples:</h5>
1826<table class="layout">
1827 <tr class="layout">
1828 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1829 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1830 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1831 </tr><tr class="layout">
1832 <td class="left">
1833 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1834 <td class="left">A union, where the first element is a <tt>float</tt> and the
1835 second element is a <a href="#t_pointer">pointer</a> to a
1836 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1837 an <tt>i32</tt>.</td>
1838 </tr>
1839</table>
1840
1841</div>
1842
1843<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1844<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1845
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1846<div class="doc_text">
1847
1848<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1849<p>The pointer type is used to specify memory locations.
1850 Pointers are commonly used to reference objects in memory.</p>
1851
1852<p>Pointer types may have an optional address space attribute defining the
1853 numbered address space where the pointed-to object resides. The default
1854 address space is number zero. The semantics of non-zero address
1855 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1856
1857<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1858 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1859
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1860<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1861<pre>
1862 &lt;type&gt; *
1863</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1864
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1865<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1866<table class="layout">
1867 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1868 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1869 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1870 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1871 </tr>
1872 <tr class="layout">
1873 <td class="left"><tt>i32 (i32 *) *</tt></td>
1874 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1875 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1876 <tt>i32</tt>.</td>
1877 </tr>
1878 <tr class="layout">
1879 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1880 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1881 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1882 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1883</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1884
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1885</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1886
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1887<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1888<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1889
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1890<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1891
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1892<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1893<p>A vector type is a simple derived type that represents a vector of elements.
1894 Vector types are used when multiple primitive data are operated in parallel
1895 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1896 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1897 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1898
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1899<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1900<pre>
1901 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1902</pre>
1903
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1904<p>The number of elements is a constant integer value; elementtype may be any
1905 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1906
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1907<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1908<table class="layout">
1909 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1910 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1911 <td class="left">Vector of 4 32-bit integer values.</td>
1912 </tr>
1913 <tr class="layout">
1914 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1915 <td class="left">Vector of 8 32-bit floating-point values.</td>
1916 </tr>
1917 <tr class="layout">
1918 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1919 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1920 </tr>
1921</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1922
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1923</div>
1924
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1925<!-- _______________________________________________________________________ -->
1926<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1927<div class="doc_text">
1928
1929<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1930<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1931 corresponds (for example) to the C notion of a forward declared structure
1932 type. In LLVM, opaque types can eventually be resolved to any type (not just
1933 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1934
1935<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1936<pre>
1937 opaque
1938</pre>
1939
1940<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1941<table class="layout">
1942 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1943 <td class="left"><tt>opaque</tt></td>
1944 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1945 </tr>
1946</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1947
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1948</div>
1949
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1950<!-- ======================================================================= -->
1951<div class="doc_subsection">
1952 <a name="t_uprefs">Type Up-references</a>
1953</div>
1954
1955<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1956
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1957<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1958<p>An "up reference" allows you to refer to a lexically enclosing type without
1959 requiring it to have a name. For instance, a structure declaration may
1960 contain a pointer to any of the types it is lexically a member of. Example
1961 of up references (with their equivalent as named type declarations)
1962 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1963
1964<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1965 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1966 { \2 }* %y = type { %y }*
1967 \1* %z = type %z*
1968</pre>
1969
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1970<p>An up reference is needed by the asmprinter for printing out cyclic types
1971 when there is no declared name for a type in the cycle. Because the
1972 asmprinter does not want to print out an infinite type string, it needs a
1973 syntax to handle recursive types that have no names (all names are optional
1974 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1975
1976<h5>Syntax:</h5>
1977<pre>
1978 \&lt;level&gt;
1979</pre>
1980
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1981<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]1982
1983<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1984<table class="layout">
1985 <tr class="layout">
1986 <td class="left"><tt>\1*</tt></td>
1987 <td class="left">Self-referential pointer.</td>
1988 </tr>
1989 <tr class="layout">
1990 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1991 <td class="left">Recursive structure where the upref refers to the out-most
1992 structure.</td>
1993 </tr>
1994</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1995
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1996</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1997
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1998<!-- *********************************************************************** -->
1999<div class="doc_section"> <a name="constants">Constants</a> </div>
2000<!-- *********************************************************************** -->
2001
2002<div class="doc_text">
2003
2004<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2005 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2006
2007</div>
2008
2009<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]2010<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2011
2012<div class="doc_text">
2013
2014<dl>
2015 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2016 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2017 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2018
2019 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2020 <dd>Standard integers (such as '4') are constants of
2021 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2022 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2023
2024 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2025 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2026 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2027 notation (see below). The assembler requires the exact decimal value of a
2028 floating-point constant. For example, the assembler accepts 1.25 but
2029 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2030 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2031
2032 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2033 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2034 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2035</dl>
2036
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2037<p>The one non-intuitive notation for constants is the hexadecimal form of
2038 floating point constants. For example, the form '<tt>double
2039 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2040 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2041 constants are required (and the only time that they are generated by the
2042 disassembler) is when a floating point constant must be emitted but it cannot
2043 be represented as a decimal floating point number in a reasonable number of
2044 digits. For example, NaN's, infinities, and other special values are
2045 represented in their IEEE hexadecimal format so that assembly and disassembly
2046 do not cause any bits to change in the constants.</p>
2047
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2048<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2049 represented using the 16-digit form shown above (which matches the IEEE754
2050 representation for double); float values must, however, be exactly
2051 representable as IEE754 single precision. Hexadecimal format is always used
2052 for long double, and there are three forms of long double. The 80-bit format
2053 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2054 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2055 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2056 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2057 currently supported target uses this format. Long doubles will only work if
2058 they match the long double format on your target. All hexadecimal formats
2059 are big-endian (sign bit at the left).</p>
2060
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2061</div>
2062
2063<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2064<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2065<a name="aggregateconstants"></a> <!-- old anchor -->
2066<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2067</div>
2068
2069<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2070
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2071<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2072 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2073
2074<dl>
2075 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2076 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2077 type definitions (a comma separated list of elements, surrounded by braces
2078 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2079 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2080 Structure constants must have <a href="#t_struct">structure type</a>, and
2081 the number and types of elements must match those specified by the
2082 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2083
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2084 <dt><b>Union constants</b></dt>
2085 <dd>Union constants are represented with notation similar to a structure with
2086 a single element - that is, a single typed element surrounded
2087 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2088 <a href="#t_union">union type</a> can be initialized with a single-element
2089 struct as long as the type of the struct element matches the type of
2090 one of the union members.</dd>
2091
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2092 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2093 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2094 definitions (a comma separated list of elements, surrounded by square
2095 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2096 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2097 the number and types of elements must match those specified by the
2098 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2099
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2100 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2101 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2102 definitions (a comma separated list of elements, surrounded by
2103 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2104 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2105 have <a href="#t_vector">vector type</a>, and the number and types of
2106 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2107
2108 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2109 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2110 value to zero of <em>any</em> type, including scalar and
2111 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2112 This is often used to avoid having to print large zero initializers
2113 (e.g. for large arrays) and is always exactly equivalent to using explicit
2114 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2115
2116 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2117 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2118 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2119 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2120 be interpreted as part of the instruction stream, metadata is a place to
2121 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2122</dl>
2123
2124</div>
2125
2126<!-- ======================================================================= -->
2127<div class="doc_subsection">
2128 <a name="globalconstants">Global Variable and Function Addresses</a>
2129</div>
2130
2131<div class="doc_text">
2132
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2133<p>The addresses of <a href="#globalvars">global variables</a>
2134 and <a href="#functionstructure">functions</a> are always implicitly valid
2135 (link-time) constants. These constants are explicitly referenced when
2136 the <a href="#identifiers">identifier for the global</a> is used and always
2137 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2138 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2139
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2140<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2141<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2142@X = global i32 17
2143@Y = global i32 42
2144@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2145</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2146</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2147
2148</div>
2149
2150<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2151<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2152<div class="doc_text">
2153
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2154<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]2155 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2156 Undefined values may be of any type (other than label or void) and be used
2157 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2158
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2159<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2160 program is well defined no matter what value is used. This gives the
2161 compiler more freedom to optimize. Here are some examples of (potentially
2162 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2163
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2164
2165<div class="doc_code">
2166<pre>
2167 %A = add %X, undef
2168 %B = sub %X, undef
2169 %C = xor %X, undef
2170Safe:
2171 %A = undef
2172 %B = undef
2173 %C = undef
2174</pre>
2175</div>
2176
2177<p>This is safe because all of the output bits are affected by the undef bits.
2178Any output bit can have a zero or one depending on the input bits.</p>
2179
2180<div class="doc_code">
2181<pre>
2182 %A = or %X, undef
2183 %B = and %X, undef
2184Safe:
2185 %A = -1
2186 %B = 0
2187Unsafe:
2188 %A = undef
2189 %B = undef
2190</pre>
2191</div>
2192
2193<p>These logical operations have bits that are not always affected by the input.
2194For example, if "%X" has a zero bit, then the output of the 'and' operation will
2195always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2196such, 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]2197However, it is safe to assume that all bits of the undef could be 0, and
2198optimize the and to 0. Likewise, it is safe to assume that all the bits of
2199the 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]2200-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2201
2202<div class="doc_code">
2203<pre>
2204 %A = select undef, %X, %Y
2205 %B = select undef, 42, %Y
2206 %C = select %X, %Y, undef
2207Safe:
2208 %A = %X (or %Y)
2209 %B = 42 (or %Y)
2210 %C = %Y
2211Unsafe:
2212 %A = undef
2213 %B = undef
2214 %C = undef
2215</pre>
2216</div>
2217
2218<p>This set of examples show that undefined select (and conditional branch)
2219conditions can go "either way" but they have to come from one of the two
2220operands. In the %A example, if %X and %Y were both known to have a clear low
2221bit, then %A would have to have a cleared low bit. However, in the %C example,
2222the optimizer is allowed to assume that the undef operand could be the same as
2223%Y, allowing the whole select to be eliminated.</p>
2224
2225
2226<div class="doc_code">
2227<pre>
2228 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2229
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2230 %B = undef
2231 %C = xor %B, %B
2232
2233 %D = undef
2234 %E = icmp lt %D, 4
2235 %F = icmp gte %D, 4
2236
2237Safe:
2238 %A = undef
2239 %B = undef
2240 %C = undef
2241 %D = undef
2242 %E = undef
2243 %F = undef
2244</pre>
2245</div>
2246
2247<p>This example points out that two undef operands are not necessarily the same.
2248This can be surprising to people (and also matches C semantics) where they
2249assume that "X^X" is always zero, even if X is undef. This isn't true for a
2250number of reasons, but the short answer is that an undef "variable" can
2251arbitrarily change its value over its "live range". This is true because the
2252"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2253logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2254so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2255to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2256would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2257
2258<div class="doc_code">
2259<pre>
2260 %A = fdiv undef, %X
2261 %B = fdiv %X, undef
2262Safe:
2263 %A = undef
2264b: unreachable
2265</pre>
2266</div>
2267
2268<p>These examples show the crucial difference between an <em>undefined
2269value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2270allowed to have an arbitrary bit-pattern. This means that the %A operation
2271can be constant folded to undef because the undef could be an SNaN, and fdiv is
2272not (currently) defined on SNaN's. However, in the second example, we can make
2273a more aggressive assumption: because the undef is allowed to be an arbitrary
2274value, 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]2275has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2276does not execute at all. This allows us to delete the divide and all code after
2277it: since the undefined operation "can't happen", the optimizer can assume that
2278it occurs in dead code.
2279</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2280
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2281<div class="doc_code">
2282<pre>
2283a: store undef -> %X
2284b: store %X -> undef
2285Safe:
2286a: &lt;deleted&gt;
2287b: unreachable
2288</pre>
2289</div>
2290
2291<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2292can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2293overwritten with bits that happen to match what was already there. However, a
2294store "to" an undefined location could clobber arbitrary memory, therefore, it
2295has undefined behavior.</p>
2296
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2297</div>
2298
2299<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2300<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2301 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2302<div class="doc_text">
2303
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2304<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2305
2306<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2307 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2308 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2309
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2310<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2311 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2312 against null. Pointer equality tests between labels addresses is undefined
2313 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2314 equal to the null pointer. This may also be passed around as an opaque
2315 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2316 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2317 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2318
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2319<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2320 using the value as the operand to an inline assembly, but that is target
2321 specific.
2322 </p>
2323
2324</div>
2325
2326
2327<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2328<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2329</div>
2330
2331<div class="doc_text">
2332
2333<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2334 to be used as constants. Constant expressions may be of
2335 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2336 operation that does not have side effects (e.g. load and call are not
2337 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2338
2339<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2340 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2341 <dd>Truncate a constant to another type. The bit size of CST must be larger
2342 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2343
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2344 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2345 <dd>Zero extend a constant to another type. The bit size of CST must be
2346 smaller or equal to the bit size of TYPE. Both types must be
2347 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2348
2349 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2350 <dd>Sign extend a constant to another type. The bit size of CST must be
2351 smaller or equal to the bit size of TYPE. Both types must be
2352 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2353
2354 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2355 <dd>Truncate a floating point constant to another floating point type. The
2356 size of CST must be larger than the size of TYPE. Both types must be
2357 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2358
2359 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2360 <dd>Floating point extend a constant to another type. The size of CST must be
2361 smaller or equal to the size of TYPE. Both types must be floating
2362 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2363
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]2364 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2365 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2366 constant. TYPE must be a scalar or vector integer type. CST must be of
2367 scalar or vector floating point type. Both CST and TYPE must be scalars,
2368 or vectors of the same number of elements. If the value won't fit in the
2369 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2370
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2371 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2372 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2373 constant. TYPE must be a scalar or vector integer type. CST must be of
2374 scalar or vector floating point type. Both CST and TYPE must be scalars,
2375 or vectors of the same number of elements. If the value won't fit in the
2376 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2377
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2378 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2379 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2380 constant. TYPE must be a scalar or vector floating point type. CST must be
2381 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2382 vectors of the same number of elements. If the value won't fit in the
2383 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2384
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2385 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2386 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2387 constant. TYPE must be a scalar or vector floating point type. CST must be
2388 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2389 vectors of the same number of elements. If the value won't fit in the
2390 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2391
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2392 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2393 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2394 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2395 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2396 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2397
2398 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2399 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2400 type. CST must be of integer type. The CST value is zero extended,
2401 truncated, or unchanged to make it fit in a pointer size. This one is
2402 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2403
2404 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2405 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2406 are the same as those for the <a href="#i_bitcast">bitcast
2407 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2408
2409 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]2410 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2411 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2412 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2413 instruction, the index list may have zero or more indexes, which are
2414 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2415
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2416 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2417 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2418
2419 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2420 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2421
2422 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2423 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2424
2425 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2426 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2427 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2428
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]2429 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2430 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2431 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2432
2433 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2434 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2435 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2436
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2437 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2438 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2439 be any of the <a href="#binaryops">binary</a>
2440 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2441 on operands are the same as those for the corresponding instruction
2442 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2443</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2444
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2445</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2446
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2447<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2448<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2449<!-- *********************************************************************** -->
2450
2451<!-- ======================================================================= -->
2452<div class="doc_subsection">
2453<a name="inlineasm">Inline Assembler Expressions</a>
2454</div>
2455
2456<div class="doc_text">
2457
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2458<p>LLVM supports inline assembler expressions (as opposed
2459 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2460 a special value. This value represents the inline assembler as a string
2461 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2462 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2463 expression has side effects, and a flag indicating whether the function
2464 containing the asm needs to align its stack conservatively. An example
2465 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2466
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2467<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2468<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2469i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2470</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2471</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2472
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2473<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2474 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2475 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2476
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2477<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2478<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2479%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]2480</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2481</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2482
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2483<p>Inline asms with side effects not visible in the constraint list must be
2484 marked as having side effects. This is done through the use of the
2485 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2486
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2487<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2488<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2489call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2490</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2491</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2492
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2493<p>In some cases inline asms will contain code that will not work unless the
2494 stack is aligned in some way, such as calls or SSE instructions on x86,
2495 yet will not contain code that does that alignment within the asm.
2496 The compiler should make conservative assumptions about what the asm might
2497 contain and should generate its usual stack alignment code in the prologue
2498 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2499
2500<div class="doc_code">
2501<pre>
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2502call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2503</pre>
2504</div>
2505
2506<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2507 first.</p>
2508
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2509<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2510 documented here. Constraints on what can be done (e.g. duplication, moving,
2511 etc need to be documented). This is probably best done by reference to
2512 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2513
2514</div>
2515
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2516<!-- ======================================================================= -->
2517<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2518 Strings</a>
2519</div>
2520
2521<div class="doc_text">
2522
2523<p>LLVM IR allows metadata to be attached to instructions in the program that
2524 can convey extra information about the code to the optimizers and code
2525 generator. One example application of metadata is source-level debug
2526 information. There are two metadata primitives: strings and nodes. All
2527 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2528 preceding exclamation point ('<tt>!</tt>').</p>
2529
2530<p>A metadata string is a string surrounded by double quotes. It can contain
2531 any character by escaping non-printable characters with "\xx" where "xx" is
2532 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2533
2534<p>Metadata nodes are represented with notation similar to structure constants
2535 (a comma separated list of elements, surrounded by braces and preceded by an
2536 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2537 10}</tt>". Metadata nodes can have any values as their operand.</p>
2538
2539<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2540 metadata nodes, which can be looked up in the module symbol table. For
2541 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2542
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2543<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2544 function is using two metadata arguments.
2545
2546 <div class="doc_code">
2547 <pre>
2548 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2549 </pre>
2550 </div></p>
2551
2552<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2553 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2554
2555 <div class="doc_code">
2556 <pre>
2557 %indvar.next = add i64 %indvar, 1, !dbg !21
2558 </pre>
2559 </div></p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2560</div>
2561
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2562
2563<!-- *********************************************************************** -->
2564<div class="doc_section">
2565 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2566</div>
2567<!-- *********************************************************************** -->
2568
2569<p>LLVM has a number of "magic" global variables that contain data that affect
2570code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2571of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2572section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2573by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2574
2575<!-- ======================================================================= -->
2576<div class="doc_subsection">
2577<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2578</div>
2579
2580<div class="doc_text">
2581
2582<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2583href="#linkage_appending">appending linkage</a>. This array contains a list of
2584pointers to global variables and functions which may optionally have a pointer
2585cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2586
2587<pre>
2588 @X = global i8 4
2589 @Y = global i32 123
2590
2591 @llvm.used = appending global [2 x i8*] [
2592 i8* @X,
2593 i8* bitcast (i32* @Y to i8*)
2594 ], section "llvm.metadata"
2595</pre>
2596
2597<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2598compiler, assembler, and linker are required to treat the symbol as if there is
2599a reference to the global that it cannot see. For example, if a variable has
2600internal linkage and no references other than that from the <tt>@llvm.used</tt>
2601list, it cannot be deleted. This is commonly used to represent references from
2602inline asms and other things the compiler cannot "see", and corresponds to
2603"attribute((used))" in GNU C.</p>
2604
2605<p>On some targets, the code generator must emit a directive to the assembler or
2606object file to prevent the assembler and linker from molesting the symbol.</p>
2607
2608</div>
2609
2610<!-- ======================================================================= -->
2611<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2612<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2613</div>
2614
2615<div class="doc_text">
2616
2617<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2618<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2619touching the symbol. On targets that support it, this allows an intelligent
2620linker to optimize references to the symbol without being impeded as it would be
2621by <tt>@llvm.used</tt>.</p>
2622
2623<p>This is a rare construct that should only be used in rare circumstances, and
2624should not be exposed to source languages.</p>
2625
2626</div>
2627
2628<!-- ======================================================================= -->
2629<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2630<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2631</div>
2632
2633<div class="doc_text">
2634
2635<p>TODO: Describe this.</p>
2636
2637</div>
2638
2639<!-- ======================================================================= -->
2640<div class="doc_subsection">
2641<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2642</div>
2643
2644<div class="doc_text">
2645
2646<p>TODO: Describe this.</p>
2647
2648</div>
2649
2650
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2651<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2652<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2653<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2654
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2655<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2656
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2657<p>The LLVM instruction set consists of several different classifications of
2658 instructions: <a href="#terminators">terminator
2659 instructions</a>, <a href="#binaryops">binary instructions</a>,
2660 <a href="#bitwiseops">bitwise binary instructions</a>,
2661 <a href="#memoryops">memory instructions</a>, and
2662 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2663
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2664</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2665
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2666<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2667<div class="doc_subsection"> <a name="terminators">Terminator
2668Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2669
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2670<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2671
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2672<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2673 in a program ends with a "Terminator" instruction, which indicates which
2674 block should be executed after the current block is finished. These
2675 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2676 control flow, not values (the one exception being the
2677 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2678
2679<p>There are six different terminator instructions: the
2680 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2681 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2682 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2683 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2684 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2685 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2686 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2687
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2688</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2689
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2690<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2691<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2692Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2693
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2694<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2695
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2696<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2697<pre>
2698 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]2699 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2700</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2701
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2702<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2703<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2704 a value) from a function back to the caller.</p>
2705
2706<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2707 value and then causes control flow, and one that just causes control flow to
2708 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2709
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2710<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2711<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2712 return value. The type of the return value must be a
2713 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2714
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2715<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2716 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2717 value or a return value with a type that does not match its type, or if it
2718 has a void return type and contains a '<tt>ret</tt>' instruction with a
2719 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2720
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2721<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2722<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2723 the calling function's context. If the caller is a
2724 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2725 instruction after the call. If the caller was an
2726 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2727 the beginning of the "normal" destination block. If the instruction returns
2728 a value, that value shall set the call or invoke instruction's return
2729 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2730
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2731<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2732<pre>
2733 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2734 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2735 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]2736</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2737
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2738</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2739<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2740<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2741
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2742<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2743
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2744<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2745<pre>
2746 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]2747</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2748
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2749<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2750<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2751 different basic block in the current function. There are two forms of this
2752 instruction, corresponding to a conditional branch and an unconditional
2753 branch.</p>
2754
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2755<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2756<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2757 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2758 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2759 target.</p>
2760
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2761<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2762<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2763 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2764 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2765 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2766
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2767<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2768<pre>
2769Test:
2770 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2771 br i1 %cond, label %IfEqual, label %IfUnequal
2772IfEqual:
2773 <a href="#i_ret">ret</a> i32 1
2774IfUnequal:
2775 <a href="#i_ret">ret</a> i32 0
2776</pre>
2777
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2778</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2779
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2780<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2781<div class="doc_subsubsection">
2782 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2783</div>
2784
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2785<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2786
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2787<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2788<pre>
2789 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2790</pre>
2791
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2792<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2793<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]2794 several different places. It is a generalization of the '<tt>br</tt>'
2795 instruction, allowing a branch to occur to one of many possible
2796 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2797
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2798<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2799<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2800 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2801 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2802 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2803
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2804<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2805<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2806 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2807 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2808 transferred to the corresponding destination; otherwise, control flow is
2809 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2810
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2811<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2812<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2813 <tt>switch</tt> instruction, this instruction may be code generated in
2814 different ways. For example, it could be generated as a series of chained
2815 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2816
2817<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2818<pre>
2819 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2820 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2821 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2822
2823 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2824 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2825
2826 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2827 switch i32 %val, label %otherwise [ i32 0, label %onzero
2828 i32 1, label %onone
2829 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2830</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2831
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2832</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2833
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2834
2835<!-- _______________________________________________________________________ -->
2836<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2837 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2838</div>
2839
2840<div class="doc_text">
2841
2842<h5>Syntax:</h5>
2843<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2844 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]2845</pre>
2846
2847<h5>Overview:</h5>
2848
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2849<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2850 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2851 "<tt>address</tt>". Address must be derived from a <a
2852 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2853
2854<h5>Arguments:</h5>
2855
2856<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2857 rest of the arguments indicate the full set of possible destinations that the
2858 address may point to. Blocks are allowed to occur multiple times in the
2859 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2860
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2861<p>This destination list is required so that dataflow analysis has an accurate
2862 understanding of the CFG.</p>
2863
2864<h5>Semantics:</h5>
2865
2866<p>Control transfers to the block specified in the address argument. All
2867 possible destination blocks must be listed in the label list, otherwise this
2868 instruction has undefined behavior. This implies that jumps to labels
2869 defined in other functions have undefined behavior as well.</p>
2870
2871<h5>Implementation:</h5>
2872
2873<p>This is typically implemented with a jump through a register.</p>
2874
2875<h5>Example:</h5>
2876<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2877 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2878</pre>
2879
2880</div>
2881
2882
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2883<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2884<div class="doc_subsubsection">
2885 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2886</div>
2887
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2888<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2889
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2890<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2891<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2892 &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]2893 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2894</pre>
2895
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2896<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2897<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2898 function, with the possibility of control flow transfer to either the
2899 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2900 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2901 control flow will return to the "normal" label. If the callee (or any
2902 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2903 instruction, control is interrupted and continued at the dynamically nearest
2904 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2905
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2906<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2907<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2908
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2909<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2910 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2911 convention</a> the call should use. If none is specified, the call
2912 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2913
2914 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2915 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2916 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2917
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2918 <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]2919 function value being invoked. In most cases, this is a direct function
2920 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2921 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2922
2923 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2924 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2925
2926 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2927 signature argument types and parameter attributes. All arguments must be
2928 of <a href="#t_firstclass">first class</a> type. If the function
2929 signature indicates the function accepts a variable number of arguments,
2930 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2931
2932 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2933 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2934
2935 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2936 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2937
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2938 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2939 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2940 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2941</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2942
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2943<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2944<p>This instruction is designed to operate as a standard
2945 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2946 primary difference is that it establishes an association with a label, which
2947 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2948
2949<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2950 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2951 exception. Additionally, this is important for implementation of
2952 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2953
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2954<p>For the purposes of the SSA form, the definition of the value returned by the
2955 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2956 block to the "normal" label. If the callee unwinds then no return value is
2957 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]2958
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]2959<p>Note that the code generator does not yet completely support unwind, and
2960that the invoke/unwind semantics are likely to change in future versions.</p>
2961
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2962<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2963<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2964 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2965 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2966 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2967 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2968</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2969
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2970</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2971
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2972<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2973
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2974<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2975Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2976
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2977<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2978
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2979<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2980<pre>
2981 unwind
2982</pre>
2983
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2984<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2985<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2986 at the first callee in the dynamic call stack which used
2987 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2988 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2989
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2990<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2991<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2992 immediately halt. The dynamic call stack is then searched for the
2993 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2994 Once found, execution continues at the "exceptional" destination block
2995 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2996 instruction in the dynamic call chain, undefined behavior results.</p>
2997
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]2998<p>Note that the code generator does not yet completely support unwind, and
2999that the invoke/unwind semantics are likely to change in future versions.</p>
3000
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3001</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3002
3003<!-- _______________________________________________________________________ -->
3004
3005<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3006Instruction</a> </div>
3007
3008<div class="doc_text">
3009
3010<h5>Syntax:</h5>
3011<pre>
3012 unreachable
3013</pre>
3014
3015<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3016<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3017 instruction is used to inform the optimizer that a particular portion of the
3018 code is not reachable. This can be used to indicate that the code after a
3019 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3020
3021<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3022<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3023
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3024</div>
3025
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3026<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3027<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3028
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3029<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3030
3031<p>Binary operators are used to do most of the computation in a program. They
3032 require two operands of the same type, execute an operation on them, and
3033 produce a single value. The operands might represent multiple data, as is
3034 the case with the <a href="#t_vector">vector</a> data type. The result value
3035 has the same type as its operands.</p>
3036
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3037<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3038
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3039</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3040
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3041<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3042<div class="doc_subsubsection">
3043 <a name="i_add">'<tt>add</tt>' Instruction</a>
3044</div>
3045
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3046<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3047
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3048<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3049<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3050 &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]3051 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3052 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3053 &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]3054</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3055
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3056<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3057<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3058
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3059<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3060<p>The two arguments to the '<tt>add</tt>' instruction must
3061 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3062 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3063
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3064<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3065<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3066
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3067<p>If the sum has unsigned overflow, the result returned is the mathematical
3068 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]3069
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3070<p>Because LLVM integers use a two's complement representation, this instruction
3071 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3072
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3073<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3074 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3075 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
3076 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3077
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3078<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3079<pre>
3080 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3081</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3082
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3083</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3084
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3085<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3086<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3087 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3088</div>
3089
3090<div class="doc_text">
3091
3092<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3093<pre>
3094 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3095</pre>
3096
3097<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3098<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3099
3100<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3101<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3102 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3103 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3104
3105<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3106<p>The value produced is the floating point sum of the two operands.</p>
3107
3108<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3109<pre>
3110 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3111</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3112
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3113</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3114
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3115<!-- _______________________________________________________________________ -->
3116<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3117 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3118</div>
3119
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3120<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3121
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3122<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3123<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3124 &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]3125 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3126 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3127 &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]3128</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3129
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3130<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3131<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3132 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3133
3134<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3135 '<tt>neg</tt>' instruction present in most other intermediate
3136 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3137
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3138<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3139<p>The two arguments to the '<tt>sub</tt>' instruction must
3140 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3141 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3142
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3143<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3144<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3145
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3146<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3147 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3148 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3149
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3150<p>Because LLVM integers use a two's complement representation, this instruction
3151 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3152
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3153<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3154 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3155 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3156 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3157
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3158<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3159<pre>
3160 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3161 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3162</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3163
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3164</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3165
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3166<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3167<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3168 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3169</div>
3170
3171<div class="doc_text">
3172
3173<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3174<pre>
3175 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3176</pre>
3177
3178<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3179<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3180 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3181
3182<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3183 '<tt>fneg</tt>' instruction present in most other intermediate
3184 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3185
3186<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3187<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3188 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3189 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3190
3191<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3192<p>The value produced is the floating point difference of the two operands.</p>
3193
3194<h5>Example:</h5>
3195<pre>
3196 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3197 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3198</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3199
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3200</div>
3201
3202<!-- _______________________________________________________________________ -->
3203<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3204 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3205</div>
3206
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3207<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3208
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3209<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3210<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3211 &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]3212 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3213 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3214 &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]3215</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3216
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3217<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3218<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3219
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3220<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3221<p>The two arguments to the '<tt>mul</tt>' instruction must
3222 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3223 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3224
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3225<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3226<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3227
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3228<p>If the result of the multiplication has unsigned overflow, the result
3229 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3230 width of the result.</p>
3231
3232<p>Because LLVM integers use a two's complement representation, and the result
3233 is the same width as the operands, this instruction returns the correct
3234 result for both signed and unsigned integers. If a full product
3235 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3236 be sign-extended or zero-extended as appropriate to the width of the full
3237 product.</p>
3238
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3239<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3240 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3241 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3242 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3243
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3244<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3245<pre>
3246 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3247</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3248
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3249</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3250
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3251<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3252<div class="doc_subsubsection">
3253 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3254</div>
3255
3256<div class="doc_text">
3257
3258<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3259<pre>
3260 &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]3261</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3262
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3263<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3264<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3265
3266<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3267<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3268 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3269 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3270
3271<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3272<p>The value produced is the floating point product of the two operands.</p>
3273
3274<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3275<pre>
3276 &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]3277</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3278
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3279</div>
3280
3281<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3282<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3283</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3284
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3285<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3286
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3287<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3288<pre>
3289 &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]3290</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3291
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3292<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3293<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3294
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3295<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3296<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3297 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3298 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3299
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3300<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3301<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3302
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3303<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3304 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3305
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3306<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3307
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3308<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3309<pre>
3310 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3311</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3312
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3313</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3314
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3315<!-- _______________________________________________________________________ -->
3316<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3317</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3318
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3319<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3320
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3321<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3322<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3323 &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]3324 &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]3325</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3326
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3327<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3328<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3329
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3330<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3331<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3332 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3333 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3334
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3335<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3336<p>The value produced is the signed integer quotient of the two operands rounded
3337 towards zero.</p>
3338
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3339<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3340 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3341
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3342<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3343 undefined behavior; this is a rare case, but can occur, for example, by doing
3344 a 32-bit division of -2147483648 by -1.</p>
3345
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3346<p>If the <tt>exact</tt> keyword is present, the result value of the
3347 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3348 would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3349
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3350<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3351<pre>
3352 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3353</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3354
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3355</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3356
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3357<!-- _______________________________________________________________________ -->
3358<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3359Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3360
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3361<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3362
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3363<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3364<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3365 &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]3366</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3367
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3368<h5>Overview:</h5>
3369<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3370
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3371<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3372<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3373 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3374 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3375
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3376<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3377<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3378
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3379<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3380<pre>
3381 &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]3382</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3383
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3384</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3385
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3386<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3387<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3388</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3389
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3390<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3391
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3392<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3393<pre>
3394 &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]3395</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3396
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3397<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3398<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3399 division of its two arguments.</p>
3400
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3401<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3402<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3403 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3404 values. Both arguments must have identical types.</p>
3405
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3406<h5>Semantics:</h5>
3407<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3408 This instruction always performs an unsigned division to get the
3409 remainder.</p>
3410
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3411<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3412 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3413
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3414<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3415
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3416<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3417<pre>
3418 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3419</pre>
3420
3421</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3422
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3423<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3424<div class="doc_subsubsection">
3425 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3426</div>
3427
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3428<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3429
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3430<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3431<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3432 &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]3433</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3434
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3435<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3436<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3437 division of its two operands. This instruction can also take
3438 <a href="#t_vector">vector</a> versions of the values in which case the
3439 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3440
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3441<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3442<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3443 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3444 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3445
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3446<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3447<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3448 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3449 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3450 a value. For more information about the difference,
3451 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3452 Math Forum</a>. For a table of how this is implemented in various languages,
3453 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3454 Wikipedia: modulo operation</a>.</p>
3455
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3456<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3457 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3458
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3459<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3460 Overflow also leads to undefined behavior; this is a rare case, but can
3461 occur, for example, by taking the remainder of a 32-bit division of
3462 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3463 lets srem be implemented using instructions that return both the result of
3464 the division and the remainder.)</p>
3465
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3466<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3467<pre>
3468 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3469</pre>
3470
3471</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3472
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3473<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3474<div class="doc_subsubsection">
3475 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3476
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3477<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3478
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3479<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3480<pre>
3481 &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]3482</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3483
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3484<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3485<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3486 its two operands.</p>
3487
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3488<h5>Arguments:</h5>
3489<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3490 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3491 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3492
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3493<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3494<p>This instruction returns the <i>remainder</i> of a division. The remainder
3495 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3496
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3497<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3498<pre>
3499 &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]3500</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3501
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3502</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3503
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3504<!-- ======================================================================= -->
3505<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3506Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3507
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3508<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3509
3510<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3511 program. They are generally very efficient instructions and can commonly be
3512 strength reduced from other instructions. They require two operands of the
3513 same type, execute an operation on them, and produce a single value. The
3514 resulting value is the same type as its operands.</p>
3515
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3516</div>
3517
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3518<!-- _______________________________________________________________________ -->
3519<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3520Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3521
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3522<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3523
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3524<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3525<pre>
3526 &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]3527</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3528
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3529<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3530<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3531 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3532
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3533<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3534<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3535 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3536 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3537
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3538<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3539<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3540 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3541 is (statically or dynamically) negative or equal to or larger than the number
3542 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3543 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3544 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3545
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3546<h5>Example:</h5>
3547<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3548 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3549 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3550 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3551 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3552 &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]3553</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3554
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3555</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3556
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3557<!-- _______________________________________________________________________ -->
3558<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3559Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3560
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3561<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3562
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3563<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3564<pre>
3565 &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]3566</pre>
3567
3568<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3569<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3570 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3571
3572<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3573<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3574 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3575 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3576
3577<h5>Semantics:</h5>
3578<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3579 significant bits of the result will be filled with zero bits after the shift.
3580 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3581 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3582 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3583 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3584
3585<h5>Example:</h5>
3586<pre>
3587 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3588 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3589 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3590 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3591 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3592 &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]3593</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3594
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3595</div>
3596
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3597<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3598<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3599Instruction</a> </div>
3600<div class="doc_text">
3601
3602<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3603<pre>
3604 &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]3605</pre>
3606
3607<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3608<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3609 operand shifted to the right a specified number of bits with sign
3610 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3611
3612<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3613<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3614 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3615 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3616
3617<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3618<p>This instruction always performs an arithmetic shift right operation, The
3619 most significant bits of the result will be filled with the sign bit
3620 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3621 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3622 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3623 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3624
3625<h5>Example:</h5>
3626<pre>
3627 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3628 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3629 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3630 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3631 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3632 &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]3633</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3634
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3635</div>
3636
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3637<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3638<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3639Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3640
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3641<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3642
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3643<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3644<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3645 &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]3646</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3647
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3648<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3649<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3650 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3651
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3652<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3653<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3654 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3655 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3656
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3657<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3658<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3659
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3660<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3661 <tbody>
3662 <tr>
3663 <td>In0</td>
3664 <td>In1</td>
3665 <td>Out</td>
3666 </tr>
3667 <tr>
3668 <td>0</td>
3669 <td>0</td>
3670 <td>0</td>
3671 </tr>
3672 <tr>
3673 <td>0</td>
3674 <td>1</td>
3675 <td>0</td>
3676 </tr>
3677 <tr>
3678 <td>1</td>
3679 <td>0</td>
3680 <td>0</td>
3681 </tr>
3682 <tr>
3683 <td>1</td>
3684 <td>1</td>
3685 <td>1</td>
3686 </tr>
3687 </tbody>
3688</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3689
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3690<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3691<pre>
3692 &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]3693 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3694 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3695</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3696</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3697<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3698<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3699
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3700<div class="doc_text">
3701
3702<h5>Syntax:</h5>
3703<pre>
3704 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3705</pre>
3706
3707<h5>Overview:</h5>
3708<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3709 two operands.</p>
3710
3711<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3712<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3713 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3714 values. Both arguments must have identical types.</p>
3715
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3716<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3717<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3718
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3719<table border="1" cellspacing="0" cellpadding="4">
3720 <tbody>
3721 <tr>
3722 <td>In0</td>
3723 <td>In1</td>
3724 <td>Out</td>
3725 </tr>
3726 <tr>
3727 <td>0</td>
3728 <td>0</td>
3729 <td>0</td>
3730 </tr>
3731 <tr>
3732 <td>0</td>
3733 <td>1</td>
3734 <td>1</td>
3735 </tr>
3736 <tr>
3737 <td>1</td>
3738 <td>0</td>
3739 <td>1</td>
3740 </tr>
3741 <tr>
3742 <td>1</td>
3743 <td>1</td>
3744 <td>1</td>
3745 </tr>
3746 </tbody>
3747</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3748
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3749<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3750<pre>
3751 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3752 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3753 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3754</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3755
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3756</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3757
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3758<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3759<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3760Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3761
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3762<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3763
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3764<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3765<pre>
3766 &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]3767</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3768
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3769<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3770<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3771 its two operands. The <tt>xor</tt> is used to implement the "one's
3772 complement" operation, which is the "~" operator in C.</p>
3773
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3774<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3775<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3776 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3777 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3778
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3779<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3780<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3781
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3782<table border="1" cellspacing="0" cellpadding="4">
3783 <tbody>
3784 <tr>
3785 <td>In0</td>
3786 <td>In1</td>
3787 <td>Out</td>
3788 </tr>
3789 <tr>
3790 <td>0</td>
3791 <td>0</td>
3792 <td>0</td>
3793 </tr>
3794 <tr>
3795 <td>0</td>
3796 <td>1</td>
3797 <td>1</td>
3798 </tr>
3799 <tr>
3800 <td>1</td>
3801 <td>0</td>
3802 <td>1</td>
3803 </tr>
3804 <tr>
3805 <td>1</td>
3806 <td>1</td>
3807 <td>0</td>
3808 </tr>
3809 </tbody>
3810</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3811
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3812<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3813<pre>
3814 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3815 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3816 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3817 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3818</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3819
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3820</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3821
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3822<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3823<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3824 <a name="vectorops">Vector Operations</a>
3825</div>
3826
3827<div class="doc_text">
3828
3829<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3830 target-independent manner. These instructions cover the element-access and
3831 vector-specific operations needed to process vectors effectively. While LLVM
3832 does directly support these vector operations, many sophisticated algorithms
3833 will want to use target-specific intrinsics to take full advantage of a
3834 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3835
3836</div>
3837
3838<!-- _______________________________________________________________________ -->
3839<div class="doc_subsubsection">
3840 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3841</div>
3842
3843<div class="doc_text">
3844
3845<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3846<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3847 &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]3848</pre>
3849
3850<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3851<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3852 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3853
3854
3855<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3856<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3857 of <a href="#t_vector">vector</a> type. The second operand is an index
3858 indicating the position from which to extract the element. The index may be
3859 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3860
3861<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3862<p>The result is a scalar of the same type as the element type of
3863 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3864 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3865 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3866
3867<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3868<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3869 &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]3870</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3871
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3872</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3873
3874<!-- _______________________________________________________________________ -->
3875<div class="doc_subsubsection">
3876 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3877</div>
3878
3879<div class="doc_text">
3880
3881<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3882<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]3883 &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]3884</pre>
3885
3886<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3887<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3888 vector at a specified index.</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 operand of an '<tt>insertelement</tt>' instruction is a value
3892 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3893 whose type must equal the element type of the first operand. The third
3894 operand is an index indicating the position at which to insert the value.
3895 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3896
3897<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3898<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3899 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3900 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3901 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3902
3903<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3904<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3905 &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]3906</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3907
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3908</div>
3909
3910<!-- _______________________________________________________________________ -->
3911<div class="doc_subsubsection">
3912 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3913</div>
3914
3915<div class="doc_text">
3916
3917<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3918<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]3919 &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]3920</pre>
3921
3922<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3923<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3924 from two input vectors, returning a vector with the same element type as the
3925 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3926
3927<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3928<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3929 with types that match each other. The third argument is a shuffle mask whose
3930 element type is always 'i32'. The result of the instruction is a vector
3931 whose length is the same as the shuffle mask and whose element type is the
3932 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3933
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3934<p>The shuffle mask operand is required to be a constant vector with either
3935 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3936
3937<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3938<p>The elements of the two input vectors are numbered from left to right across
3939 both of the vectors. The shuffle mask operand specifies, for each element of
3940 the result vector, which element of the two input vectors the result element
3941 gets. The element selector may be undef (meaning "don't care") and the
3942 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3943
3944<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3945<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3946 &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]3947 &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]3948 &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]3949 &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]3950 &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]3951 &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]3952 &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]3953 &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]3954</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3955
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3956</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]3957
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3958<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3959<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3960 <a name="aggregateops">Aggregate Operations</a>
3961</div>
3962
3963<div class="doc_text">
3964
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3965<p>LLVM supports several instructions for working with
3966 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3967
3968</div>
3969
3970<!-- _______________________________________________________________________ -->
3971<div class="doc_subsubsection">
3972 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3973</div>
3974
3975<div class="doc_text">
3976
3977<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3978<pre>
3979 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3980</pre>
3981
3982<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3983<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
3984 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3985
3986<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3987<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3988 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
3989 <a href="#t_array">array</a> type. The operands are constant indices to
3990 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3991 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</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 the value at the position in the aggregate specified by the
3995 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3996
3997<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3998<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3999 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4000</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4001
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4002</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4003
4004<!-- _______________________________________________________________________ -->
4005<div class="doc_subsubsection">
4006 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4007</div>
4008
4009<div class="doc_text">
4010
4011<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4012<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4013 &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]4014</pre>
4015
4016<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4017<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4018 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4019
4020<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4021<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4022 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4023 <a href="#t_array">array</a> type. The second operand is a first-class
4024 value to insert. The following operands are constant indices indicating
4025 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]4026 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4027 value to insert must have the same type as the value identified by the
4028 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4029
4030<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4031<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4032 that of <tt>val</tt> except that the value at the position specified by the
4033 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4034
4035<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4036<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4037 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4038 %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]4039</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4040
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4041</div>
4042
4043
4044<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4045<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4046 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4047</div>
4048
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4049<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4050
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4051<p>A key design point of an SSA-based representation is how it represents
4052 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4053 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4054 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4055
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4056</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4057
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4058<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4059<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4060 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4061</div>
4062
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4063<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4064
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4065<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4066<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4067 &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]4068</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4069
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4070<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4071<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4072 currently executing function, to be automatically released when this function
4073 returns to its caller. The object is always allocated in the generic address
4074 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4075
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4076<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4077<p>The '<tt>alloca</tt>' instruction
4078 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4079 runtime stack, returning a pointer of the appropriate type to the program.
4080 If "NumElements" is specified, it is the number of elements allocated,
4081 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4082 specified, the value result of the allocation is guaranteed to be aligned to
4083 at least that boundary. If not specified, or if zero, the target can choose
4084 to align the allocation on any convenient boundary compatible with the
4085 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4086
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4087<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4088
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4089<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4090<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4091 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4092 memory is automatically released when the function returns. The
4093 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4094 variables that must have an address available. When the function returns
4095 (either with the <tt><a href="#i_ret">ret</a></tt>
4096 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4097 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4098
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4099<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4100<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4101 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4102 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4103 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4104 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4105</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4106
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4107</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4108
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4109<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4110<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4111Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4112
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4113<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4114
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4115<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4116<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4117 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4118 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4119 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4120</pre>
4121
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4122<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4123<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4124
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4125<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4126<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4127 from which to load. The pointer must point to
4128 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4129 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
4130 number or order of execution of this <tt>load</tt> with other
4131 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4132 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4133
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4134<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4135 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4136 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4137 alignment for the target. It is the responsibility of the code emitter to
4138 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4139 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4140 produce less efficient code. An alignment of 1 is always safe.</p>
4141
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4142<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4143 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4144 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4145 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4146 and code generator that this load is not expected to be reused in the cache.
4147 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4148 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4149
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4150<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4151<p>The location of memory pointed to is loaded. If the value being loaded is of
4152 scalar type then the number of bytes read does not exceed the minimum number
4153 of bytes needed to hold all bits of the type. For example, loading an
4154 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4155 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4156 is undefined if the value was not originally written using a store of the
4157 same type.</p>
4158
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4159<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4160<pre>
4161 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4162 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4163 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4164</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4165
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4166</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4167
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4168<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4169<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4170Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4171
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4172<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4173
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4174<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4175<pre>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4176 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4177 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]4178</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4179
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4180<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4181<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4182
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4183<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4184<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4185 and an address at which to store it. The type of the
4186 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4187 the <a href="#t_firstclass">first class</a> type of the
4188 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4189 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4190 or order of execution of this <tt>store</tt> with other
4191 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4192 instructions.</p>
4193
4194<p>The optional constant "align" argument specifies the alignment of the
4195 operation (that is, the alignment of the memory address). A value of 0 or an
4196 omitted "align" argument means that the operation has the preferential
4197 alignment for the target. It is the responsibility of the code emitter to
4198 ensure that the alignment information is correct. Overestimating the
4199 alignment results in an undefined behavior. Underestimating the alignment may
4200 produce less efficient code. An alignment of 1 is always safe.</p>
4201
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4202<p>The optional !nontemporal metadata must reference a single metatadata
4203 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4204 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4205 instruction tells the optimizer and code generator that this load is
4206 not expected to be reused in the cache. The code generator may
4207 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4208 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4209
4210
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4211<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4212<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4213 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4214 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4215 does not exceed the minimum number of bytes needed to hold all bits of the
4216 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4217 writing a value of a type like <tt>i20</tt> with a size that is not an
4218 integral number of bytes, it is unspecified what happens to the extra bits
4219 that do not belong to the type, but they will typically be overwritten.</p>
4220
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4221<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4222<pre>
4223 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4224 store i32 3, i32* %ptr <i>; yields {void}</i>
4225 %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]4226</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4227
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4228</div>
4229
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4230<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4231<div class="doc_subsubsection">
4232 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4233</div>
4234
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4235<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4236
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4237<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4238<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4239 &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]4240 &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]4241</pre>
4242
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4243<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4244<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4245 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4246 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4247
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4248<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4249<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4250 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4251 elements of the aggregate object are indexed. The interpretation of each
4252 index is dependent on the type being indexed into. The first index always
4253 indexes the pointer value given as the first argument, the second index
4254 indexes a value of the type pointed to (not necessarily the value directly
4255 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4256 indexed into must be a pointer value, subsequent types can be arrays,
4257 vectors, structs and unions. Note that subsequent types being indexed into
4258 can never be pointers, since that would require loading the pointer before
4259 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4260
4261<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]4262 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4263 integer <b>constants</b> are allowed. When indexing into an array, pointer
4264 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]4265 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4266
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4267<p>For example, let's consider a C code fragment and how it gets compiled to
4268 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4269
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4270<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4271<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4272struct RT {
4273 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4274 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4275 char C;
4276};
4277struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4278 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4279 double Y;
4280 struct RT Z;
4281};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4282
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4283int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4284 return &amp;s[1].Z.B[5][13];
4285}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4286</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4287</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4288
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4289<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4290
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4291<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4292<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4293%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4294%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4295
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4296define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4297entry:
4298 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4299 ret i32* %reg
4300}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4301</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4302</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4303
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4304<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4305<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]4306 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4307 }</tt>' type, a structure. The second index indexes into the third element
4308 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4309 i8 }</tt>' type, another structure. The third index indexes into the second
4310 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4311 array. The two dimensions of the array are subscripted into, yielding an
4312 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4313 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4314
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4315<p>Note that it is perfectly legal to index partially through a structure,
4316 returning a pointer to an inner element. Because of this, the LLVM code for
4317 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4318
4319<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4320 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4321 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4322 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4323 %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]4324 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4325 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4326 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4327 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4328</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4329
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4330<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4331 <tt>getelementptr</tt> is undefined if the base pointer is not an
4332 <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]4333 that would be formed by successive addition of the offsets implied by the
4334 indices to the base address with infinitely precise arithmetic are not an
4335 <i>in bounds</i> address of that allocated object.
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4336 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohman2de532c2009-08-20 17:08:17 +0000[diff] [blame]4337 that point into the object, plus the address one byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4338
4339<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4340 the base address with silently-wrapping two's complement arithmetic, and
4341 the result value of the <tt>getelementptr</tt> may be outside the object
4342 pointed to by the base pointer. The result value may not necessarily be
4343 used to access memory though, even if it happens to point into allocated
4344 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4345 section for more information.</p>
4346
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4347<p>The getelementptr instruction is often confusing. For some more insight into
4348 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4349
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4350<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4351<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4352 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4353 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4354 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4355 %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]4356 <i>; yields i8*:eptr</i>
4357 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4358 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4359 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4360</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4361
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4362</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4363
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4364<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4365<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4366</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4367
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4368<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4369
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4370<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4371 which all take a single operand and a type. They perform various bit
4372 conversions on the operand.</p>
4373
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4374</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4375
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4376<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4377<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4378 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4379</div>
4380<div class="doc_text">
4381
4382<h5>Syntax:</h5>
4383<pre>
4384 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4385</pre>
4386
4387<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4388<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4389 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4390
4391<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4392<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4393 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4394 size and type of the result, which must be
4395 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4396 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4397 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4398
4399<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4400<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4401 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4402 source size must be larger than the destination size, <tt>trunc</tt> cannot
4403 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4404
4405<h5>Example:</h5>
4406<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4407 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4408 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4409 %Z = trunc i32 122 to i1 <i>; yields i1:false</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_zext">'<tt>zext .. to</tt>' Instruction</a>
4417</div>
4418<div class="doc_text">
4419
4420<h5>Syntax:</h5>
4421<pre>
4422 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4423</pre>
4424
4425<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4426<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4427 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4428
4429
4430<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4431<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]4432 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4433 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]4434 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4435 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4436
4437<h5>Semantics:</h5>
4438<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]4439 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4440
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4441<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]4442
4443<h5>Example:</h5>
4444<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4445 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4446 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4447</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4448
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4449</div>
4450
4451<!-- _______________________________________________________________________ -->
4452<div class="doc_subsubsection">
4453 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4454</div>
4455<div class="doc_text">
4456
4457<h5>Syntax:</h5>
4458<pre>
4459 &lt;result&gt; = sext &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>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4464
4465<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4466<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]4467 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4468 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]4469 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4470 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4471
4472<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4473<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4474 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4475 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4476
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4477<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]4478
4479<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4480<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4481 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4482 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4483</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4484
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4485</div>
4486
4487<!-- _______________________________________________________________________ -->
4488<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4489 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4490</div>
4491
4492<div class="doc_text">
4493
4494<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4495<pre>
4496 &lt;result&gt; = fptrunc &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>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4501 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4502
4503<h5>Arguments:</h5>
4504<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4505 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4506 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]4507 <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]4508 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4509
4510<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4511<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4512 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4513 <a href="#t_floating">floating point</a> type. If the value cannot fit
4514 within the destination type, <tt>ty2</tt>, then the results are
4515 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4516
4517<h5>Example:</h5>
4518<pre>
4519 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4520 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4521</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4522
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4523</div>
4524
4525<!-- _______________________________________________________________________ -->
4526<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4527 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4528</div>
4529<div class="doc_text">
4530
4531<h5>Syntax:</h5>
4532<pre>
4533 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4534</pre>
4535
4536<h5>Overview:</h5>
4537<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]4538 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4539
4540<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4541<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4542 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4543 a <a href="#t_floating">floating point</a> type to cast it to. The source
4544 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4545
4546<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4547<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4548 <a href="#t_floating">floating point</a> type to a larger
4549 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4550 used to make a <i>no-op cast</i> because it always changes bits. Use
4551 <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]4552
4553<h5>Example:</h5>
4554<pre>
4555 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4556 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
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 Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4563 <a name="i_fptoui">'<tt>fptoui .. 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 Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4569 &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]4570</pre>
4571
4572<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4573<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4574 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4575
4576<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4577<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4578 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4579 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4580 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4581 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4582
4583<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4584<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4585 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4586 towards zero) unsigned integer value. If the value cannot fit
4587 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4588
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4589<h5>Example:</h5>
4590<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4591 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4592 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4593 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4594</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4595
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4596</div>
4597
4598<!-- _______________________________________________________________________ -->
4599<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4600 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4601</div>
4602<div class="doc_text">
4603
4604<h5>Syntax:</h5>
4605<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4606 &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]4607</pre>
4608
4609<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4610<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4611 <a href="#t_floating">floating point</a> <tt>value</tt> to
4612 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4613
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4614<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4615<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4616 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4617 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4618 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4619 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4620
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4621<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4622<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4623 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4624 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4625 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4626
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4627<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4628<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4629 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4630 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4631 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4632</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4633
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4634</div>
4635
4636<!-- _______________________________________________________________________ -->
4637<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4638 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4639</div>
4640<div class="doc_text">
4641
4642<h5>Syntax:</h5>
4643<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4644 &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]4645</pre>
4646
4647<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4648<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4649 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4650
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4651<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4652<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]4653 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4654 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4655 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4656 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4657
4658<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4659<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4660 integer quantity and converts it to the corresponding floating point
4661 value. If the value cannot fit in the floating point value, the results are
4662 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4663
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4664<h5>Example:</h5>
4665<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4666 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4667 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4668</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4669
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4670</div>
4671
4672<!-- _______________________________________________________________________ -->
4673<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4674 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4675</div>
4676<div class="doc_text">
4677
4678<h5>Syntax:</h5>
4679<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4680 &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]4681</pre>
4682
4683<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4684<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4685 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4686
4687<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4688<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]4689 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4690 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4691 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4692 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4693
4694<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4695<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4696 quantity and converts it to the corresponding floating point value. If the
4697 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4698
4699<h5>Example:</h5>
4700<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4701 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4702 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4703</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4704
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4705</div>
4706
4707<!-- _______________________________________________________________________ -->
4708<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4709 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4710</div>
4711<div class="doc_text">
4712
4713<h5>Syntax:</h5>
4714<pre>
4715 &lt;result&gt; = ptrtoint &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>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4720 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4721
4722<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4723<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4724 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4725 <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]4726
4727<h5>Semantics:</h5>
4728<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4729 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4730 truncating or zero extending that value to the size of the integer type. If
4731 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4732 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4733 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4734 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4735
4736<h5>Example:</h5>
4737<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4738 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4739 %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]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">
4746 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4747</div>
4748<div class="doc_text">
4749
4750<h5>Syntax:</h5>
4751<pre>
4752 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4753</pre>
4754
4755<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4756<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4757 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4758
4759<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4760<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4761 value to cast, and a type to cast it to, which must be a
4762 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4763
4764<h5>Semantics:</h5>
4765<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4766 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4767 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4768 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4769 than the size of a pointer then a zero extension is done. If they are the
4770 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4771
4772<h5>Example:</h5>
4773<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4774 %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]4775 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4776 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4777</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4778
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4779</div>
4780
4781<!-- _______________________________________________________________________ -->
4782<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4783 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4784</div>
4785<div class="doc_text">
4786
4787<h5>Syntax:</h5>
4788<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4789 &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]4790</pre>
4791
4792<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4793<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4794 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4795
4796<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4797<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4798 non-aggregate first class value, and a type to cast it to, which must also be
4799 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4800 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4801 identical. If the source type is a pointer, the destination type must also be
4802 a pointer. This instruction supports bitwise conversion of vectors to
4803 integers and to vectors of other types (as long as they have the same
4804 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4805
4806<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4807<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4808 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4809 this conversion. The conversion is done as if the <tt>value</tt> had been
4810 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4811 be converted to other pointer types with this instruction. To convert
4812 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4813 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4814
4815<h5>Example:</h5>
4816<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4817 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4818 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4819 %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]4820</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4821
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4822</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4823
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4824<!-- ======================================================================= -->
4825<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4826
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4827<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4828
4829<p>The instructions in this category are the "miscellaneous" instructions, which
4830 defy better classification.</p>
4831
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4832</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4833
4834<!-- _______________________________________________________________________ -->
4835<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4836</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4837
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4838<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4839
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4840<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4841<pre>
4842 &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]4843</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4844
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4845<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4846<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4847 boolean values based on comparison of its two integer, integer vector, or
4848 pointer operands.</p>
4849
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4850<h5>Arguments:</h5>
4851<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4852 the condition code indicating the kind of comparison to perform. It is not a
4853 value, just a keyword. The possible condition code are:</p>
4854
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4855<ol>
4856 <li><tt>eq</tt>: equal</li>
4857 <li><tt>ne</tt>: not equal </li>
4858 <li><tt>ugt</tt>: unsigned greater than</li>
4859 <li><tt>uge</tt>: unsigned greater or equal</li>
4860 <li><tt>ult</tt>: unsigned less than</li>
4861 <li><tt>ule</tt>: unsigned less or equal</li>
4862 <li><tt>sgt</tt>: signed greater than</li>
4863 <li><tt>sge</tt>: signed greater or equal</li>
4864 <li><tt>slt</tt>: signed less than</li>
4865 <li><tt>sle</tt>: signed less or equal</li>
4866</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4867
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]4868<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4869 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4870 typed. They must also be identical types.</p>
4871
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4872<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4873<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4874 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4875 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]4876 result, as follows:</p>
4877
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4878<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4879 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4880 <tt>false</tt> otherwise. No sign interpretation is necessary or
4881 performed.</li>
4882
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4883 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4884 <tt>false</tt> otherwise. No sign interpretation is necessary or
4885 performed.</li>
4886
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4887 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4888 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4889
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4890 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4891 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4892 to <tt>op2</tt>.</li>
4893
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4894 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4895 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4896
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4897 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4898 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4899
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4900 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4901 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4902
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4903 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4904 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4905 to <tt>op2</tt>.</li>
4906
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4907 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4908 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4909
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4910 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4911 <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]4912</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4913
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4914<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4915 values are compared as if they were integers.</p>
4916
4917<p>If the operands are integer vectors, then they are compared element by
4918 element. The result is an <tt>i1</tt> vector with the same number of elements
4919 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4920
4921<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4922<pre>
4923 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4924 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4925 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4926 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4927 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4928 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4929</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4930
4931<p>Note that the code generator does not yet support vector types with
4932 the <tt>icmp</tt> instruction.</p>
4933
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4934</div>
4935
4936<!-- _______________________________________________________________________ -->
4937<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4938</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4939
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4940<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4941
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4942<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4943<pre>
4944 &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]4945</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4946
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4947<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4948<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4949 values based on comparison of its operands.</p>
4950
4951<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]4952(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4953
4954<p>If the operands are floating point vectors, then the result type is a vector
4955 of boolean with the same number of elements as the operands being
4956 compared.</p>
4957
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4958<h5>Arguments:</h5>
4959<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4960 the condition code indicating the kind of comparison to perform. It is not a
4961 value, just a keyword. The possible condition code are:</p>
4962
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4963<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4964 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4965 <li><tt>oeq</tt>: ordered and equal</li>
4966 <li><tt>ogt</tt>: ordered and greater than </li>
4967 <li><tt>oge</tt>: ordered and greater than or equal</li>
4968 <li><tt>olt</tt>: ordered and less than </li>
4969 <li><tt>ole</tt>: ordered and less than or equal</li>
4970 <li><tt>one</tt>: ordered and not equal</li>
4971 <li><tt>ord</tt>: ordered (no nans)</li>
4972 <li><tt>ueq</tt>: unordered or equal</li>
4973 <li><tt>ugt</tt>: unordered or greater than </li>
4974 <li><tt>uge</tt>: unordered or greater than or equal</li>
4975 <li><tt>ult</tt>: unordered or less than </li>
4976 <li><tt>ule</tt>: unordered or less than or equal</li>
4977 <li><tt>une</tt>: unordered or not equal</li>
4978 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4979 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4980</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4981
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4982<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4983 <i>unordered</i> means that either operand may be a QNAN.</p>
4984
4985<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4986 a <a href="#t_floating">floating point</a> type or
4987 a <a href="#t_vector">vector</a> of floating point type. They must have
4988 identical types.</p>
4989
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4990<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4991<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4992 according to the condition code given as <tt>cond</tt>. If the operands are
4993 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4994 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4995 follows:</p>
4996
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4997<ol>
4998 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4999
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5000 <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]5001 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5002
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5003 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5004 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5005
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5006 <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]5007 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5008
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5009 <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]5010 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5011
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5012 <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]5013 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5014
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5015 <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]5016 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5017
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5018 <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]5019
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5020 <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]5021 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5022
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5023 <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]5024 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5025
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5026 <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]5027 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5028
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5029 <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]5030 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5031
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5032 <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]5033 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5034
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5035 <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]5036 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5037
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5038 <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]5039
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5040 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5041</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5042
5043<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5044<pre>
5045 &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]5046 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5047 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5048 &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]5049</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5050
5051<p>Note that the code generator does not yet support vector types with
5052 the <tt>fcmp</tt> instruction.</p>
5053
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5054</div>
5055
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5056<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5057<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5058 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5059</div>
5060
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5061<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5062
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5063<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5064<pre>
5065 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5066</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5067
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5068<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5069<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5070 SSA graph representing the function.</p>
5071
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5072<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5073<p>The type of the incoming values is specified with the first type field. After
5074 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5075 one pair for each predecessor basic block of the current block. Only values
5076 of <a href="#t_firstclass">first class</a> type may be used as the value
5077 arguments to the PHI node. Only labels may be used as the label
5078 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5079
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5080<p>There must be no non-phi instructions between the start of a basic block and
5081 the PHI instructions: i.e. PHI instructions must be first in a basic
5082 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5083
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5084<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5085 occur on the edge from the corresponding predecessor block to the current
5086 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5087 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5088
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5089<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5090<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5091 specified by the pair corresponding to the predecessor basic block that
5092 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5093
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5094<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5095<pre>
5096Loop: ; Infinite loop that counts from 0 on up...
5097 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5098 %nextindvar = add i32 %indvar, 1
5099 br label %Loop
5100</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5101
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5102</div>
5103
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5104<!-- _______________________________________________________________________ -->
5105<div class="doc_subsubsection">
5106 <a name="i_select">'<tt>select</tt>' Instruction</a>
5107</div>
5108
5109<div class="doc_text">
5110
5111<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5112<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5113 &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>
5114
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5115 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5116</pre>
5117
5118<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5119<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5120 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5121
5122
5123<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5124<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5125 values indicating the condition, and two values of the
5126 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5127 vectors and the condition is a scalar, then entire vectors are selected, not
5128 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5129
5130<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5131<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5132 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5133
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5134<p>If the condition is a vector of i1, then the value arguments must be vectors
5135 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5136
5137<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5138<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5139 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5140</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5141
5142<p>Note that the code generator does not yet support conditions
5143 with vector type.</p>
5144
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5145</div>
5146
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5147<!-- _______________________________________________________________________ -->
5148<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5149 <a name="i_call">'<tt>call</tt>' Instruction</a>
5150</div>
5151
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5152<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5153
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5154<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5155<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5156 &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]5157</pre>
5158
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5159<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5160<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5161
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5162<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5163<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5164
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5165<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5166 <li>The optional "tail" marker indicates that the callee function does not
5167 access any allocas or varargs in the caller. Note that calls may be
5168 marked "tail" even if they do not occur before
5169 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5170 present, the function call is eligible for tail call optimization,
5171 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5172 optimized into a jump</a>. The code generator may optimize calls marked
5173 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5174 sibling call optimization</a> when the caller and callee have
5175 matching signatures, or 2) forced tail call optimization when the
5176 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5177 <ul>
5178 <li>Caller and callee both have the calling
5179 convention <tt>fastcc</tt>.</li>
5180 <li>The call is in tail position (ret immediately follows call and ret
5181 uses value of call or is void).</li>
5182 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5183 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5184 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5185 constraints are met.</a></li>
5186 </ul>
5187 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5188
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5189 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5190 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5191 defaults to using C calling conventions. The calling convention of the
5192 call must match the calling convention of the target function, or else the
5193 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5194
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5195 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5196 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5197 '<tt>inreg</tt>' attributes are valid here.</li>
5198
5199 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5200 type of the return value. Functions that return no value are marked
5201 <tt><a href="#t_void">void</a></tt>.</li>
5202
5203 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5204 being invoked. The argument types must match the types implied by this
5205 signature. This type can be omitted if the function is not varargs and if
5206 the function type does not return a pointer to a function.</li>
5207
5208 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5209 be invoked. In most cases, this is a direct function invocation, but
5210 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5211 to function value.</li>
5212
5213 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5214 signature argument types and parameter attributes. All arguments must be
5215 of <a href="#t_firstclass">first class</a> type. If the function
5216 signature indicates the function accepts a variable number of arguments,
5217 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5218
5219 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5220 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5221 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5222</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5223
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5224<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5225<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5226 a specified function, with its incoming arguments bound to the specified
5227 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5228 function, control flow continues with the instruction after the function
5229 call, and the return value of the function is bound to the result
5230 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5231
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5232<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5233<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5234 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5235 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5236 %X = tail call i32 @foo() <i>; yields i32</i>
5237 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5238 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5239
5240 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5241 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5242 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5243 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5244 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5245 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5246</pre>
5247
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5248<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5249standard C99 library as being the C99 library functions, and may perform
5250optimizations or generate code for them under that assumption. This is
5251something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5252freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5253
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5254</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5255
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5256<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5257<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5258 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5259</div>
5260
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5261<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5262
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5263<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5264<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5265 &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]5266</pre>
5267
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5268<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5269<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5270 the "variable argument" area of a function call. It is used to implement the
5271 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5272
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5273<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5274<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5275 argument. It returns a value of the specified argument type and increments
5276 the <tt>va_list</tt> to point to the next argument. The actual type
5277 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5278
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5279<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5280<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5281 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5282 to the next argument. For more information, see the variable argument
5283 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5284
5285<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]5286 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5287 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5288
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5289<p><tt>va_arg</tt> is an LLVM instruction instead of
5290 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5291 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5292
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5293<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5294<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5295
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5296<p>Note that the code generator does not yet fully support va_arg on many
5297 targets. Also, it does not currently support va_arg with aggregate types on
5298 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5299
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5300</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5301
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5302<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5303<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5304<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5305
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5306<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5307
5308<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5309 well known names and semantics and are required to follow certain
5310 restrictions. Overall, these intrinsics represent an extension mechanism for
5311 the LLVM language that does not require changing all of the transformations
5312 in LLVM when adding to the language (or the bitcode reader/writer, the
5313 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5314
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5315<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5316 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5317 begin with this prefix. Intrinsic functions must always be external
5318 functions: you cannot define the body of intrinsic functions. Intrinsic
5319 functions may only be used in call or invoke instructions: it is illegal to
5320 take the address of an intrinsic function. Additionally, because intrinsic
5321 functions are part of the LLVM language, it is required if any are added that
5322 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5323
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5324<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5325 family of functions that perform the same operation but on different data
5326 types. Because LLVM can represent over 8 million different integer types,
5327 overloading is used commonly to allow an intrinsic function to operate on any
5328 integer type. One or more of the argument types or the result type can be
5329 overloaded to accept any integer type. Argument types may also be defined as
5330 exactly matching a previous argument's type or the result type. This allows
5331 an intrinsic function which accepts multiple arguments, but needs all of them
5332 to be of the same type, to only be overloaded with respect to a single
5333 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5334
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5335<p>Overloaded intrinsics will have the names of its overloaded argument types
5336 encoded into its function name, each preceded by a period. Only those types
5337 which are overloaded result in a name suffix. Arguments whose type is matched
5338 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5339 can take an integer of any width and returns an integer of exactly the same
5340 integer width. This leads to a family of functions such as
5341 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5342 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5343 suffix is required. Because the argument's type is matched against the return
5344 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5345
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5346<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5347 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5348
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5349</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5350
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5351<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5352<div class="doc_subsection">
5353 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5354</div>
5355
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5356<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5357
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5358<p>Variable argument support is defined in LLVM with
5359 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5360 intrinsic functions. These functions are related to the similarly named
5361 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5362
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5363<p>All of these functions operate on arguments that use a target-specific value
5364 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5365 not define what this type is, so all transformations should be prepared to
5366 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5367
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5368<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]5369 instruction and the variable argument handling intrinsic functions are
5370 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5371
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5372<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5373<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5374define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5375 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5376 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5377 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5378 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5379
5380 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5381 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5382
5383 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5384 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5385 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5386 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5387 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5388
5389 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5390 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5391 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5392}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5393
5394declare void @llvm.va_start(i8*)
5395declare void @llvm.va_copy(i8*, i8*)
5396declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5397</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5398</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5399
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5400</div>
5401
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5402<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5403<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5404 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5405</div>
5406
5407
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5408<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5409
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5410<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5411<pre>
5412 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5413</pre>
5414
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5415<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5416<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5417 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]5418
5419<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5420<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]5421
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5422<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5423<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]5424 macro available in C. In a target-dependent way, it initializes
5425 the <tt>va_list</tt> element to which the argument points, so that the next
5426 call to <tt>va_arg</tt> will produce the first variable argument passed to
5427 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5428 need to know the last argument of the function as the compiler can figure
5429 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5430
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5431</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5432
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5433<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5434<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5435 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5436</div>
5437
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5438<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5439
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5440<h5>Syntax:</h5>
5441<pre>
5442 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5443</pre>
5444
5445<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5446<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5447 which has been initialized previously
5448 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5449 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5450
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5451<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5452<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]5453
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5454<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5455<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]5456 macro available in C. In a target-dependent way, it destroys
5457 the <tt>va_list</tt> element to which the argument points. Calls
5458 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5459 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5460 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5461
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5462</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5463
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5464<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5465<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5466 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5467</div>
5468
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5469<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5470
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5471<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5472<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5473 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5474</pre>
5475
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5476<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5477<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5478 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5479
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5480<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5481<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]5482 The second argument is a pointer to a <tt>va_list</tt> element to copy
5483 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5484
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5485<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5486<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]5487 macro available in C. In a target-dependent way, it copies the
5488 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5489 element. This intrinsic is necessary because
5490 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5491 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5492
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5493</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5494
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5495<!-- ======================================================================= -->
5496<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5497 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5498</div>
5499
5500<div class="doc_text">
5501
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5502<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5503Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5504intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5505roots on the stack</a>, as well as garbage collector implementations that
5506require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5507barriers. Front-ends for type-safe garbage collected languages should generate
5508these intrinsics to make use of the LLVM garbage collectors. For more details,
5509see <a href="GarbageCollection.html">Accurate Garbage Collection with
5510LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5511
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5512<p>The garbage collection intrinsics only operate on objects in the generic
5513 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5514
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5515</div>
5516
5517<!-- _______________________________________________________________________ -->
5518<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5519 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5520</div>
5521
5522<div class="doc_text">
5523
5524<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5525<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5526 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5527</pre>
5528
5529<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5530<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]5531 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5532
5533<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5534<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5535 root pointer. The second pointer (which must be either a constant or a
5536 global value address) contains the meta-data to be associated with the
5537 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5538
5539<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5540<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]5541 location. At compile-time, the code generator generates information to allow
5542 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5543 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5544 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5545
5546</div>
5547
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5548<!-- _______________________________________________________________________ -->
5549<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5550 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5551</div>
5552
5553<div class="doc_text">
5554
5555<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5556<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5557 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5558</pre>
5559
5560<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5561<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5562 locations, allowing garbage collector implementations that require read
5563 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5564
5565<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5566<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]5567 allocated from the garbage collector. The first object is a pointer to the
5568 start of the referenced object, if needed by the language runtime (otherwise
5569 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5570
5571<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5572<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5573 instruction, but may be replaced with substantially more complex code by the
5574 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5575 may only be used in a function which <a href="#gc">specifies a GC
5576 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5577
5578</div>
5579
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5580<!-- _______________________________________________________________________ -->
5581<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5582 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5583</div>
5584
5585<div class="doc_text">
5586
5587<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5588<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5589 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5590</pre>
5591
5592<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5593<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5594 locations, allowing garbage collector implementations that require write
5595 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5596
5597<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5598<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]5599 object to store it to, and the third is the address of the field of Obj to
5600 store to. If the runtime does not require a pointer to the object, Obj may
5601 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5602
5603<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5604<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5605 instruction, but may be replaced with substantially more complex code by the
5606 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5607 may only be used in a function which <a href="#gc">specifies a GC
5608 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5609
5610</div>
5611
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5612<!-- ======================================================================= -->
5613<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5614 <a name="int_codegen">Code Generator Intrinsics</a>
5615</div>
5616
5617<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5618
5619<p>These intrinsics are provided by LLVM to expose special features that may
5620 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5621
5622</div>
5623
5624<!-- _______________________________________________________________________ -->
5625<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5626 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5627</div>
5628
5629<div class="doc_text">
5630
5631<h5>Syntax:</h5>
5632<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5633 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5634</pre>
5635
5636<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5637<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5638 target-specific value indicating the return address of the current function
5639 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5640
5641<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5642<p>The argument to this intrinsic indicates which function to return the address
5643 for. Zero indicates the calling function, one indicates its caller, etc.
5644 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5645
5646<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5647<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5648 indicating the return address of the specified call frame, or zero if it
5649 cannot be identified. The value returned by this intrinsic is likely to be
5650 incorrect or 0 for arguments other than zero, so it should only be used for
5651 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5652
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5653<p>Note that calling this intrinsic does not prevent function inlining or other
5654 aggressive transformations, so the value returned may not be that of the
5655 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5656
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5657</div>
5658
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5659<!-- _______________________________________________________________________ -->
5660<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5661 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5662</div>
5663
5664<div class="doc_text">
5665
5666<h5>Syntax:</h5>
5667<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5668 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5669</pre>
5670
5671<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5672<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5673 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5674
5675<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5676<p>The argument to this intrinsic indicates which function to return the frame
5677 pointer for. Zero indicates the calling function, one indicates its caller,
5678 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5679
5680<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5681<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5682 indicating the frame address of the specified call frame, or zero if it
5683 cannot be identified. The value returned by this intrinsic is likely to be
5684 incorrect or 0 for arguments other than zero, so it should only be used for
5685 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5686
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5687<p>Note that calling this intrinsic does not prevent function inlining or other
5688 aggressive transformations, so the value returned may not be that of the
5689 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5690
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5691</div>
5692
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5693<!-- _______________________________________________________________________ -->
5694<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5695 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5696</div>
5697
5698<div class="doc_text">
5699
5700<h5>Syntax:</h5>
5701<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5702 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5703</pre>
5704
5705<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5706<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5707 of the function stack, for use
5708 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5709 useful for implementing language features like scoped automatic variable
5710 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5711
5712<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5713<p>This intrinsic returns a opaque pointer value that can be passed
5714 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5715 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5716 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5717 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5718 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5719 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5720
5721</div>
5722
5723<!-- _______________________________________________________________________ -->
5724<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5725 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5726</div>
5727
5728<div class="doc_text">
5729
5730<h5>Syntax:</h5>
5731<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5732 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5733</pre>
5734
5735<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5736<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5737 the function stack to the state it was in when the
5738 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5739 executed. This is useful for implementing language features like scoped
5740 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5741
5742<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5743<p>See the description
5744 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5745
5746</div>
5747
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5748<!-- _______________________________________________________________________ -->
5749<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5750 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5751</div>
5752
5753<div class="doc_text">
5754
5755<h5>Syntax:</h5>
5756<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5757 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]5758</pre>
5759
5760<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5761<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5762 insert a prefetch instruction if supported; otherwise, it is a noop.
5763 Prefetches have no effect on the behavior of the program but can change its
5764 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5765
5766<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5767<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5768 specifier determining if the fetch should be for a read (0) or write (1),
5769 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5770 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5771 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5772
5773<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5774<p>This intrinsic does not modify the behavior of the program. In particular,
5775 prefetches cannot trap and do not produce a value. On targets that support
5776 this intrinsic, the prefetch can provide hints to the processor cache for
5777 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5778
5779</div>
5780
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5781<!-- _______________________________________________________________________ -->
5782<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5783 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5784</div>
5785
5786<div class="doc_text">
5787
5788<h5>Syntax:</h5>
5789<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5790 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5791</pre>
5792
5793<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5794<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5795 Counter (PC) in a region of code to simulators and other tools. The method
5796 is target specific, but it is expected that the marker will use exported
5797 symbols to transmit the PC of the marker. The marker makes no guarantees
5798 that it will remain with any specific instruction after optimizations. It is
5799 possible that the presence of a marker will inhibit optimizations. The
5800 intended use is to be inserted after optimizations to allow correlations of
5801 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5802
5803<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5804<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5805
5806<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5807<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5808 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5809
5810</div>
5811
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5812<!-- _______________________________________________________________________ -->
5813<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5814 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5815</div>
5816
5817<div class="doc_text">
5818
5819<h5>Syntax:</h5>
5820<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5821 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5822</pre>
5823
5824<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5825<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5826 counter register (or similar low latency, high accuracy clocks) on those
5827 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5828 should map to RPCC. As the backing counters overflow quickly (on the order
5829 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5830
5831<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5832<p>When directly supported, reading the cycle counter should not modify any
5833 memory. Implementations are allowed to either return a application specific
5834 value or a system wide value. On backends without support, this is lowered
5835 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5836
5837</div>
5838
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5839<!-- ======================================================================= -->
5840<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5841 <a name="int_libc">Standard C Library Intrinsics</a>
5842</div>
5843
5844<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5845
5846<p>LLVM provides intrinsics for a few important standard C library functions.
5847 These intrinsics allow source-language front-ends to pass information about
5848 the alignment of the pointer arguments to the code generator, providing
5849 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5850
5851</div>
5852
5853<!-- _______________________________________________________________________ -->
5854<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5855 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5856</div>
5857
5858<div class="doc_text">
5859
5860<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5861<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5862 integer bit width. Not all targets support all bit widths however.</p>
5863
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5864<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5865 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5866 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5867 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5868 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5869 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5870 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5871 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5872 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5873</pre>
5874
5875<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5876<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5877 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5878
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5879<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5880 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5881
5882<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5883<p>The first argument is a pointer to the destination, the second is a pointer
5884 to the source. The third argument is an integer argument specifying the
5885 number of bytes to copy, and the fourth argument is the alignment of the
5886 source and destination locations.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5887
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5888<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5889 then the caller guarantees that both the source and destination pointers are
5890 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5891
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5892<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5893<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5894 source location to the destination location, which are not allowed to
5895 overlap. It copies "len" bytes of memory over. If the argument is known to
5896 be aligned to some boundary, this can be specified as the fourth argument,
5897 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5898
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5899</div>
5900
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5901<!-- _______________________________________________________________________ -->
5902<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5903 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5904</div>
5905
5906<div class="doc_text">
5907
5908<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5909<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]5910 width. Not all targets support all bit widths however.</p>
5911
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5912<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5913 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5914 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5915 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5916 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5917 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5918 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5919 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5920 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5921</pre>
5922
5923<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5924<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5925 source location to the destination location. It is similar to the
5926 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5927 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5928
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5929<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5930 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5931
5932<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5933<p>The first argument is a pointer to the destination, the second is a pointer
5934 to the source. The third argument is an integer argument specifying the
5935 number of bytes to copy, and the fourth argument is the alignment of the
5936 source and destination locations.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5937
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5938<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5939 then the caller guarantees that the source and destination pointers are
5940 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5941
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5942<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5943<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5944 source location to the destination location, which may overlap. It copies
5945 "len" bytes of memory over. If the argument is known to be aligned to some
5946 boundary, this can be specified as the fourth argument, otherwise it should
5947 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5948
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5949</div>
5950
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5951<!-- _______________________________________________________________________ -->
5952<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5953 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5954</div>
5955
5956<div class="doc_text">
5957
5958<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5959<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]5960 width. Not all targets support all bit widths however.</p>
5961
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5962<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5963 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5964 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5965 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5966 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5967 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5968 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5969 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5970 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5971</pre>
5972
5973<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5974<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5975 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5976
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5977<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5978 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5979
5980<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5981<p>The first argument is a pointer to the destination to fill, the second is the
5982 byte value to fill it with, the third argument is an integer argument
5983 specifying the number of bytes to fill, and the fourth argument is the known
5984 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5985
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5986<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5987 then the caller guarantees that the destination pointer is aligned to that
5988 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5989
5990<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5991<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5992 at the destination location. If the argument is known to be aligned to some
5993 boundary, this can be specified as the fourth argument, otherwise it should
5994 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5995
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5996</div>
5997
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5998<!-- _______________________________________________________________________ -->
5999<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6000 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6001</div>
6002
6003<div class="doc_text">
6004
6005<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6006<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6007 floating point or vector of floating point type. Not all targets support all
6008 types however.</p>
6009
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6010<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6011 declare float @llvm.sqrt.f32(float %Val)
6012 declare double @llvm.sqrt.f64(double %Val)
6013 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6014 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6015 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6016</pre>
6017
6018<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6019<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6020 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6021 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6022 behavior for negative numbers other than -0.0 (which allows for better
6023 optimization, because there is no need to worry about errno being
6024 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]6025
6026<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6027<p>The argument and return value are floating point numbers of the same
6028 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6029
6030<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6031<p>This function returns the sqrt of the specified operand if it is a
6032 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6033
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6034</div>
6035
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6036<!-- _______________________________________________________________________ -->
6037<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6038 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6039</div>
6040
6041<div class="doc_text">
6042
6043<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6044<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6045 floating point or vector of floating point type. Not all targets support all
6046 types however.</p>
6047
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6048<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6049 declare float @llvm.powi.f32(float %Val, i32 %power)
6050 declare double @llvm.powi.f64(double %Val, i32 %power)
6051 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6052 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6053 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6054</pre>
6055
6056<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6057<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6058 specified (positive or negative) power. The order of evaluation of
6059 multiplications is not defined. When a vector of floating point type is
6060 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6061
6062<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6063<p>The second argument is an integer power, and the first is a value to raise to
6064 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6065
6066<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6067<p>This function returns the first value raised to the second power with an
6068 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6069
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6070</div>
6071
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6072<!-- _______________________________________________________________________ -->
6073<div class="doc_subsubsection">
6074 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6075</div>
6076
6077<div class="doc_text">
6078
6079<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6080<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6081 floating point or vector of floating point type. Not all targets support all
6082 types however.</p>
6083
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6084<pre>
6085 declare float @llvm.sin.f32(float %Val)
6086 declare double @llvm.sin.f64(double %Val)
6087 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6088 declare fp128 @llvm.sin.f128(fp128 %Val)
6089 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6090</pre>
6091
6092<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6093<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6094
6095<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6096<p>The argument and return value are floating point numbers of the same
6097 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6098
6099<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6100<p>This function returns the sine of the specified operand, returning the same
6101 values as the libm <tt>sin</tt> functions would, and handles error conditions
6102 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6103
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6104</div>
6105
6106<!-- _______________________________________________________________________ -->
6107<div class="doc_subsubsection">
6108 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6109</div>
6110
6111<div class="doc_text">
6112
6113<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6114<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6115 floating point or vector of floating point type. Not all targets support all
6116 types however.</p>
6117
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6118<pre>
6119 declare float @llvm.cos.f32(float %Val)
6120 declare double @llvm.cos.f64(double %Val)
6121 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6122 declare fp128 @llvm.cos.f128(fp128 %Val)
6123 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6124</pre>
6125
6126<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6127<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6128
6129<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6130<p>The argument and return value are floating point numbers of the same
6131 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6132
6133<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6134<p>This function returns the cosine of the specified operand, returning the same
6135 values as the libm <tt>cos</tt> functions would, and handles error conditions
6136 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6137
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6138</div>
6139
6140<!-- _______________________________________________________________________ -->
6141<div class="doc_subsubsection">
6142 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6143</div>
6144
6145<div class="doc_text">
6146
6147<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6148<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6149 floating point or vector of floating point type. Not all targets support all
6150 types however.</p>
6151
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6152<pre>
6153 declare float @llvm.pow.f32(float %Val, float %Power)
6154 declare double @llvm.pow.f64(double %Val, double %Power)
6155 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6156 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6157 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6158</pre>
6159
6160<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6161<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6162 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6163
6164<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6165<p>The second argument is a floating point power, and the first is a value to
6166 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6167
6168<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6169<p>This function returns the first value raised to the second power, returning
6170 the same values as the libm <tt>pow</tt> functions would, and handles error
6171 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6172
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6173</div>
6174
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6175<!-- ======================================================================= -->
6176<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6177 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6178</div>
6179
6180<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6181
6182<p>LLVM provides intrinsics for a few important bit manipulation operations.
6183 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6184
6185</div>
6186
6187<!-- _______________________________________________________________________ -->
6188<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6189 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6190</div>
6191
6192<div class="doc_text">
6193
6194<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6195<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6196 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6197
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6198<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6199 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6200 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6201 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6202</pre>
6203
6204<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6205<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6206 values with an even number of bytes (positive multiple of 16 bits). These
6207 are useful for performing operations on data that is not in the target's
6208 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6209
6210<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6211<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6212 and low byte of the input i16 swapped. Similarly,
6213 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6214 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6215 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6216 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6217 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6218 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6219
6220</div>
6221
6222<!-- _______________________________________________________________________ -->
6223<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6224 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6225</div>
6226
6227<div class="doc_text">
6228
6229<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6230<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]6231 width. Not all targets support all bit widths however.</p>
6232
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6233<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6234 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6235 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6236 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6237 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6238 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6239</pre>
6240
6241<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6242<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6243 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6244
6245<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6246<p>The only argument is the value to be counted. The argument may be of any
6247 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6248
6249<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6250<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]6251
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6252</div>
6253
6254<!-- _______________________________________________________________________ -->
6255<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6256 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6257</div>
6258
6259<div class="doc_text">
6260
6261<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6262<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6263 integer bit width. Not all targets support all bit widths however.</p>
6264
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6265<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6266 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6267 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6268 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6269 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6270 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6271</pre>
6272
6273<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6274<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6275 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6276
6277<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6278<p>The only argument is the value to be counted. The argument may be of any
6279 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6280
6281<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6282<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6283 zeros in a variable. If the src == 0 then the result is the size in bits of
6284 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6285
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6286</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6287
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6288<!-- _______________________________________________________________________ -->
6289<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6290 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6291</div>
6292
6293<div class="doc_text">
6294
6295<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6296<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6297 integer bit width. Not all targets support all bit widths however.</p>
6298
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6299<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6300 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6301 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6302 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6303 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6304 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6305</pre>
6306
6307<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6308<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6309 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6310
6311<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6312<p>The only argument is the value to be counted. The argument may be of any
6313 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6314
6315<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6316<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6317 zeros in a variable. If the src == 0 then the result is the size in bits of
6318 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6319
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6320</div>
6321
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6322<!-- ======================================================================= -->
6323<div class="doc_subsection">
6324 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6325</div>
6326
6327<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6328
6329<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6330
6331</div>
6332
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6333<!-- _______________________________________________________________________ -->
6334<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6335 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6336</div>
6337
6338<div class="doc_text">
6339
6340<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6341<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]6342 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6343
6344<pre>
6345 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6346 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6347 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6348</pre>
6349
6350<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6351<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6352 a signed addition of the two arguments, and indicate whether an overflow
6353 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6354
6355<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6356<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]6357 be of integer types of any bit width, but they must have the same bit
6358 width. The second element of the result structure must be of
6359 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6360 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6361
6362<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6363<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6364 a signed addition of the two variables. They return a structure &mdash; the
6365 first element of which is the signed summation, and the second element of
6366 which is a bit specifying if the signed summation resulted in an
6367 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6368
6369<h5>Examples:</h5>
6370<pre>
6371 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6372 %sum = extractvalue {i32, i1} %res, 0
6373 %obit = extractvalue {i32, i1} %res, 1
6374 br i1 %obit, label %overflow, label %normal
6375</pre>
6376
6377</div>
6378
6379<!-- _______________________________________________________________________ -->
6380<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6381 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6382</div>
6383
6384<div class="doc_text">
6385
6386<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6387<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]6388 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6389
6390<pre>
6391 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6392 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6393 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6394</pre>
6395
6396<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6397<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6398 an unsigned addition of the two arguments, and indicate whether a carry
6399 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6400
6401<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6402<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]6403 be of integer types of any bit width, but they must have the same bit
6404 width. The second element of the result structure must be of
6405 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6406 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6407
6408<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6409<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6410 an unsigned addition of the two arguments. They return a structure &mdash;
6411 the first element of which is the sum, and the second element of which is a
6412 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6413
6414<h5>Examples:</h5>
6415<pre>
6416 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6417 %sum = extractvalue {i32, i1} %res, 0
6418 %obit = extractvalue {i32, i1} %res, 1
6419 br i1 %obit, label %carry, label %normal
6420</pre>
6421
6422</div>
6423
6424<!-- _______________________________________________________________________ -->
6425<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6426 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6427</div>
6428
6429<div class="doc_text">
6430
6431<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6432<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]6433 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6434
6435<pre>
6436 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6437 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6438 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6439</pre>
6440
6441<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6442<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6443 a signed subtraction of the two arguments, and indicate whether an overflow
6444 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6445
6446<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6447<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]6448 be of integer types of any bit width, but they must have the same bit
6449 width. The second element of the result structure must be of
6450 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6451 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6452
6453<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6454<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6455 a signed subtraction of the two arguments. They return a structure &mdash;
6456 the first element of which is the subtraction, and the second element of
6457 which is a bit specifying if the signed subtraction resulted in an
6458 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6459
6460<h5>Examples:</h5>
6461<pre>
6462 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6463 %sum = extractvalue {i32, i1} %res, 0
6464 %obit = extractvalue {i32, i1} %res, 1
6465 br i1 %obit, label %overflow, label %normal
6466</pre>
6467
6468</div>
6469
6470<!-- _______________________________________________________________________ -->
6471<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6472 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6473</div>
6474
6475<div class="doc_text">
6476
6477<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6478<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]6479 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6480
6481<pre>
6482 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6483 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6484 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6485</pre>
6486
6487<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6488<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6489 an unsigned subtraction of the two arguments, and indicate whether an
6490 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6491
6492<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6493<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]6494 be of integer types of any bit width, but they must have the same bit
6495 width. The second element of the result structure must be of
6496 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6497 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6498
6499<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6500<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6501 an unsigned subtraction of the two arguments. They return a structure &mdash;
6502 the first element of which is the subtraction, and the second element of
6503 which is a bit specifying if the unsigned subtraction resulted in an
6504 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6505
6506<h5>Examples:</h5>
6507<pre>
6508 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6509 %sum = extractvalue {i32, i1} %res, 0
6510 %obit = extractvalue {i32, i1} %res, 1
6511 br i1 %obit, label %overflow, label %normal
6512</pre>
6513
6514</div>
6515
6516<!-- _______________________________________________________________________ -->
6517<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6518 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6519</div>
6520
6521<div class="doc_text">
6522
6523<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6524<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]6525 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6526
6527<pre>
6528 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6529 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6530 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6531</pre>
6532
6533<h5>Overview:</h5>
6534
6535<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6536 a signed multiplication of the two arguments, and indicate whether an
6537 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6538
6539<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6540<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]6541 be of integer types of any bit width, but they must have the same bit
6542 width. The second element of the result structure must be of
6543 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6544 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6545
6546<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6547<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6548 a signed multiplication of the two arguments. They return a structure &mdash;
6549 the first element of which is the multiplication, and the second element of
6550 which is a bit specifying if the signed multiplication resulted in an
6551 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6552
6553<h5>Examples:</h5>
6554<pre>
6555 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6556 %sum = extractvalue {i32, i1} %res, 0
6557 %obit = extractvalue {i32, i1} %res, 1
6558 br i1 %obit, label %overflow, label %normal
6559</pre>
6560
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6561</div>
6562
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6563<!-- _______________________________________________________________________ -->
6564<div class="doc_subsubsection">
6565 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6566</div>
6567
6568<div class="doc_text">
6569
6570<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6571<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]6572 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6573
6574<pre>
6575 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6576 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6577 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6578</pre>
6579
6580<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6581<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6582 a unsigned multiplication of the two arguments, and indicate whether an
6583 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6584
6585<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6586<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]6587 be of integer types of any bit width, but they must have the same bit
6588 width. The second element of the result structure must be of
6589 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6590 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6591
6592<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6593<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6594 an unsigned multiplication of the two arguments. They return a structure
6595 &mdash; the first element of which is the multiplication, and the second
6596 element of which is a bit specifying if the unsigned multiplication resulted
6597 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6598
6599<h5>Examples:</h5>
6600<pre>
6601 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6602 %sum = extractvalue {i32, i1} %res, 0
6603 %obit = extractvalue {i32, i1} %res, 1
6604 br i1 %obit, label %overflow, label %normal
6605</pre>
6606
6607</div>
6608
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6609<!-- ======================================================================= -->
6610<div class="doc_subsection">
6611 <a name="int_debugger">Debugger Intrinsics</a>
6612</div>
6613
6614<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6615
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6616<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6617 prefix), are described in
6618 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6619 Level Debugging</a> document.</p>
6620
6621</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6622
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6623<!-- ======================================================================= -->
6624<div class="doc_subsection">
6625 <a name="int_eh">Exception Handling Intrinsics</a>
6626</div>
6627
6628<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6629
6630<p>The LLVM exception handling intrinsics (which all start with
6631 <tt>llvm.eh.</tt> prefix), are described in
6632 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6633 Handling</a> document.</p>
6634
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6635</div>
6636
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6637<!-- ======================================================================= -->
6638<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6639 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6640</div>
6641
6642<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6643
6644<p>This intrinsic makes it possible to excise one parameter, marked with
6645 the <tt>nest</tt> attribute, from a function. The result is a callable
6646 function pointer lacking the nest parameter - the caller does not need to
6647 provide a value for it. Instead, the value to use is stored in advance in a
6648 "trampoline", a block of memory usually allocated on the stack, which also
6649 contains code to splice the nest value into the argument list. This is used
6650 to implement the GCC nested function address extension.</p>
6651
6652<p>For example, if the function is
6653 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6654 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6655 follows:</p>
6656
6657<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6658<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6659 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6660 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6661 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6662 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6663</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6664</div>
6665
6666<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6667 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6668
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6669</div>
6670
6671<!-- _______________________________________________________________________ -->
6672<div class="doc_subsubsection">
6673 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6674</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6675
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6676<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6677
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6678<h5>Syntax:</h5>
6679<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6680 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]6681</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6682
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6683<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6684<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6685 function pointer suitable for executing it.</p>
6686
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6687<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6688<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6689 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6690 sufficiently aligned block of memory; this memory is written to by the
6691 intrinsic. Note that the size and the alignment are target-specific - LLVM
6692 currently provides no portable way of determining them, so a front-end that
6693 generates this intrinsic needs to have some target-specific knowledge.
6694 The <tt>func</tt> argument must hold a function bitcast to
6695 an <tt>i8*</tt>.</p>
6696
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6697<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6698<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6699 dependent code, turning it into a function. A pointer to this function is
6700 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6701 function pointer type</a> before being called. The new function's signature
6702 is the same as that of <tt>func</tt> with any arguments marked with
6703 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6704 is allowed, and it must be of pointer type. Calling the new function is
6705 equivalent to calling <tt>func</tt> with the same argument list, but
6706 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6707 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6708 by <tt>tramp</tt> is modified, then the effect of any later call to the
6709 returned function pointer is undefined.</p>
6710
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6711</div>
6712
6713<!-- ======================================================================= -->
6714<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6715 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6716</div>
6717
6718<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6719
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6720<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6721 hardware constructs for atomic operations and memory synchronization. This
6722 provides an interface to the hardware, not an interface to the programmer. It
6723 is aimed at a low enough level to allow any programming models or APIs
6724 (Application Programming Interfaces) which need atomic behaviors to map
6725 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6726 hardware provides a "universal IR" for source languages, it also provides a
6727 starting point for developing a "universal" atomic operation and
6728 synchronization IR.</p>
6729
6730<p>These do <em>not</em> form an API such as high-level threading libraries,
6731 software transaction memory systems, atomic primitives, and intrinsic
6732 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6733 application libraries. The hardware interface provided by LLVM should allow
6734 a clean implementation of all of these APIs and parallel programming models.
6735 No one model or paradigm should be selected above others unless the hardware
6736 itself ubiquitously does so.</p>
6737
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6738</div>
6739
6740<!-- _______________________________________________________________________ -->
6741<div class="doc_subsubsection">
6742 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6743</div>
6744<div class="doc_text">
6745<h5>Syntax:</h5>
6746<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6747 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]6748</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6749
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6750<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6751<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6752 specific pairs of memory access types.</p>
6753
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6754<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6755<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6756 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6757 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6758 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6759
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6760<ul>
6761 <li><tt>ll</tt>: load-load barrier</li>
6762 <li><tt>ls</tt>: load-store barrier</li>
6763 <li><tt>sl</tt>: store-load barrier</li>
6764 <li><tt>ss</tt>: store-store barrier</li>
6765 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6766</ul>
6767
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6768<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6769<p>This intrinsic causes the system to enforce some ordering constraints upon
6770 the loads and stores of the program. This barrier does not
6771 indicate <em>when</em> any events will occur, it only enforces
6772 an <em>order</em> in which they occur. For any of the specified pairs of load
6773 and store operations (f.ex. load-load, or store-load), all of the first
6774 operations preceding the barrier will complete before any of the second
6775 operations succeeding the barrier begin. Specifically the semantics for each
6776 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6777
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6778<ul>
6779 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6780 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6781 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6782 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6783 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6784 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6785 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6786 load after the barrier begins.</li>
6787</ul>
6788
6789<p>These semantics are applied with a logical "and" behavior when more than one
6790 is enabled in a single memory barrier intrinsic.</p>
6791
6792<p>Backends may implement stronger barriers than those requested when they do
6793 not support as fine grained a barrier as requested. Some architectures do
6794 not need all types of barriers and on such architectures, these become
6795 noops.</p>
6796
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6797<h5>Example:</h5>
6798<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6799%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6800%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6801 store i32 4, %ptr
6802
6803%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6804 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6805 <i>; guarantee the above finishes</i>
6806 store i32 8, %ptr <i>; before this begins</i>
6807</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6808
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6809</div>
6810
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6811<!-- _______________________________________________________________________ -->
6812<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6813 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6814</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6815
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6816<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6817
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6818<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6819<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6820 any integer bit width and for different address spaces. Not all targets
6821 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6822
6823<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6824 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6825 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6826 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6827 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]6828</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6829
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6830<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6831<p>This loads a value in memory and compares it to a given value. If they are
6832 equal, it stores a new value into the memory.</p>
6833
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6834<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6835<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6836 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6837 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6838 this integer type. While any bit width integer may be used, targets may only
6839 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6840
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6841<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6842<p>This entire intrinsic must be executed atomically. It first loads the value
6843 in memory pointed to by <tt>ptr</tt> and compares it with the
6844 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6845 memory. The loaded value is yielded in all cases. This provides the
6846 equivalent of an atomic compare-and-swap operation within the SSA
6847 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6848
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6849<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6850<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6851%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6852%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6853 store i32 4, %ptr
6854
6855%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6856%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6857 <i>; yields {i32}:result1 = 4</i>
6858%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6859%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6860
6861%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6862%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6863 <i>; yields {i32}:result2 = 8</i>
6864%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6865
6866%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6867</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6868
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6869</div>
6870
6871<!-- _______________________________________________________________________ -->
6872<div class="doc_subsubsection">
6873 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6874</div>
6875<div class="doc_text">
6876<h5>Syntax:</h5>
6877
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6878<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6879 integer bit width. Not all targets support all bit widths however.</p>
6880
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6881<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6882 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6883 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6884 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6885 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]6886</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6887
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6888<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6889<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6890 the value from memory. It then stores the value in <tt>val</tt> in the memory
6891 at <tt>ptr</tt>.</p>
6892
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6893<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6894<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6895 the <tt>val</tt> argument and the result must be integers of the same bit
6896 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6897 integer type. The targets may only lower integer representations they
6898 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6899
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6900<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6901<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6902 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6903 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6904
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6905<h5>Examples:</h5>
6906<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6907%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6908%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6909 store i32 4, %ptr
6910
6911%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6912%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6913 <i>; yields {i32}:result1 = 4</i>
6914%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6915%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6916
6917%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6918%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6919 <i>; yields {i32}:result2 = 8</i>
6920
6921%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6922%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6923</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6924
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6925</div>
6926
6927<!-- _______________________________________________________________________ -->
6928<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6929 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6930
6931</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6932
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6933<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6934
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6935<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6936<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6937 any integer bit width. Not all targets support all bit widths however.</p>
6938
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6939<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6940 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6941 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6942 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6943 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]6944</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6945
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6946<h5>Overview:</h5>
6947<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6948 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6949
6950<h5>Arguments:</h5>
6951<p>The intrinsic takes two arguments, the first a pointer to an integer value
6952 and the second an integer value. The result is also an integer value. These
6953 integer types can have any bit width, but they must all have the same bit
6954 width. The targets may only lower integer representations they support.</p>
6955
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6956<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6957<p>This intrinsic does a series of operations atomically. It first loads the
6958 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6959 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]6960
6961<h5>Examples:</h5>
6962<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6963%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6964%ptr = bitcast i8* %mallocP to i32*
6965 store i32 4, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6966%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6967 <i>; yields {i32}:result1 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6968%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6969 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6970%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6971 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6972%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6973</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6974
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6975</div>
6976
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6977<!-- _______________________________________________________________________ -->
6978<div class="doc_subsubsection">
6979 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6980
6981</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6982
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6983<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6984
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6985<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6986<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6987 any integer bit width and for different address spaces. Not all targets
6988 support all bit widths however.</p>
6989
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6990<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6991 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6992 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6993 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6994 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]6995</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6996
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6997<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6998<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6999 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7000
7001<h5>Arguments:</h5>
7002<p>The intrinsic takes two arguments, the first a pointer to an integer value
7003 and the second an integer value. The result is also an integer value. These
7004 integer types can have any bit width, but they must all have the same bit
7005 width. The targets may only lower integer representations they support.</p>
7006
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7007<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7008<p>This intrinsic does a series of operations atomically. It first loads the
7009 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7010 result to <tt>ptr</tt>. It yields the original value stored
7011 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7012
7013<h5>Examples:</h5>
7014<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7015%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7016%ptr = bitcast i8* %mallocP to i32*
7017 store i32 8, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7018%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7019 <i>; yields {i32}:result1 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7020%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7021 <i>; yields {i32}:result2 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7022%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7023 <i>; yields {i32}:result3 = 2</i>
7024%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7025</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7026
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7027</div>
7028
7029<!-- _______________________________________________________________________ -->
7030<div class="doc_subsubsection">
7031 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7032 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7033 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7034 <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]7035</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7036
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7037<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7038
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7039<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7040<p>These are overloaded intrinsics. You can
7041 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7042 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7043 bit width and for different address spaces. Not all targets support all bit
7044 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7045
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7046<pre>
7047 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7048 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7049 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7050 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]7051</pre>
7052
7053<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7054 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7055 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7056 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7057 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]7058</pre>
7059
7060<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7061 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7062 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7063 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7064 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]7065</pre>
7066
7067<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7068 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7069 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7070 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7071 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]7072</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7073
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7074<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7075<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7076 the value stored in memory at <tt>ptr</tt>. It yields the original value
7077 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7078
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7079<h5>Arguments:</h5>
7080<p>These intrinsics take two arguments, the first a pointer to an integer value
7081 and the second an integer value. The result is also an integer value. These
7082 integer types can have any bit width, but they must all have the same bit
7083 width. The targets may only lower integer representations they support.</p>
7084
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7085<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7086<p>These intrinsics does a series of operations atomically. They first load the
7087 value stored at <tt>ptr</tt>. They then do the bitwise
7088 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7089 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7090
7091<h5>Examples:</h5>
7092<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7093%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7094%ptr = bitcast i8* %mallocP to i32*
7095 store i32 0x0F0F, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7096%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7097 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7098%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7099 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7100%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7101 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7102%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7103 <i>; yields {i32}:result3 = FF</i>
7104%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7105</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7106
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7107</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7108
7109<!-- _______________________________________________________________________ -->
7110<div class="doc_subsubsection">
7111 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7112 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7113 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7114 <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]7115</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7116
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7117<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7118
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7119<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7120<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7121 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7122 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7123 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7124
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7125<pre>
7126 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7127 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7128 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7129 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]7130</pre>
7131
7132<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7133 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7134 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7135 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7136 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]7137</pre>
7138
7139<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7140 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7141 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7142 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7143 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]7144</pre>
7145
7146<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7147 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7148 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7149 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7150 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]7151</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7152
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7153<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7154<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7155 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7156 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7157
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7158<h5>Arguments:</h5>
7159<p>These intrinsics take two arguments, the first a pointer to an integer value
7160 and the second an integer value. The result is also an integer value. These
7161 integer types can have any bit width, but they must all have the same bit
7162 width. The targets may only lower integer representations they support.</p>
7163
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7164<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7165<p>These intrinsics does a series of operations atomically. They first load the
7166 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7167 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7168 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7169
7170<h5>Examples:</h5>
7171<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7172%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7173%ptr = bitcast i8* %mallocP to i32*
7174 store i32 7, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7175%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7176 <i>; yields {i32}:result0 = 7</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7177%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7178 <i>; yields {i32}:result1 = -2</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7179%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7180 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7181%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7182 <i>; yields {i32}:result3 = 8</i>
7183%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7184</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7185
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7186</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7187
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7188
7189<!-- ======================================================================= -->
7190<div class="doc_subsection">
7191 <a name="int_memorymarkers">Memory Use Markers</a>
7192</div>
7193
7194<div class="doc_text">
7195
7196<p>This class of intrinsics exists to information about the lifetime of memory
7197 objects and ranges where variables are immutable.</p>
7198
7199</div>
7200
7201<!-- _______________________________________________________________________ -->
7202<div class="doc_subsubsection">
7203 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7204</div>
7205
7206<div class="doc_text">
7207
7208<h5>Syntax:</h5>
7209<pre>
7210 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7211</pre>
7212
7213<h5>Overview:</h5>
7214<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7215 object's lifetime.</p>
7216
7217<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7218<p>The first argument is a constant integer representing the size of the
7219 object, or -1 if it is variable sized. The second argument is a pointer to
7220 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7221
7222<h5>Semantics:</h5>
7223<p>This intrinsic indicates that before this point in the code, the value of the
7224 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]7225 never be used and has an undefined value. A load from the pointer that
7226 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7227 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7228
7229</div>
7230
7231<!-- _______________________________________________________________________ -->
7232<div class="doc_subsubsection">
7233 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7234</div>
7235
7236<div class="doc_text">
7237
7238<h5>Syntax:</h5>
7239<pre>
7240 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7241</pre>
7242
7243<h5>Overview:</h5>
7244<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7245 object's lifetime.</p>
7246
7247<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7248<p>The first argument is a constant integer representing the size of the
7249 object, or -1 if it is variable sized. The second argument is a pointer to
7250 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7251
7252<h5>Semantics:</h5>
7253<p>This intrinsic indicates that after this point in the code, the value of the
7254 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7255 never be used and has an undefined value. Any stores into the memory object
7256 following this intrinsic may be removed as dead.
7257
7258</div>
7259
7260<!-- _______________________________________________________________________ -->
7261<div class="doc_subsubsection">
7262 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7263</div>
7264
7265<div class="doc_text">
7266
7267<h5>Syntax:</h5>
7268<pre>
7269 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7270</pre>
7271
7272<h5>Overview:</h5>
7273<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7274 a memory object will not change.</p>
7275
7276<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7277<p>The first argument is a constant integer representing the size of the
7278 object, or -1 if it is variable sized. The second argument is a pointer to
7279 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7280
7281<h5>Semantics:</h5>
7282<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7283 the return value, the referenced memory location is constant and
7284 unchanging.</p>
7285
7286</div>
7287
7288<!-- _______________________________________________________________________ -->
7289<div class="doc_subsubsection">
7290 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7291</div>
7292
7293<div class="doc_text">
7294
7295<h5>Syntax:</h5>
7296<pre>
7297 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7298</pre>
7299
7300<h5>Overview:</h5>
7301<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7302 a memory object are mutable.</p>
7303
7304<h5>Arguments:</h5>
7305<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7306 The second argument is a constant integer representing the size of the
7307 object, or -1 if it is variable sized and the third argument is a pointer
7308 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7309
7310<h5>Semantics:</h5>
7311<p>This intrinsic indicates that the memory is mutable again.</p>
7312
7313</div>
7314
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7315<!-- ======================================================================= -->
7316<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7317 <a name="int_general">General Intrinsics</a>
7318</div>
7319
7320<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7321
7322<p>This class of intrinsics is designed to be generic and has no specific
7323 purpose.</p>
7324
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7325</div>
7326
7327<!-- _______________________________________________________________________ -->
7328<div class="doc_subsubsection">
7329 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7330</div>
7331
7332<div class="doc_text">
7333
7334<h5>Syntax:</h5>
7335<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]7336 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]7337</pre>
7338
7339<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7340<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7341
7342<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7343<p>The first argument is a pointer to a value, the second is a pointer to a
7344 global string, the third is a pointer to a global string which is the source
7345 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7346
7347<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7348<p>This intrinsic allows annotation of local variables with arbitrary strings.
7349 This can be useful for special purpose optimizations that want to look for
7350 these annotations. These have no other defined use, they are ignored by code
7351 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7352
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7353</div>
7354
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7355<!-- _______________________________________________________________________ -->
7356<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7357 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7358</div>
7359
7360<div class="doc_text">
7361
7362<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7363<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7364 any integer bit width.</p>
7365
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7366<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]7367 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7368 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7369 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7370 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7371 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]7372</pre>
7373
7374<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7375<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7376
7377<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7378<p>The first argument is an integer value (result of some expression), the
7379 second is a pointer to a global string, the third is a pointer to a global
7380 string which is the source file name, and the last argument is the line
7381 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7382
7383<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7384<p>This intrinsic allows annotations to be put on arbitrary expressions with
7385 arbitrary strings. This can be useful for special purpose optimizations that
7386 want to look for these annotations. These have no other defined use, they
7387 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7388
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7389</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7390
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7391<!-- _______________________________________________________________________ -->
7392<div class="doc_subsubsection">
7393 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7394</div>
7395
7396<div class="doc_text">
7397
7398<h5>Syntax:</h5>
7399<pre>
7400 declare void @llvm.trap()
7401</pre>
7402
7403<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7404<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7405
7406<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7407<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7408
7409<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7410<p>This intrinsics is lowered to the target dependent trap instruction. If the
7411 target does not have a trap instruction, this intrinsic will be lowered to
7412 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7413
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7414</div>
7415
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7416<!-- _______________________________________________________________________ -->
7417<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7418 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7419</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7420
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7421<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7422
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7423<h5>Syntax:</h5>
7424<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7425 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7426</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7427
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7428<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7429<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7430 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7431 ensure that it is placed on the stack before local variables.</p>
7432
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7433<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7434<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7435 arguments. The first argument is the value loaded from the stack
7436 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7437 that has enough space to hold the value of the guard.</p>
7438
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7439<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7440<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7441 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7442 stack. This is to ensure that if a local variable on the stack is
7443 overwritten, it will destroy the value of the guard. When the function exits,
7444 the guard on the stack is checked against the original guard. If they're
7445 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7446 function.</p>
7447
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7448</div>
7449
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7450<!-- _______________________________________________________________________ -->
7451<div class="doc_subsubsection">
7452 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7453</div>
7454
7455<div class="doc_text">
7456
7457<h5>Syntax:</h5>
7458<pre>
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7459 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7460 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7461</pre>
7462
7463<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7464<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7465 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7466 operation like memcpy will either overflow a buffer that corresponds to
7467 an object, or b) to determine that a runtime check for overflow isn't
7468 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7469 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7470
7471<h5>Arguments:</h5>
7472<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7473 argument is a pointer to or into the <tt>object</tt>. The second argument
7474 is a boolean 0 or 1. This argument determines whether you want the
7475 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7476 1, variables are not allowed.</p>
7477
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7478<h5>Semantics:</h5>
7479<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7480 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7481 (depending on the <tt>type</tt> argument if the size cannot be determined
7482 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7483
7484</div>
7485
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7486<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7487<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7488<address>
7489 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7490 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7491 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7493
7494 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7495 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7496 Last modified: $Date$
7497</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7498
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7499</body>
7500</html>