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gerrit-public.fairphone.software / toolchain / llvm-project / 8ad777dc75acd5ae18f280a1077c45c33ea0ed3d / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]46 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]47 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]48 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]49 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]50 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]51 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]52 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]53 </ol>
54 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]55 <li><a href="#typesystem">Type System</a>
56 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]57 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]58 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]59 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]60 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]61 <li><a href="#t_floating">Floating Point Types</a></li>
62 <li><a href="#t_void">Void Type</a></li>
63 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]64 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]65 </ol>
66 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]67 <li><a href="#t_derived">Derived Types</a>
68 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]69 <li><a href="#t_aggregate">Aggregate Types</a>
70 <ol>
71 <li><a href="#t_array">Array Type</a></li>
72 <li><a href="#t_struct">Structure Type</a></li>
73 <li><a href="#t_pstruct">Packed Structure Type</a></li>
74 <li><a href="#t_union">Union Type</a></li>
75 <li><a href="#t_vector">Vector Type</a></li>
76 </ol>
77 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]78 <li><a href="#t_function">Function Type</a></li>
79 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]80 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]81 </ol>
82 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]83 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]84 </ol>
85 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]86 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]87 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]88 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]89 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]90 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
91 <li><a href="#undefvalues">Undefined Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]92 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]94 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]95 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]96 <li><a href="#othervalues">Other Values</a>
97 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]98 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]99 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]102 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
103 <ol>
104 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]105 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
106 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]107 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
108 Global Variable</a></li>
109 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
110 Global Variable</a></li>
111 </ol>
112 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]113 <li><a href="#instref">Instruction Reference</a>
114 <ol>
115 <li><a href="#terminators">Terminator Instructions</a>
116 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]117 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
118 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]119 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]120 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]121 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]123 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]124 </ol>
125 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]126 <li><a href="#binaryops">Binary Operations</a>
127 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]128 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]129 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]130 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]131 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]134 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
135 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
136 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]137 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
138 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
139 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]140 </ol>
141 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]142 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
143 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]144 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
145 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
146 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]147 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]149 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]150 </ol>
151 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]152 <li><a href="#vectorops">Vector Operations</a>
153 <ol>
154 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
155 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
156 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]157 </ol>
158 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]159 <li><a href="#aggregateops">Aggregate Operations</a>
160 <ol>
161 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
162 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
163 </ol>
164 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]165 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]166 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]167 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]168 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
169 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
170 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]171 </ol>
172 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]173 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]174 <ol>
175 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
176 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
177 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
178 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
179 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]180 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
182 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
183 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]184 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
185 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]186 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]187 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]188 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]189 <li><a href="#otherops">Other Operations</a>
190 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]191 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
192 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]193 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]194 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]195 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]196 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]197 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]198 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]199 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]200 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]201 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]202 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]203 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
204 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]205 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
206 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
207 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]208 </ol>
209 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]210 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
211 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]212 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
213 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
214 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]215 </ol>
216 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]217 <li><a href="#int_codegen">Code Generator Intrinsics</a>
218 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]219 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
220 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
221 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
222 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
223 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
224 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
225 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]226 </ol>
227 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]228 <li><a href="#int_libc">Standard C Library Intrinsics</a>
229 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]230 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
232 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
233 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]235 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]238 </ol>
239 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]240 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]241 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]242 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]243 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
244 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
245 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]246 </ol>
247 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]248 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
249 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]250 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
251 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
252 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
253 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]255 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]256 </ol>
257 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]258 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]259 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]260 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]261 <ol>
262 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]263 </ol>
264 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]265 <li><a href="#int_atomics">Atomic intrinsics</a>
266 <ol>
267 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
268 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
269 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
270 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
271 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
272 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
273 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
274 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
275 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
276 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
277 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
278 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
279 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
280 </ol>
281 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]282 <li><a href="#int_memorymarkers">Memory Use Markers</a>
283 <ol>
284 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
285 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
286 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
287 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
288 </ol>
289 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]290 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]291 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]292 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]293 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]294 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]295 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]296 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]297 '<tt>llvm.trap</tt>' Intrinsic</a></li>
298 <li><a href="#int_stackprotector">
299 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]300 <li><a href="#int_objectsize">
301 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]302 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]303 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]304 </ol>
305 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]306</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]307
308<div class="doc_author">
309 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
310 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]311</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]312
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]313<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]314<div class="doc_section"> <a name="abstract">Abstract </a></div>
315<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]316
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]317<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]318
319<p>This document is a reference manual for the LLVM assembly language. LLVM is
320 a Static Single Assignment (SSA) based representation that provides type
321 safety, low-level operations, flexibility, and the capability of representing
322 'all' high-level languages cleanly. It is the common code representation
323 used throughout all phases of the LLVM compilation strategy.</p>
324
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]325</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]326
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]327<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]328<div class="doc_section"> <a name="introduction">Introduction</a> </div>
329<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]330
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]331<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]332
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]333<p>The LLVM code representation is designed to be used in three different forms:
334 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
335 for fast loading by a Just-In-Time compiler), and as a human readable
336 assembly language representation. This allows LLVM to provide a powerful
337 intermediate representation for efficient compiler transformations and
338 analysis, while providing a natural means to debug and visualize the
339 transformations. The three different forms of LLVM are all equivalent. This
340 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]341
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM representation aims to be light-weight and low-level while being
343 expressive, typed, and extensible at the same time. It aims to be a
344 "universal IR" of sorts, by being at a low enough level that high-level ideas
345 may be cleanly mapped to it (similar to how microprocessors are "universal
346 IR's", allowing many source languages to be mapped to them). By providing
347 type information, LLVM can be used as the target of optimizations: for
348 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]349 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]350 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]351
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]352</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]353
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]354<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]355<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]356
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]357<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]358
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]359<p>It is important to note that this document describes 'well formed' LLVM
360 assembly language. There is a difference between what the parser accepts and
361 what is considered 'well formed'. For example, the following instruction is
362 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]363
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]364<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]365<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]366%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]367</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]368</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]369
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]370<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
371 LLVM infrastructure provides a verification pass that may be used to verify
372 that an LLVM module is well formed. This pass is automatically run by the
373 parser after parsing input assembly and by the optimizer before it outputs
374 bitcode. The violations pointed out by the verifier pass indicate bugs in
375 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]376
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]377</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]378
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]379<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]380
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]381<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]382<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]383<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]384
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]385<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]386
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]387<p>LLVM identifiers come in two basic types: global and local. Global
388 identifiers (functions, global variables) begin with the <tt>'@'</tt>
389 character. Local identifiers (register names, types) begin with
390 the <tt>'%'</tt> character. Additionally, there are three different formats
391 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]392
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]393<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]394 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]395 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
396 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
397 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
398 other characters in their names can be surrounded with quotes. Special
399 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
400 ASCII code for the character in hexadecimal. In this way, any character
401 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]402
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]403 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]404 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]405
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]406 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]407 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]408</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]409
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]410<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]411 don't need to worry about name clashes with reserved words, and the set of
412 reserved words may be expanded in the future without penalty. Additionally,
413 unnamed identifiers allow a compiler to quickly come up with a temporary
414 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]415
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]416<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]417 languages. There are keywords for different opcodes
418 ('<tt><a href="#i_add">add</a></tt>',
419 '<tt><a href="#i_bitcast">bitcast</a></tt>',
420 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
421 ('<tt><a href="#t_void">void</a></tt>',
422 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
423 reserved words cannot conflict with variable names, because none of them
424 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]425
426<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]427 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]428
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]429<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]430
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]431<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]432<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]433%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]434</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]435</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]437<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]438
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]439<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]440<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]441%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]442</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]443</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]444
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]445<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]446
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]447<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448<pre>
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]449%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
450%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]451%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]452</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]453</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]455<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
456 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]457
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]458<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]459 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]460 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]461
462 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]463 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]464
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]465 <li>Unnamed temporaries are numbered sequentially</li>
466</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]467
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]468<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]469 demonstrating instructions, we will follow an instruction with a comment that
470 defines the type and name of value produced. Comments are shown in italic
471 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]472
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]473</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]474
475<!-- *********************************************************************** -->
476<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
477<!-- *********************************************************************** -->
478
479<!-- ======================================================================= -->
480<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
481</div>
482
483<div class="doc_text">
484
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]485<p>LLVM programs are composed of "Module"s, each of which is a translation unit
486 of the input programs. Each module consists of functions, global variables,
487 and symbol table entries. Modules may be combined together with the LLVM
488 linker, which merges function (and global variable) definitions, resolves
489 forward declarations, and merges symbol table entries. Here is an example of
490 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]491
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]492<div class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]493<pre>
494<i>; Declare the string constant as a global constant.</i>
495<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]496
497<i>; External declaration of the puts function</i>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]498<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]499
500<i>; Definition of main function</i>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]501define i32 @main() { <i>; i32()* </i>
502 <i>; Convert [13 x i8]* to i8 *...</i>
503 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]504
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]505 <i>; Call puts function to write out the string to stdout.</i>
506 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]507 <a href="#i_ret">ret</a> i32 0<br>}
508
509<i>; Named metadata</i>
510!1 = metadata !{i32 41}
511!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]512</pre>
513</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]514
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]515<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]516 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]517 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]518 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
519 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]520
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]521<p>In general, a module is made up of a list of global values, where both
522 functions and global variables are global values. Global values are
523 represented by a pointer to a memory location (in this case, a pointer to an
524 array of char, and a pointer to a function), and have one of the
525 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]526
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]527</div>
528
529<!-- ======================================================================= -->
530<div class="doc_subsection">
531 <a name="linkage">Linkage Types</a>
532</div>
533
534<div class="doc_text">
535
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]536<p>All Global Variables and Functions have one of the following types of
537 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]538
539<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]540 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]541 <dd>Global values with private linkage are only directly accessible by objects
542 in the current module. In particular, linking code into a module with an
543 private global value may cause the private to be renamed as necessary to
544 avoid collisions. Because the symbol is private to the module, all
545 references can be updated. This doesn't show up in any symbol table in the
546 object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]547
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]549 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere7f064e2009-08-24 04:32:16 +0000[diff] [blame]550 removed by the linker after evaluation. Note that (unlike private
551 symbols) linker_private symbols are subject to coalescing by the linker:
552 weak symbols get merged and redefinitions are rejected. However, unlike
553 normal strong symbols, they are removed by the linker from the final
554 linked image (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]555
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]557 <dd>Similar to private, but the value shows as a local symbol
558 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
559 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]560
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]562 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]563 into the object file corresponding to the LLVM module. They exist to
564 allow inlining and other optimizations to take place given knowledge of
565 the definition of the global, which is known to be somewhere outside the
566 module. Globals with <tt>available_externally</tt> linkage are allowed to
567 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
568 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]569
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]571 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]572 the same name when linkage occurs. This can be used to implement
573 some forms of inline functions, templates, or other code which must be
574 generated in each translation unit that uses it, but where the body may
575 be overridden with a more definitive definition later. Unreferenced
576 <tt>linkonce</tt> globals are allowed to be discarded. Note that
577 <tt>linkonce</tt> linkage does not actually allow the optimizer to
578 inline the body of this function into callers because it doesn't know if
579 this definition of the function is the definitive definition within the
580 program or whether it will be overridden by a stronger definition.
581 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
582 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]583
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]585 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
586 <tt>linkonce</tt> linkage, except that unreferenced globals with
587 <tt>weak</tt> linkage may not be discarded. This is used for globals that
588 are declared "weak" in C source code.</dd>
589
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]591 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
592 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
593 global scope.
594 Symbols with "<tt>common</tt>" linkage are merged in the same way as
595 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]596 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]597 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]598 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
599 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]600
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]601
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]602 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]603 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]604 pointer to array type. When two global variables with appending linkage
605 are linked together, the two global arrays are appended together. This is
606 the LLVM, typesafe, equivalent of having the system linker append together
607 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]608
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]609 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]610 <dd>The semantics of this linkage follow the ELF object file model: the symbol
611 is weak until linked, if not linked, the symbol becomes null instead of
612 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]613
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]614 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
615 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]616 <dd>Some languages allow differing globals to be merged, such as two functions
617 with different semantics. Other languages, such as <tt>C++</tt>, ensure
618 that only equivalent globals are ever merged (the "one definition rule" -
619 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
620 and <tt>weak_odr</tt> linkage types to indicate that the global will only
621 be merged with equivalent globals. These linkage types are otherwise the
622 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]623
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]624 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]625 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]626 visible, meaning that it participates in linkage and can be used to
627 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]628</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]629
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]630<p>The next two types of linkage are targeted for Microsoft Windows platform
631 only. They are designed to support importing (exporting) symbols from (to)
632 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]633
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]634<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]635 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]636 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]637 or variable via a global pointer to a pointer that is set up by the DLL
638 exporting the symbol. On Microsoft Windows targets, the pointer name is
639 formed by combining <code>__imp_</code> and the function or variable
640 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]641
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]642 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]643 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]644 pointer to a pointer in a DLL, so that it can be referenced with the
645 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
646 name is formed by combining <code>__imp_</code> and the function or
647 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]648</dl>
649
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]650<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
651 another module defined a "<tt>.LC0</tt>" variable and was linked with this
652 one, one of the two would be renamed, preventing a collision. Since
653 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
654 declarations), they are accessible outside of the current module.</p>
655
656<p>It is illegal for a function <i>declaration</i> to have any linkage type
657 other than "externally visible", <tt>dllimport</tt>
658 or <tt>extern_weak</tt>.</p>
659
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]660<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]661 or <tt>weak_odr</tt> linkages.</p>
662
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]663</div>
664
665<!-- ======================================================================= -->
666<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]667 <a name="callingconv">Calling Conventions</a>
668</div>
669
670<div class="doc_text">
671
672<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]673 and <a href="#i_invoke">invokes</a> can all have an optional calling
674 convention specified for the call. The calling convention of any pair of
675 dynamic caller/callee must match, or the behavior of the program is
676 undefined. The following calling conventions are supported by LLVM, and more
677 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]678
679<dl>
680 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]681 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]682 specified) matches the target C calling conventions. This calling
683 convention supports varargs function calls and tolerates some mismatch in
684 the declared prototype and implemented declaration of the function (as
685 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]686
687 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]688 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]689 (e.g. by passing things in registers). This calling convention allows the
690 target to use whatever tricks it wants to produce fast code for the
691 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]692 (Application Binary Interface).
693 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
694 when this convention is used.</a> This calling convention does not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]695 support varargs and requires the prototype of all callees to exactly match
696 the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]697
698 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]699 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]700 as possible under the assumption that the call is not commonly executed.
701 As such, these calls often preserve all registers so that the call does
702 not break any live ranges in the caller side. This calling convention
703 does not support varargs and requires the prototype of all callees to
704 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]705
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]706 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]708 target-specific calling conventions to be used. Target specific calling
709 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]710</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]711
712<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]713 support Pascal conventions or any other well-known target-independent
714 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]715
716</div>
717
718<!-- ======================================================================= -->
719<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]720 <a name="visibility">Visibility Styles</a>
721</div>
722
723<div class="doc_text">
724
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]725<p>All Global Variables and Functions have one of the following visibility
726 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]727
728<dl>
729 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]730 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]731 that the declaration is visible to other modules and, in shared libraries,
732 means that the declared entity may be overridden. On Darwin, default
733 visibility means that the declaration is visible to other modules. Default
734 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]735
736 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]737 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]738 object if they are in the same shared object. Usually, hidden visibility
739 indicates that the symbol will not be placed into the dynamic symbol
740 table, so no other module (executable or shared library) can reference it
741 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]742
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]743 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]744 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]745 the dynamic symbol table, but that references within the defining module
746 will bind to the local symbol. That is, the symbol cannot be overridden by
747 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]748</dl>
749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]754 <a name="namedtypes">Named Types</a>
755</div>
756
757<div class="doc_text">
758
759<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]760 it easier to read the IR and make the IR more condensed (particularly when
761 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]762
763<div class="doc_code">
764<pre>
765%mytype = type { %mytype*, i32 }
766</pre>
767</div>
768
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]769<p>You may give a name to any <a href="#typesystem">type</a> except
770 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
771 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]772
773<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]774 and that you can therefore specify multiple names for the same type. This
775 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
776 uses structural typing, the name is not part of the type. When printing out
777 LLVM IR, the printer will pick <em>one name</em> to render all types of a
778 particular shape. This means that if you have code where two different
779 source types end up having the same LLVM type, that the dumper will sometimes
780 print the "wrong" or unexpected type. This is an important design point and
781 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]782
783</div>
784
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]785<!-- ======================================================================= -->
786<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]787 <a name="globalvars">Global Variables</a>
788</div>
789
790<div class="doc_text">
791
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]792<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]793 instead of run-time. Global variables may optionally be initialized, may
794 have an explicit section to be placed in, and may have an optional explicit
795 alignment specified. A variable may be defined as "thread_local", which
796 means that it will not be shared by threads (each thread will have a
797 separated copy of the variable). A variable may be defined as a global
798 "constant," which indicates that the contents of the variable
799 will <b>never</b> be modified (enabling better optimization, allowing the
800 global data to be placed in the read-only section of an executable, etc).
801 Note that variables that need runtime initialization cannot be marked
802 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]803
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]804<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
805 constant, even if the final definition of the global is not. This capability
806 can be used to enable slightly better optimization of the program, but
807 requires the language definition to guarantee that optimizations based on the
808 'constantness' are valid for the translation units that do not include the
809 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]810
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]811<p>As SSA values, global variables define pointer values that are in scope
812 (i.e. they dominate) all basic blocks in the program. Global variables
813 always define a pointer to their "content" type because they describe a
814 region of memory, and all memory objects in LLVM are accessed through
815 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]816
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]817<p>A global variable may be declared to reside in a target-specific numbered
818 address space. For targets that support them, address spaces may affect how
819 optimizations are performed and/or what target instructions are used to
820 access the variable. The default address space is zero. The address space
821 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]822
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]823<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]824 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]825
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]826<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]827 the alignment is set to zero, the alignment of the global is set by the
828 target to whatever it feels convenient. If an explicit alignment is
829 specified, the global is forced to have at least that much alignment. All
830 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]831
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]832<p>For example, the following defines a global in a numbered address space with
833 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]834
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]835<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]836<pre>
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]837@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]838</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]839</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]840
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]841</div>
842
843
844<!-- ======================================================================= -->
845<div class="doc_subsection">
846 <a name="functionstructure">Functions</a>
847</div>
848
849<div class="doc_text">
850
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]851<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
852 optional <a href="#linkage">linkage type</a>, an optional
853 <a href="#visibility">visibility style</a>, an optional
854 <a href="#callingconv">calling convention</a>, a return type, an optional
855 <a href="#paramattrs">parameter attribute</a> for the return type, a function
856 name, a (possibly empty) argument list (each with optional
857 <a href="#paramattrs">parameter attributes</a>), optional
858 <a href="#fnattrs">function attributes</a>, an optional section, an optional
859 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
860 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]861
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]862<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
863 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]864 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]865 <a href="#callingconv">calling convention</a>, a return type, an optional
866 <a href="#paramattrs">parameter attribute</a> for the return type, a function
867 name, a possibly empty list of arguments, an optional alignment, and an
868 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]869
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]870<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]871 (Control Flow Graph) for the function. Each basic block may optionally start
872 with a label (giving the basic block a symbol table entry), contains a list
873 of instructions, and ends with a <a href="#terminators">terminator</a>
874 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]875
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]876<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]877 executed on entrance to the function, and it is not allowed to have
878 predecessor basic blocks (i.e. there can not be any branches to the entry
879 block of a function). Because the block can have no predecessors, it also
880 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]881
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]882<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]883 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]884
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]885<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]886 the alignment is set to zero, the alignment of the function is set by the
887 target to whatever it feels convenient. If an explicit alignment is
888 specified, the function is forced to have at least that much alignment. All
889 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]890
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]891<h5>Syntax:</h5>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]892<div class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]893<pre>
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]894define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]895 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
896 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
897 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
898 [<a href="#gc">gc</a>] { ... }
899</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]900</div>
901
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]902</div>
903
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]904<!-- ======================================================================= -->
905<div class="doc_subsection">
906 <a name="aliasstructure">Aliases</a>
907</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]908
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]909<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]910
911<p>Aliases act as "second name" for the aliasee value (which can be either
912 function, global variable, another alias or bitcast of global value). Aliases
913 may have an optional <a href="#linkage">linkage type</a>, and an
914 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]915
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]916<h5>Syntax:</h5>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]917<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]918<pre>
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]919@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]920</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]921</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]922
923</div>
924
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]925<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]926<div class="doc_subsection">
927 <a name="namedmetadatastructure">Named Metadata</a>
928</div>
929
930<div class="doc_text">
931
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]932<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
933 nodes</a> (but not metadata strings) and null are the only valid operands for
934 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]935
936<h5>Syntax:</h5>
937<div class="doc_code">
938<pre>
939!1 = metadata !{metadata !"one"}
940!name = !{null, !1}
941</pre>
942</div>
943
944</div>
945
946<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]947<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]948
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]949<div class="doc_text">
950
951<p>The return type and each parameter of a function type may have a set of
952 <i>parameter attributes</i> associated with them. Parameter attributes are
953 used to communicate additional information about the result or parameters of
954 a function. Parameter attributes are considered to be part of the function,
955 not of the function type, so functions with different parameter attributes
956 can have the same function type.</p>
957
958<p>Parameter attributes are simple keywords that follow the type specified. If
959 multiple parameter attributes are needed, they are space separated. For
960 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]961
962<div class="doc_code">
963<pre>
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]964declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]965declare i32 @atoi(i8 zeroext)
966declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]967</pre>
968</div>
969
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]970<p>Note that any attributes for the function result (<tt>nounwind</tt>,
971 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]972
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]973<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]974
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]975<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]976 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]977 <dd>This indicates to the code generator that the parameter or return value
978 should be zero-extended to a 32-bit value by the caller (for a parameter)
979 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]980
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]981 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]982 <dd>This indicates to the code generator that the parameter or return value
983 should be sign-extended to a 32-bit value by the caller (for a parameter)
984 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]985
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]986 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]987 <dd>This indicates that this parameter or return value should be treated in a
988 special target-dependent fashion during while emitting code for a function
989 call or return (usually, by putting it in a register as opposed to memory,
990 though some targets use it to distinguish between two different kinds of
991 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]992
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]993 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]994 <dd>This indicates that the pointer parameter should really be passed by value
995 to the function. The attribute implies that a hidden copy of the pointee
996 is made between the caller and the callee, so the callee is unable to
997 modify the value in the callee. This attribute is only valid on LLVM
998 pointer arguments. It is generally used to pass structs and arrays by
999 value, but is also valid on pointers to scalars. The copy is considered
1000 to belong to the caller not the callee (for example,
1001 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1002 <tt>byval</tt> parameters). This is not a valid attribute for return
1003 values. The byval attribute also supports specifying an alignment with
1004 the align attribute. This has a target-specific effect on the code
1005 generator that usually indicates a desired alignment for the synthesized
1006 stack slot.</dd>
1007
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1008 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1009 <dd>This indicates that the pointer parameter specifies the address of a
1010 structure that is the return value of the function in the source program.
1011 This pointer must be guaranteed by the caller to be valid: loads and
1012 stores to the structure may be assumed by the callee to not to trap. This
1013 may only be applied to the first parameter. This is not a valid attribute
1014 for return values. </dd>
1015
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1016 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1017 <dd>This indicates that the pointer does not alias any global or any other
1018 parameter. The caller is responsible for ensuring that this is the
1019 case. On a function return value, <tt>noalias</tt> additionally indicates
1020 that the pointer does not alias any other pointers visible to the
1021 caller. For further details, please see the discussion of the NoAlias
1022 response in
1023 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1024 analysis</a>.</dd>
1025
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1026 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1027 <dd>This indicates that the callee does not make any copies of the pointer
1028 that outlive the callee itself. This is not a valid attribute for return
1029 values.</dd>
1030
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1031 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1032 <dd>This indicates that the pointer parameter can be excised using the
1033 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1034 attribute for return values.</dd>
1035</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1036
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1037</div>
1038
1039<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1040<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1041 <a name="gc">Garbage Collector Names</a>
1042</div>
1043
1044<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1045
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1046<p>Each function may specify a garbage collector name, which is simply a
1047 string:</p>
1048
1049<div class="doc_code">
1050<pre>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1051define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1052</pre>
1053</div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1054
1055<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1056 collector which will cause the compiler to alter its output in order to
1057 support the named garbage collection algorithm.</p>
1058
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1059</div>
1060
1061<!-- ======================================================================= -->
1062<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1063 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1064</div>
1065
1066<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1067
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1068<p>Function attributes are set to communicate additional information about a
1069 function. Function attributes are considered to be part of the function, not
1070 of the function type, so functions with different parameter attributes can
1071 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1072
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1073<p>Function attributes are simple keywords that follow the type specified. If
1074 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1075
1076<div class="doc_code">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1077<pre>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1078define void @f() noinline { ... }
1079define void @f() alwaysinline { ... }
1080define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1081define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1082</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1083</div>
1084
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1085<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1086 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1087 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1088 the backend should forcibly align the stack pointer. Specify the
1089 desired alignment, which must be a power of two, in parentheses.
1090
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1091 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1092 <dd>This attribute indicates that the inliner should attempt to inline this
1093 function into callers whenever possible, ignoring any active inlining size
1094 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1095
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1096 <dt><tt><b>inlinehint</b></tt></dt>
1097 <dd>This attribute indicates that the source code contained a hint that inlining
1098 this function is desirable (such as the "inline" keyword in C/C++). It
1099 is just a hint; it imposes no requirements on the inliner.</dd>
1100
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1101 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1102 <dd>This attribute indicates that the inliner should never inline this
1103 function in any situation. This attribute may not be used together with
1104 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1105
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1106 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1107 <dd>This attribute suggests that optimization passes and code generator passes
1108 make choices that keep the code size of this function low, and otherwise
1109 do optimizations specifically to reduce code size.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1110
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1111 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1112 <dd>This function attribute indicates that the function never returns
1113 normally. This produces undefined behavior at runtime if the function
1114 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1115
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1116 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1117 <dd>This function attribute indicates that the function never returns with an
1118 unwind or exceptional control flow. If the function does unwind, its
1119 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1120
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1121 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1122 <dd>This attribute indicates that the function computes its result (or decides
1123 to unwind an exception) based strictly on its arguments, without
1124 dereferencing any pointer arguments or otherwise accessing any mutable
1125 state (e.g. memory, control registers, etc) visible to caller functions.
1126 It does not write through any pointer arguments
1127 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1128 changes any state visible to callers. This means that it cannot unwind
1129 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1130 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1131
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1132 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1133 <dd>This attribute indicates that the function does not write through any
1134 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1135 arguments) or otherwise modify any state (e.g. memory, control registers,
1136 etc) visible to caller functions. It may dereference pointer arguments
1137 and read state that may be set in the caller. A readonly function always
1138 returns the same value (or unwinds an exception identically) when called
1139 with the same set of arguments and global state. It cannot unwind an
1140 exception by calling the <tt>C++</tt> exception throwing methods, but may
1141 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1142
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This attribute indicates that the function should emit a stack smashing
1145 protector. It is in the form of a "canary"&mdash;a random value placed on
1146 the stack before the local variables that's checked upon return from the
1147 function to see if it has been overwritten. A heuristic is used to
1148 determine if a function needs stack protectors or not.<br>
1149<br>
1150 If a function that has an <tt>ssp</tt> attribute is inlined into a
1151 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1152 function will have an <tt>ssp</tt> attribute.</dd>
1153
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1154 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1155 <dd>This attribute indicates that the function should <em>always</em> emit a
1156 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1157 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1158<br>
1159 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1160 function that doesn't have an <tt>sspreq</tt> attribute or which has
1161 an <tt>ssp</tt> attribute, then the resulting function will have
1162 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1163
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1164 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1165 <dd>This attribute indicates that the code generator should not use a red
1166 zone, even if the target-specific ABI normally permits it.</dd>
1167
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1168 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1169 <dd>This attributes disables implicit floating point instructions.</dd>
1170
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This attribute disables prologue / epilogue emission for the function.
1173 This can have very system-specific consequences.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1174</dl>
1175
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1176</div>
1177
1178<!-- ======================================================================= -->
1179<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1180 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1181</div>
1182
1183<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1184
1185<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1186 the GCC "file scope inline asm" blocks. These blocks are internally
1187 concatenated by LLVM and treated as a single unit, but may be separated in
1188 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1189
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1190<div class="doc_code">
1191<pre>
1192module asm "inline asm code goes here"
1193module asm "more can go here"
1194</pre>
1195</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1196
1197<p>The strings can contain any character by escaping non-printable characters.
1198 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1199 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1200
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1201<p>The inline asm code is simply printed to the machine code .s file when
1202 assembly code is generated.</p>
1203
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1204</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1205
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1206<!-- ======================================================================= -->
1207<div class="doc_subsection">
1208 <a name="datalayout">Data Layout</a>
1209</div>
1210
1211<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1212
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1213<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1214 data is to be laid out in memory. The syntax for the data layout is
1215 simply:</p>
1216
1217<div class="doc_code">
1218<pre>
1219target datalayout = "<i>layout specification</i>"
1220</pre>
1221</div>
1222
1223<p>The <i>layout specification</i> consists of a list of specifications
1224 separated by the minus sign character ('-'). Each specification starts with
1225 a letter and may include other information after the letter to define some
1226 aspect of the data layout. The specifications accepted are as follows:</p>
1227
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1228<dl>
1229 <dt><tt>E</tt></dt>
1230 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1231 bits with the most significance have the lowest address location.</dd>
1232
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1233 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1234 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1235 the bits with the least significance have the lowest address
1236 location.</dd>
1237
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1238 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1239 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1240 <i>preferred</i> alignments. All sizes are in bits. Specifying
1241 the <i>pref</i> alignment is optional. If omitted, the
1242 preceding <tt>:</tt> should be omitted too.</dd>
1243
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1244 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1245 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1246 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1247
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1248 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1249 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1250 <i>size</i>.</dd>
1251
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1252 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1253 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1254 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1255 (double).</dd>
1256
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1257 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1258 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1259 <i>size</i>.</dd>
1260
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1261 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1262 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1263 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1264
1265 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1266 <dd>This specifies a set of native integer widths for the target CPU
1267 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1268 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1269 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1270 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1271</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1272
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1273<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1274 default set of specifications which are then (possibly) overriden by the
1275 specifications in the <tt>datalayout</tt> keyword. The default specifications
1276 are given in this list:</p>
1277
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1278<ul>
1279 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame^]1280 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1281 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1282 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1283 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1284 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1285 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1286 alignment of 64-bits</li>
1287 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1288 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1289 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1290 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1291 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1292 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1293</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1294
1295<p>When LLVM is determining the alignment for a given type, it uses the
1296 following rules:</p>
1297
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1298<ol>
1299 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1300 specification is used.</li>
1301
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1302 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1303 smallest integer type that is larger than the bitwidth of the sought type
1304 is used. If none of the specifications are larger than the bitwidth then
1305 the the largest integer type is used. For example, given the default
1306 specifications above, the i7 type will use the alignment of i8 (next
1307 largest) while both i65 and i256 will use the alignment of i64 (largest
1308 specified).</li>
1309
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1310 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1311 largest vector type that is smaller than the sought vector type will be
1312 used as a fall back. This happens because &lt;128 x double&gt; can be
1313 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1314</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1315
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1316</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1317
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1318<!-- ======================================================================= -->
1319<div class="doc_subsection">
1320 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1321</div>
1322
1323<div class="doc_text">
1324
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1325<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1326with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1327is undefined. Pointer values are associated with address ranges
1328according to the following rules:</p>
1329
1330<ul>
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1331 <li>A pointer value formed from a
1332 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1333 is associated with the addresses associated with the first operand
1334 of the <tt>getelementptr</tt>.</li>
1335 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1336 range of the variable's storage.</li>
1337 <li>The result value of an allocation instruction is associated with
1338 the address range of the allocated storage.</li>
1339 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1340 no address.</li>
1341 <li>A pointer value formed by an
1342 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1343 address ranges of all pointer values that contribute (directly or
1344 indirectly) to the computation of the pointer's value.</li>
1345 <li>The result value of a
1346 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1347 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1348 <li>An integer constant other than zero or a pointer value returned
1349 from a function not defined within LLVM may be associated with address
1350 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1351 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1352 allocated by mechanisms provided by LLVM.</li>
1353 </ul>
1354
1355<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1356<tt><a href="#i_load">load</a></tt> merely indicates the size and
1357alignment of the memory from which to load, as well as the
1358interpretation of the value. The first operand of a
1359<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1360and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1361
1362<p>Consequently, type-based alias analysis, aka TBAA, aka
1363<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1364LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1365additional information which specialized optimization passes may use
1366to implement type-based alias analysis.</p>
1367
1368</div>
1369
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1370<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1371<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1372<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1373
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1374<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1375
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1376<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1377 intermediate representation. Being typed enables a number of optimizations
1378 to be performed on the intermediate representation directly, without having
1379 to do extra analyses on the side before the transformation. A strong type
1380 system makes it easier to read the generated code and enables novel analyses
1381 and transformations that are not feasible to perform on normal three address
1382 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1383
1384</div>
1385
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1386<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1387<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1388Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1389
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1390<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1391
1392<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1393
1394<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1395 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1396 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1397 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1398 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1399 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1400 </tr>
1401 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1402 <td><a href="#t_floating">floating point</a></td>
1403 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1404 </tr>
1405 <tr>
1406 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1407 <td><a href="#t_integer">integer</a>,
1408 <a href="#t_floating">floating point</a>,
1409 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1410 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1411 <a href="#t_struct">structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1412 <a href="#t_union">union</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1413 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1414 <a href="#t_label">label</a>,
1415 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1416 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1417 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1418 <tr>
1419 <td><a href="#t_primitive">primitive</a></td>
1420 <td><a href="#t_label">label</a>,
1421 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1422 <a href="#t_floating">floating point</a>,
1423 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1424 </tr>
1425 <tr>
1426 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1427 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1428 <a href="#t_function">function</a>,
1429 <a href="#t_pointer">pointer</a>,
1430 <a href="#t_struct">structure</a>,
1431 <a href="#t_pstruct">packed structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1432 <a href="#t_union">union</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1433 <a href="#t_vector">vector</a>,
1434 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1435 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1436 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1437 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1438</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1439
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1440<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1441 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1442 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1443
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1444</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1445
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1446<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1447<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1448
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1449<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1450
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1451<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1452 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1453
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1454</div>
1455
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1456<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1457<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1458
1459<div class="doc_text">
1460
1461<h5>Overview:</h5>
1462<p>The integer type is a very simple type that simply specifies an arbitrary
1463 bit width for the integer type desired. Any bit width from 1 bit to
1464 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1465
1466<h5>Syntax:</h5>
1467<pre>
1468 iN
1469</pre>
1470
1471<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1472 value.</p>
1473
1474<h5>Examples:</h5>
1475<table class="layout">
1476 <tr class="layout">
1477 <td class="left"><tt>i1</tt></td>
1478 <td class="left">a single-bit integer.</td>
1479 </tr>
1480 <tr class="layout">
1481 <td class="left"><tt>i32</tt></td>
1482 <td class="left">a 32-bit integer.</td>
1483 </tr>
1484 <tr class="layout">
1485 <td class="left"><tt>i1942652</tt></td>
1486 <td class="left">a really big integer of over 1 million bits.</td>
1487 </tr>
1488</table>
1489
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1490</div>
1491
1492<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1493<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1494
1495<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1496
1497<table>
1498 <tbody>
1499 <tr><th>Type</th><th>Description</th></tr>
1500 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1501 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1502 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1503 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1504 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1505 </tbody>
1506</table>
1507
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1508</div>
1509
1510<!-- _______________________________________________________________________ -->
1511<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1512
1513<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1514
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1515<h5>Overview:</h5>
1516<p>The void type does not represent any value and has no size.</p>
1517
1518<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1519<pre>
1520 void
1521</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1522
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1523</div>
1524
1525<!-- _______________________________________________________________________ -->
1526<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1527
1528<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1529
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1530<h5>Overview:</h5>
1531<p>The label type represents code labels.</p>
1532
1533<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1534<pre>
1535 label
1536</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1537
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1538</div>
1539
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1540<!-- _______________________________________________________________________ -->
1541<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1542
1543<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1544
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1545<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1546<p>The metadata type represents embedded metadata. No derived types may be
1547 created from metadata except for <a href="#t_function">function</a>
1548 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1549
1550<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1551<pre>
1552 metadata
1553</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1554
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1555</div>
1556
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1557
1558<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1559<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1560
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1561<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1562
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1563<p>The real power in LLVM comes from the derived types in the system. This is
1564 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1565 useful types. Each of these types contain one or more element types which
1566 may be a primitive type, or another derived type. For example, it is
1567 possible to have a two dimensional array, using an array as the element type
1568 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1569
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1570
1571</div>
1572
1573<!-- _______________________________________________________________________ -->
1574<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1575
1576<div class="doc_text">
1577
1578<p>Aggregate Types are a subset of derived types that can contain multiple
1579 member types. <a href="#t_array">Arrays</a>,
1580 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1581 <a href="#t_union">unions</a> are aggregate types.</p>
1582
1583</div>
1584
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1585</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1586
1587<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1588<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1589
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1590<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1591
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1592<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1593<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1594 sequentially in memory. The array type requires a size (number of elements)
1595 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1596
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1597<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1598<pre>
1599 [&lt;# elements&gt; x &lt;elementtype&gt;]
1600</pre>
1601
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1602<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1603 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1604
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1605<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1606<table class="layout">
1607 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1608 <td class="left"><tt>[40 x i32]</tt></td>
1609 <td class="left">Array of 40 32-bit integer values.</td>
1610 </tr>
1611 <tr class="layout">
1612 <td class="left"><tt>[41 x i32]</tt></td>
1613 <td class="left">Array of 41 32-bit integer values.</td>
1614 </tr>
1615 <tr class="layout">
1616 <td class="left"><tt>[4 x i8]</tt></td>
1617 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1618 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1619</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1620<p>Here are some examples of multidimensional arrays:</p>
1621<table class="layout">
1622 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1623 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1624 <td class="left">3x4 array of 32-bit integer values.</td>
1625 </tr>
1626 <tr class="layout">
1627 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1628 <td class="left">12x10 array of single precision floating point values.</td>
1629 </tr>
1630 <tr class="layout">
1631 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1632 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1633 </tr>
1634</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1635
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1636<p>There is no restriction on indexing beyond the end of the array implied by
1637 a static type (though there are restrictions on indexing beyond the bounds
1638 of an allocated object in some cases). This means that single-dimension
1639 'variable sized array' addressing can be implemented in LLVM with a zero
1640 length array type. An implementation of 'pascal style arrays' in LLVM could
1641 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1642
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1643</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1644
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1645<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1646<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1647
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1648<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1649
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1650<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1651<p>The function type can be thought of as a function signature. It consists of
1652 a return type and a list of formal parameter types. The return type of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1653 function type is a scalar type, a void type, a struct type, or a union
1654 type. If the return type is a struct type then all struct elements must be
1655 of first class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1656
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1657<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1658<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1659 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1660</pre>
1661
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1662<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1663 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1664 which indicates that the function takes a variable number of arguments.
1665 Variable argument functions can access their arguments with
1666 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1667 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1668 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1669
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1670<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1671<table class="layout">
1672 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1673 <td class="left"><tt>i32 (i32)</tt></td>
1674 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1675 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1676 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1677 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1678 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1679 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1680 an <tt>i16</tt> that should be sign extended and a
1681 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1682 <tt>float</tt>.
1683 </td>
1684 </tr><tr class="layout">
1685 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1686 <td class="left">A vararg function that takes at least one
1687 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1688 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1689 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1690 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1691 </tr><tr class="layout">
1692 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1693 <td class="left">A function taking an <tt>i32</tt>, returning a
1694 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1695 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1696 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1697</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1698
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1699</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1700
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1701<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1702<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1703
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1704<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1705
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1706<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1707<p>The structure type is used to represent a collection of data members together
1708 in memory. The packing of the field types is defined to match the ABI of the
1709 underlying processor. The elements of a structure may be any type that has a
1710 size.</p>
1711
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1712<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1713 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1714 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1715 Structures in registers are accessed using the
1716 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1717 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1718<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1719<pre>
1720 { &lt;type list&gt; }
1721</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1722
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1723<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1724<table class="layout">
1725 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1726 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1727 <td class="left">A triple of three <tt>i32</tt> values</td>
1728 </tr><tr class="layout">
1729 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1730 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1731 second element is a <a href="#t_pointer">pointer</a> to a
1732 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1733 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1734 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1735</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1736
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1737</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1738
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1739<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1740<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1741</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1742
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1743<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1744
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1745<h5>Overview:</h5>
1746<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1747 together in memory. There is no padding between fields. Further, the
1748 alignment of a packed structure is 1 byte. The elements of a packed
1749 structure may be any type that has a size.</p>
1750
1751<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1752 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1753 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1754
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1755<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1756<pre>
1757 &lt; { &lt;type list&gt; } &gt;
1758</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1759
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1760<h5>Examples:</h5>
1761<table class="layout">
1762 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1763 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1764 <td class="left">A triple of three <tt>i32</tt> values</td>
1765 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1766 <td class="left">
1767<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1768 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1769 second element is a <a href="#t_pointer">pointer</a> to a
1770 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1771 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1772 </tr>
1773</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1774
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1775</div>
1776
1777<!-- _______________________________________________________________________ -->
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1778<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1779
1780<div class="doc_text">
1781
1782<h5>Overview:</h5>
1783<p>A union type describes an object with size and alignment suitable for
1784 an object of any one of a given set of types (also known as an "untagged"
1785 union). It is similar in concept and usage to a
1786 <a href="#t_struct">struct</a>, except that all members of the union
1787 have an offset of zero. The elements of a union may be any type that has a
1788 size. Unions must have at least one member - empty unions are not allowed.
1789 </p>
1790
1791<p>The size of the union as a whole will be the size of its largest member,
1792 and the alignment requirements of the union as a whole will be the largest
1793 alignment requirement of any member.</p>
1794
1795<p>Unions members are accessed using '<tt><a href="#i_load">load</a></tt> and
1796 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1797 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1798 Since all members are at offset zero, the getelementptr instruction does
1799 not affect the address, only the type of the resulting pointer.</p>
1800
1801<h5>Syntax:</h5>
1802<pre>
1803 union { &lt;type list&gt; }
1804</pre>
1805
1806<h5>Examples:</h5>
1807<table class="layout">
1808 <tr class="layout">
1809 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1810 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1811 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1812 </tr><tr class="layout">
1813 <td class="left">
1814 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1815 <td class="left">A union, where the first element is a <tt>float</tt> and the
1816 second element is a <a href="#t_pointer">pointer</a> to a
1817 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1818 an <tt>i32</tt>.</td>
1819 </tr>
1820</table>
1821
1822</div>
1823
1824<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1825<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1826
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1827<div class="doc_text">
1828
1829<h5>Overview:</h5>
1830<p>As in many languages, the pointer type represents a pointer or reference to
1831 another object, which must live in memory. Pointer types may have an optional
1832 address space attribute defining the target-specific numbered address space
1833 where the pointed-to object resides. The default address space is zero.</p>
1834
1835<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1836 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1837
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1838<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1839<pre>
1840 &lt;type&gt; *
1841</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1842
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1843<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1844<table class="layout">
1845 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1846 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1847 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1848 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1849 </tr>
1850 <tr class="layout">
1851 <td class="left"><tt>i32 (i32 *) *</tt></td>
1852 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1853 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1854 <tt>i32</tt>.</td>
1855 </tr>
1856 <tr class="layout">
1857 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1858 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1859 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1860 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1861</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1862
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1863</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1864
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1865<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1866<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1867
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1868<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1869
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1870<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1871<p>A vector type is a simple derived type that represents a vector of elements.
1872 Vector types are used when multiple primitive data are operated in parallel
1873 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1874 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1875 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1876
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1877<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1878<pre>
1879 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1880</pre>
1881
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1882<p>The number of elements is a constant integer value; elementtype may be any
1883 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1884
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1885<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1886<table class="layout">
1887 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1888 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1889 <td class="left">Vector of 4 32-bit integer values.</td>
1890 </tr>
1891 <tr class="layout">
1892 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1893 <td class="left">Vector of 8 32-bit floating-point values.</td>
1894 </tr>
1895 <tr class="layout">
1896 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1897 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1898 </tr>
1899</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1900
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1901</div>
1902
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1903<!-- _______________________________________________________________________ -->
1904<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1905<div class="doc_text">
1906
1907<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1908<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1909 corresponds (for example) to the C notion of a forward declared structure
1910 type. In LLVM, opaque types can eventually be resolved to any type (not just
1911 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1912
1913<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1914<pre>
1915 opaque
1916</pre>
1917
1918<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1919<table class="layout">
1920 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1921 <td class="left"><tt>opaque</tt></td>
1922 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1923 </tr>
1924</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1925
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1926</div>
1927
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1928<!-- ======================================================================= -->
1929<div class="doc_subsection">
1930 <a name="t_uprefs">Type Up-references</a>
1931</div>
1932
1933<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1934
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1935<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1936<p>An "up reference" allows you to refer to a lexically enclosing type without
1937 requiring it to have a name. For instance, a structure declaration may
1938 contain a pointer to any of the types it is lexically a member of. Example
1939 of up references (with their equivalent as named type declarations)
1940 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1941
1942<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1943 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1944 { \2 }* %y = type { %y }*
1945 \1* %z = type %z*
1946</pre>
1947
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1948<p>An up reference is needed by the asmprinter for printing out cyclic types
1949 when there is no declared name for a type in the cycle. Because the
1950 asmprinter does not want to print out an infinite type string, it needs a
1951 syntax to handle recursive types that have no names (all names are optional
1952 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1953
1954<h5>Syntax:</h5>
1955<pre>
1956 \&lt;level&gt;
1957</pre>
1958
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1959<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]1960
1961<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1962<table class="layout">
1963 <tr class="layout">
1964 <td class="left"><tt>\1*</tt></td>
1965 <td class="left">Self-referential pointer.</td>
1966 </tr>
1967 <tr class="layout">
1968 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1969 <td class="left">Recursive structure where the upref refers to the out-most
1970 structure.</td>
1971 </tr>
1972</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1973
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1974</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1975
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1976<!-- *********************************************************************** -->
1977<div class="doc_section"> <a name="constants">Constants</a> </div>
1978<!-- *********************************************************************** -->
1979
1980<div class="doc_text">
1981
1982<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1983 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1984
1985</div>
1986
1987<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1988<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1989
1990<div class="doc_text">
1991
1992<dl>
1993 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1994 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1995 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1996
1997 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1998 <dd>Standard integers (such as '4') are constants of
1999 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2000 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2001
2002 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2003 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2004 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2005 notation (see below). The assembler requires the exact decimal value of a
2006 floating-point constant. For example, the assembler accepts 1.25 but
2007 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2008 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2009
2010 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2011 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2012 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2013</dl>
2014
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2015<p>The one non-intuitive notation for constants is the hexadecimal form of
2016 floating point constants. For example, the form '<tt>double
2017 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2018 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2019 constants are required (and the only time that they are generated by the
2020 disassembler) is when a floating point constant must be emitted but it cannot
2021 be represented as a decimal floating point number in a reasonable number of
2022 digits. For example, NaN's, infinities, and other special values are
2023 represented in their IEEE hexadecimal format so that assembly and disassembly
2024 do not cause any bits to change in the constants.</p>
2025
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2026<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2027 represented using the 16-digit form shown above (which matches the IEEE754
2028 representation for double); float values must, however, be exactly
2029 representable as IEE754 single precision. Hexadecimal format is always used
2030 for long double, and there are three forms of long double. The 80-bit format
2031 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2032 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2033 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2034 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2035 currently supported target uses this format. Long doubles will only work if
2036 they match the long double format on your target. All hexadecimal formats
2037 are big-endian (sign bit at the left).</p>
2038
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2039</div>
2040
2041<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2042<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2043<a name="aggregateconstants"></a> <!-- old anchor -->
2044<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2045</div>
2046
2047<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2048
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2049<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2050 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2051
2052<dl>
2053 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2054 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2055 type definitions (a comma separated list of elements, surrounded by braces
2056 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2057 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2058 Structure constants must have <a href="#t_struct">structure type</a>, and
2059 the number and types of elements must match those specified by the
2060 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2061
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2062 <dt><b>Union constants</b></dt>
2063 <dd>Union constants are represented with notation similar to a structure with
2064 a single element - that is, a single typed element surrounded
2065 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2066 <a href="#t_union">union type</a> can be initialized with a single-element
2067 struct as long as the type of the struct element matches the type of
2068 one of the union members.</dd>
2069
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2070 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2071 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2072 definitions (a comma separated list of elements, surrounded by square
2073 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2074 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2075 the number and types of elements must match those specified by the
2076 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2077
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2078 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2079 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2080 definitions (a comma separated list of elements, surrounded by
2081 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2082 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2083 have <a href="#t_vector">vector type</a>, and the number and types of
2084 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2085
2086 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2087 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2088 value to zero of <em>any</em> type, including scalar and
2089 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2090 This is often used to avoid having to print large zero initializers
2091 (e.g. for large arrays) and is always exactly equivalent to using explicit
2092 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2093
2094 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2095 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2096 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2097 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2098 be interpreted as part of the instruction stream, metadata is a place to
2099 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2100</dl>
2101
2102</div>
2103
2104<!-- ======================================================================= -->
2105<div class="doc_subsection">
2106 <a name="globalconstants">Global Variable and Function Addresses</a>
2107</div>
2108
2109<div class="doc_text">
2110
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2111<p>The addresses of <a href="#globalvars">global variables</a>
2112 and <a href="#functionstructure">functions</a> are always implicitly valid
2113 (link-time) constants. These constants are explicitly referenced when
2114 the <a href="#identifiers">identifier for the global</a> is used and always
2115 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2116 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2117
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2118<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2119<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2120@X = global i32 17
2121@Y = global i32 42
2122@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2123</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2124</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2125
2126</div>
2127
2128<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2129<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2130<div class="doc_text">
2131
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2132<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]2133 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2134 Undefined values may be of any type (other than label or void) and be used
2135 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2136
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2137<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2138 program is well defined no matter what value is used. This gives the
2139 compiler more freedom to optimize. Here are some examples of (potentially
2140 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2141
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2142
2143<div class="doc_code">
2144<pre>
2145 %A = add %X, undef
2146 %B = sub %X, undef
2147 %C = xor %X, undef
2148Safe:
2149 %A = undef
2150 %B = undef
2151 %C = undef
2152</pre>
2153</div>
2154
2155<p>This is safe because all of the output bits are affected by the undef bits.
2156Any output bit can have a zero or one depending on the input bits.</p>
2157
2158<div class="doc_code">
2159<pre>
2160 %A = or %X, undef
2161 %B = and %X, undef
2162Safe:
2163 %A = -1
2164 %B = 0
2165Unsafe:
2166 %A = undef
2167 %B = undef
2168</pre>
2169</div>
2170
2171<p>These logical operations have bits that are not always affected by the input.
2172For example, if "%X" has a zero bit, then the output of the 'and' operation will
2173always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2174such, 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]2175However, it is safe to assume that all bits of the undef could be 0, and
2176optimize the and to 0. Likewise, it is safe to assume that all the bits of
2177the 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]2178-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2179
2180<div class="doc_code">
2181<pre>
2182 %A = select undef, %X, %Y
2183 %B = select undef, 42, %Y
2184 %C = select %X, %Y, undef
2185Safe:
2186 %A = %X (or %Y)
2187 %B = 42 (or %Y)
2188 %C = %Y
2189Unsafe:
2190 %A = undef
2191 %B = undef
2192 %C = undef
2193</pre>
2194</div>
2195
2196<p>This set of examples show that undefined select (and conditional branch)
2197conditions can go "either way" but they have to come from one of the two
2198operands. In the %A example, if %X and %Y were both known to have a clear low
2199bit, then %A would have to have a cleared low bit. However, in the %C example,
2200the optimizer is allowed to assume that the undef operand could be the same as
2201%Y, allowing the whole select to be eliminated.</p>
2202
2203
2204<div class="doc_code">
2205<pre>
2206 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2207
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2208 %B = undef
2209 %C = xor %B, %B
2210
2211 %D = undef
2212 %E = icmp lt %D, 4
2213 %F = icmp gte %D, 4
2214
2215Safe:
2216 %A = undef
2217 %B = undef
2218 %C = undef
2219 %D = undef
2220 %E = undef
2221 %F = undef
2222</pre>
2223</div>
2224
2225<p>This example points out that two undef operands are not necessarily the same.
2226This can be surprising to people (and also matches C semantics) where they
2227assume that "X^X" is always zero, even if X is undef. This isn't true for a
2228number of reasons, but the short answer is that an undef "variable" can
2229arbitrarily change its value over its "live range". This is true because the
2230"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2231logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2232so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2233to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2234would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2235
2236<div class="doc_code">
2237<pre>
2238 %A = fdiv undef, %X
2239 %B = fdiv %X, undef
2240Safe:
2241 %A = undef
2242b: unreachable
2243</pre>
2244</div>
2245
2246<p>These examples show the crucial difference between an <em>undefined
2247value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2248allowed to have an arbitrary bit-pattern. This means that the %A operation
2249can be constant folded to undef because the undef could be an SNaN, and fdiv is
2250not (currently) defined on SNaN's. However, in the second example, we can make
2251a more aggressive assumption: because the undef is allowed to be an arbitrary
2252value, 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]2253has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2254does not execute at all. This allows us to delete the divide and all code after
2255it: since the undefined operation "can't happen", the optimizer can assume that
2256it occurs in dead code.
2257</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2258
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2259<div class="doc_code">
2260<pre>
2261a: store undef -> %X
2262b: store %X -> undef
2263Safe:
2264a: &lt;deleted&gt;
2265b: unreachable
2266</pre>
2267</div>
2268
2269<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2270can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2271overwritten with bits that happen to match what was already there. However, a
2272store "to" an undefined location could clobber arbitrary memory, therefore, it
2273has undefined behavior.</p>
2274
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2275</div>
2276
2277<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2278<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2279 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2280<div class="doc_text">
2281
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2282<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2283
2284<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2285 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2286 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2287
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2288<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2289 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2290 against null. Pointer equality tests between labels addresses is undefined
2291 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2292 equal to the null pointer. This may also be passed around as an opaque
2293 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2294 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2295 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2296
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2297<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2298 using the value as the operand to an inline assembly, but that is target
2299 specific.
2300 </p>
2301
2302</div>
2303
2304
2305<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2306<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2307</div>
2308
2309<div class="doc_text">
2310
2311<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2312 to be used as constants. Constant expressions may be of
2313 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2314 operation that does not have side effects (e.g. load and call are not
2315 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2316
2317<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2318 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2319 <dd>Truncate a constant to another type. The bit size of CST must be larger
2320 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2321
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2322 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2323 <dd>Zero extend a constant to another type. The bit size of CST must be
2324 smaller or equal to the bit size of TYPE. Both types must be
2325 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2326
2327 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2328 <dd>Sign extend a constant to another type. The bit size of CST must be
2329 smaller or equal to the bit size of TYPE. Both types must be
2330 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2331
2332 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2333 <dd>Truncate a floating point constant to another floating point type. The
2334 size of CST must be larger than the size of TYPE. Both types must be
2335 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2336
2337 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2338 <dd>Floating point extend a constant to another type. The size of CST must be
2339 smaller or equal to the size of TYPE. Both types must be floating
2340 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2341
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]2342 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2343 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2344 constant. TYPE must be a scalar or vector integer type. CST must be of
2345 scalar or vector floating point type. Both CST and TYPE must be scalars,
2346 or vectors of the same number of elements. If the value won't fit in the
2347 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2348
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2349 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2350 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2351 constant. TYPE must be a scalar or vector integer type. CST must be of
2352 scalar or vector floating point type. Both CST and TYPE must be scalars,
2353 or vectors of the same number of elements. If the value won't fit in the
2354 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2355
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2356 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2357 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2358 constant. TYPE must be a scalar or vector floating point type. CST must be
2359 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2360 vectors of the same number of elements. If the value won't fit in the
2361 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2362
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2363 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2364 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2365 constant. TYPE must be a scalar or vector floating point type. CST must be
2366 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2367 vectors of the same number of elements. If the value won't fit in the
2368 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2369
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2370 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2371 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2372 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2373 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2374 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2375
2376 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2377 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2378 type. CST must be of integer type. The CST value is zero extended,
2379 truncated, or unchanged to make it fit in a pointer size. This one is
2380 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2381
2382 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2383 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2384 are the same as those for the <a href="#i_bitcast">bitcast
2385 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2386
2387 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]2388 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2389 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2390 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2391 instruction, the index list may have zero or more indexes, which are
2392 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2393
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2394 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2395 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2396
2397 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2398 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2399
2400 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2401 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2402
2403 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2404 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2405 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2406
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]2407 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2408 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2409 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2410
2411 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2412 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2413 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2414
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2415 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2416 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2417 be any of the <a href="#binaryops">binary</a>
2418 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2419 on operands are the same as those for the corresponding instruction
2420 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2421</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2422
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2423</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2424
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2425<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2426<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2427<!-- *********************************************************************** -->
2428
2429<!-- ======================================================================= -->
2430<div class="doc_subsection">
2431<a name="inlineasm">Inline Assembler Expressions</a>
2432</div>
2433
2434<div class="doc_text">
2435
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2436<p>LLVM supports inline assembler expressions (as opposed
2437 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2438 a special value. This value represents the inline assembler as a string
2439 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2440 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2441 expression has side effects, and a flag indicating whether the function
2442 containing the asm needs to align its stack conservatively. An example
2443 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2444
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2445<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2446<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2447i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2448</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2449</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2450
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2451<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2452 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2453 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2454
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2455<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2456<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2457%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]2458</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2459</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2460
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2461<p>Inline asms with side effects not visible in the constraint list must be
2462 marked as having side effects. This is done through the use of the
2463 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2464
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2465<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2466<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2467call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2468</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2469</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2470
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2471<p>In some cases inline asms will contain code that will not work unless the
2472 stack is aligned in some way, such as calls or SSE instructions on x86,
2473 yet will not contain code that does that alignment within the asm.
2474 The compiler should make conservative assumptions about what the asm might
2475 contain and should generate its usual stack alignment code in the prologue
2476 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2477
2478<div class="doc_code">
2479<pre>
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2480call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2481</pre>
2482</div>
2483
2484<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2485 first.</p>
2486
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2487<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2488 documented here. Constraints on what can be done (e.g. duplication, moving,
2489 etc need to be documented). This is probably best done by reference to
2490 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2491
2492</div>
2493
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2494<!-- ======================================================================= -->
2495<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2496 Strings</a>
2497</div>
2498
2499<div class="doc_text">
2500
2501<p>LLVM IR allows metadata to be attached to instructions in the program that
2502 can convey extra information about the code to the optimizers and code
2503 generator. One example application of metadata is source-level debug
2504 information. There are two metadata primitives: strings and nodes. All
2505 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2506 preceding exclamation point ('<tt>!</tt>').</p>
2507
2508<p>A metadata string is a string surrounded by double quotes. It can contain
2509 any character by escaping non-printable characters with "\xx" where "xx" is
2510 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2511
2512<p>Metadata nodes are represented with notation similar to structure constants
2513 (a comma separated list of elements, surrounded by braces and preceded by an
2514 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2515 10}</tt>". Metadata nodes can have any values as their operand.</p>
2516
2517<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2518 metadata nodes, which can be looked up in the module symbol table. For
2519 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2520
2521</div>
2522
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2523
2524<!-- *********************************************************************** -->
2525<div class="doc_section">
2526 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2527</div>
2528<!-- *********************************************************************** -->
2529
2530<p>LLVM has a number of "magic" global variables that contain data that affect
2531code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2532of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2533section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2534by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2535
2536<!-- ======================================================================= -->
2537<div class="doc_subsection">
2538<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2539</div>
2540
2541<div class="doc_text">
2542
2543<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2544href="#linkage_appending">appending linkage</a>. This array contains a list of
2545pointers to global variables and functions which may optionally have a pointer
2546cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2547
2548<pre>
2549 @X = global i8 4
2550 @Y = global i32 123
2551
2552 @llvm.used = appending global [2 x i8*] [
2553 i8* @X,
2554 i8* bitcast (i32* @Y to i8*)
2555 ], section "llvm.metadata"
2556</pre>
2557
2558<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2559compiler, assembler, and linker are required to treat the symbol as if there is
2560a reference to the global that it cannot see. For example, if a variable has
2561internal linkage and no references other than that from the <tt>@llvm.used</tt>
2562list, it cannot be deleted. This is commonly used to represent references from
2563inline asms and other things the compiler cannot "see", and corresponds to
2564"attribute((used))" in GNU C.</p>
2565
2566<p>On some targets, the code generator must emit a directive to the assembler or
2567object file to prevent the assembler and linker from molesting the symbol.</p>
2568
2569</div>
2570
2571<!-- ======================================================================= -->
2572<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2573<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2574</div>
2575
2576<div class="doc_text">
2577
2578<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2579<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2580touching the symbol. On targets that support it, this allows an intelligent
2581linker to optimize references to the symbol without being impeded as it would be
2582by <tt>@llvm.used</tt>.</p>
2583
2584<p>This is a rare construct that should only be used in rare circumstances, and
2585should not be exposed to source languages.</p>
2586
2587</div>
2588
2589<!-- ======================================================================= -->
2590<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2591<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2592</div>
2593
2594<div class="doc_text">
2595
2596<p>TODO: Describe this.</p>
2597
2598</div>
2599
2600<!-- ======================================================================= -->
2601<div class="doc_subsection">
2602<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2603</div>
2604
2605<div class="doc_text">
2606
2607<p>TODO: Describe this.</p>
2608
2609</div>
2610
2611
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2612<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2613<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2614<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2615
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2616<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2617
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2618<p>The LLVM instruction set consists of several different classifications of
2619 instructions: <a href="#terminators">terminator
2620 instructions</a>, <a href="#binaryops">binary instructions</a>,
2621 <a href="#bitwiseops">bitwise binary instructions</a>,
2622 <a href="#memoryops">memory instructions</a>, and
2623 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2624
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2625</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2626
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2627<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2628<div class="doc_subsection"> <a name="terminators">Terminator
2629Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2630
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2631<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2632
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2633<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2634 in a program ends with a "Terminator" instruction, which indicates which
2635 block should be executed after the current block is finished. These
2636 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2637 control flow, not values (the one exception being the
2638 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2639
2640<p>There are six different terminator instructions: the
2641 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2642 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2643 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2644 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2645 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2646 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2647 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2648
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2649</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2650
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2651<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2652<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2653Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2654
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2655<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2656
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2657<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2658<pre>
2659 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]2660 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2661</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2662
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2663<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2664<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2665 a value) from a function back to the caller.</p>
2666
2667<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2668 value and then causes control flow, and one that just causes control flow to
2669 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2670
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2671<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2672<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2673 return value. The type of the return value must be a
2674 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2675
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2676<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2677 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2678 value or a return value with a type that does not match its type, or if it
2679 has a void return type and contains a '<tt>ret</tt>' instruction with a
2680 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2681
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2682<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2683<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2684 the calling function's context. If the caller is a
2685 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2686 instruction after the call. If the caller was an
2687 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2688 the beginning of the "normal" destination block. If the instruction returns
2689 a value, that value shall set the call or invoke instruction's return
2690 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2691
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2692<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2693<pre>
2694 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2695 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2696 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]2697</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2698
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2699</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2700<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2701<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2702
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2703<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2704
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2705<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2706<pre>
2707 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]2708</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2709
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2710<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2711<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2712 different basic block in the current function. There are two forms of this
2713 instruction, corresponding to a conditional branch and an unconditional
2714 branch.</p>
2715
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2716<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2717<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2718 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2719 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2720 target.</p>
2721
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2722<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2723<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2724 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2725 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2726 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2727
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2728<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2729<pre>
2730Test:
2731 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2732 br i1 %cond, label %IfEqual, label %IfUnequal
2733IfEqual:
2734 <a href="#i_ret">ret</a> i32 1
2735IfUnequal:
2736 <a href="#i_ret">ret</a> i32 0
2737</pre>
2738
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2739</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2740
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2741<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2742<div class="doc_subsubsection">
2743 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2744</div>
2745
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2746<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2747
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2748<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2749<pre>
2750 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2751</pre>
2752
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2753<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2754<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]2755 several different places. It is a generalization of the '<tt>br</tt>'
2756 instruction, allowing a branch to occur to one of many possible
2757 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2758
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2759<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2760<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2761 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2762 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2763 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2764
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2765<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2766<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2767 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2768 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2769 transferred to the corresponding destination; otherwise, control flow is
2770 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2771
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2772<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2773<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2774 <tt>switch</tt> instruction, this instruction may be code generated in
2775 different ways. For example, it could be generated as a series of chained
2776 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2777
2778<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2779<pre>
2780 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2781 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2782 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2783
2784 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2785 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2786
2787 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2788 switch i32 %val, label %otherwise [ i32 0, label %onzero
2789 i32 1, label %onone
2790 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2791</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2792
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2793</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2794
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2795
2796<!-- _______________________________________________________________________ -->
2797<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2798 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2799</div>
2800
2801<div class="doc_text">
2802
2803<h5>Syntax:</h5>
2804<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2805 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]2806</pre>
2807
2808<h5>Overview:</h5>
2809
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2810<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2811 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2812 "<tt>address</tt>". Address must be derived from a <a
2813 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2814
2815<h5>Arguments:</h5>
2816
2817<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2818 rest of the arguments indicate the full set of possible destinations that the
2819 address may point to. Blocks are allowed to occur multiple times in the
2820 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2821
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2822<p>This destination list is required so that dataflow analysis has an accurate
2823 understanding of the CFG.</p>
2824
2825<h5>Semantics:</h5>
2826
2827<p>Control transfers to the block specified in the address argument. All
2828 possible destination blocks must be listed in the label list, otherwise this
2829 instruction has undefined behavior. This implies that jumps to labels
2830 defined in other functions have undefined behavior as well.</p>
2831
2832<h5>Implementation:</h5>
2833
2834<p>This is typically implemented with a jump through a register.</p>
2835
2836<h5>Example:</h5>
2837<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2838 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2839</pre>
2840
2841</div>
2842
2843
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2844<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2845<div class="doc_subsubsection">
2846 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2847</div>
2848
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2849<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2850
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2851<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2852<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2853 &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]2854 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2855</pre>
2856
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2857<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2858<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2859 function, with the possibility of control flow transfer to either the
2860 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2861 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2862 control flow will return to the "normal" label. If the callee (or any
2863 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2864 instruction, control is interrupted and continued at the dynamically nearest
2865 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2866
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2867<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2868<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2869
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2870<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2871 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2872 convention</a> the call should use. If none is specified, the call
2873 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2874
2875 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2876 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2877 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2878
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2879 <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]2880 function value being invoked. In most cases, this is a direct function
2881 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2882 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2883
2884 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2885 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2886
2887 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2888 signature argument types. If the function signature indicates the
2889 function accepts a variable number of arguments, the extra arguments can
2890 be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2891
2892 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2893 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2894
2895 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2896 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2897
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2898 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2899 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2900 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2901</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2902
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2903<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2904<p>This instruction is designed to operate as a standard
2905 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2906 primary difference is that it establishes an association with a label, which
2907 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2908
2909<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2910 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2911 exception. Additionally, this is important for implementation of
2912 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2913
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2914<p>For the purposes of the SSA form, the definition of the value returned by the
2915 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2916 block to the "normal" label. If the callee unwinds then no return value is
2917 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]2918
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]2919<p>Note that the code generator does not yet completely support unwind, and
2920that the invoke/unwind semantics are likely to change in future versions.</p>
2921
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2922<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2923<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2924 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2925 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2926 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2927 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2928</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2929
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2930</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2931
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2932<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2933
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2934<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2935Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2936
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2937<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2938
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2939<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2940<pre>
2941 unwind
2942</pre>
2943
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2944<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2945<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2946 at the first callee in the dynamic call stack which used
2947 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2948 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2949
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2950<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2951<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2952 immediately halt. The dynamic call stack is then searched for the
2953 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2954 Once found, execution continues at the "exceptional" destination block
2955 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2956 instruction in the dynamic call chain, undefined behavior results.</p>
2957
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]2958<p>Note that the code generator does not yet completely support unwind, and
2959that the invoke/unwind semantics are likely to change in future versions.</p>
2960
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2961</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2962
2963<!-- _______________________________________________________________________ -->
2964
2965<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2966Instruction</a> </div>
2967
2968<div class="doc_text">
2969
2970<h5>Syntax:</h5>
2971<pre>
2972 unreachable
2973</pre>
2974
2975<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2976<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2977 instruction is used to inform the optimizer that a particular portion of the
2978 code is not reachable. This can be used to indicate that the code after a
2979 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2980
2981<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2982<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2983
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2984</div>
2985
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2986<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2987<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2988
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2989<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2990
2991<p>Binary operators are used to do most of the computation in a program. They
2992 require two operands of the same type, execute an operation on them, and
2993 produce a single value. The operands might represent multiple data, as is
2994 the case with the <a href="#t_vector">vector</a> data type. The result value
2995 has the same type as its operands.</p>
2996
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2997<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2998
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2999</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3000
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3001<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3002<div class="doc_subsubsection">
3003 <a name="i_add">'<tt>add</tt>' Instruction</a>
3004</div>
3005
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3006<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3007
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3008<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3009<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3010 &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]3011 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3012 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3013 &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]3014</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3015
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3016<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3017<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3018
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3019<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3020<p>The two arguments to the '<tt>add</tt>' instruction must
3021 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3022 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3023
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3024<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3025<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3026
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3027<p>If the sum has unsigned overflow, the result returned is the mathematical
3028 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]3029
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3030<p>Because LLVM integers use a two's complement representation, this instruction
3031 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3032
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3033<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3034 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3035 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
3036 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3037
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3038<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3039<pre>
3040 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3041</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3042
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3043</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3044
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3045<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3046<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3047 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3048</div>
3049
3050<div class="doc_text">
3051
3052<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3053<pre>
3054 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3055</pre>
3056
3057<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3058<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3059
3060<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3061<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3062 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3063 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3064
3065<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3066<p>The value produced is the floating point sum of the two operands.</p>
3067
3068<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3069<pre>
3070 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3071</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3072
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3073</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3074
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3075<!-- _______________________________________________________________________ -->
3076<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3077 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3078</div>
3079
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3080<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3081
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3082<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3083<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3084 &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]3085 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3086 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3087 &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]3088</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3089
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3090<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3091<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3092 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3093
3094<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3095 '<tt>neg</tt>' instruction present in most other intermediate
3096 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3097
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3098<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3099<p>The two arguments to the '<tt>sub</tt>' instruction must
3100 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3101 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3102
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3103<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3104<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3105
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3106<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3107 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3108 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3109
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3110<p>Because LLVM integers use a two's complement representation, this instruction
3111 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3112
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3113<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3114 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3115 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3116 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3117
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3118<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3119<pre>
3120 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3121 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3122</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3123
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3124</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3125
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3126<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3127<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3128 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3129</div>
3130
3131<div class="doc_text">
3132
3133<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3134<pre>
3135 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3136</pre>
3137
3138<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3139<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3140 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3141
3142<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3143 '<tt>fneg</tt>' instruction present in most other intermediate
3144 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3145
3146<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3147<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3148 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3149 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3150
3151<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3152<p>The value produced is the floating point difference of the two operands.</p>
3153
3154<h5>Example:</h5>
3155<pre>
3156 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3157 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3158</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3159
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3160</div>
3161
3162<!-- _______________________________________________________________________ -->
3163<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3164 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3165</div>
3166
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3167<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3168
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3169<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3170<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3171 &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]3172 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3173 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3174 &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]3175</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3176
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3177<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3178<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3179
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3180<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3181<p>The two arguments to the '<tt>mul</tt>' instruction must
3182 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3183 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3184
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3185<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3186<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3187
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3188<p>If the result of the multiplication has unsigned overflow, the result
3189 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3190 width of the result.</p>
3191
3192<p>Because LLVM integers use a two's complement representation, and the result
3193 is the same width as the operands, this instruction returns the correct
3194 result for both signed and unsigned integers. If a full product
3195 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3196 be sign-extended or zero-extended as appropriate to the width of the full
3197 product.</p>
3198
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3199<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3200 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3201 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3202 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3203
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3204<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3205<pre>
3206 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3207</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3208
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3209</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3210
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3211<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3212<div class="doc_subsubsection">
3213 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3214</div>
3215
3216<div class="doc_text">
3217
3218<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3219<pre>
3220 &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]3221</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3222
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3223<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3224<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3225
3226<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3227<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3228 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3229 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3230
3231<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3232<p>The value produced is the floating point product of the two operands.</p>
3233
3234<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3235<pre>
3236 &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]3237</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3238
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3239</div>
3240
3241<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3242<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3243</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3244
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3245<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3246
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3247<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3248<pre>
3249 &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]3250</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3251
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3252<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3253<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3254
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3255<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3256<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3257 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3258 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3259
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3260<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3261<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3262
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3263<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3264 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3265
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3266<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3267
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3268<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3269<pre>
3270 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3271</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3272
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3273</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3274
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3275<!-- _______________________________________________________________________ -->
3276<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3277</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3278
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3279<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3280
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3281<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3282<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3283 &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]3284 &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]3285</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3286
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3287<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3288<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3289
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3290<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3291<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3292 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3293 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3294
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3295<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3296<p>The value produced is the signed integer quotient of the two operands rounded
3297 towards zero.</p>
3298
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3299<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3300 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3301
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3302<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3303 undefined behavior; this is a rare case, but can occur, for example, by doing
3304 a 32-bit division of -2147483648 by -1.</p>
3305
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3306<p>If the <tt>exact</tt> keyword is present, the result value of the
3307 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3308 would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3309
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3310<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3311<pre>
3312 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3313</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3314
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3315</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3316
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3317<!-- _______________________________________________________________________ -->
3318<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3319Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3320
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3321<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3322
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3323<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3324<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3325 &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]3326</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3327
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3328<h5>Overview:</h5>
3329<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3330
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3331<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3332<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3333 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3334 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3335
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3336<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3337<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3338
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3339<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3340<pre>
3341 &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]3342</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3343
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3344</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3345
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3346<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3347<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3348</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3349
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3350<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3351
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3352<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3353<pre>
3354 &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]3355</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3356
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3357<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3358<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3359 division of its two arguments.</p>
3360
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3361<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3362<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3363 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3364 values. Both arguments must have identical types.</p>
3365
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3366<h5>Semantics:</h5>
3367<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3368 This instruction always performs an unsigned division to get the
3369 remainder.</p>
3370
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3371<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3372 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3373
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3374<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3375
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3376<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3377<pre>
3378 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3379</pre>
3380
3381</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3382
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3383<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3384<div class="doc_subsubsection">
3385 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3386</div>
3387
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3388<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3389
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3390<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3391<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3392 &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]3393</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3394
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3395<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3396<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3397 division of its two operands. This instruction can also take
3398 <a href="#t_vector">vector</a> versions of the values in which case the
3399 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3400
Chris Lattner48b383b02003-11-25 01:02:51 +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>srem</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>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3405
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3406<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3407<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3408 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3409 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3410 a value. For more information about the difference,
3411 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3412 Math Forum</a>. For a table of how this is implemented in various languages,
3413 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3414 Wikipedia: modulo operation</a>.</p>
3415
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3416<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3417 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3418
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3419<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3420 Overflow also leads to undefined behavior; this is a rare case, but can
3421 occur, for example, by taking the remainder of a 32-bit division of
3422 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3423 lets srem be implemented using instructions that return both the result of
3424 the division and the remainder.)</p>
3425
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3426<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3427<pre>
3428 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3429</pre>
3430
3431</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3432
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3433<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3434<div class="doc_subsubsection">
3435 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3436
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3437<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3438
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3439<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3440<pre>
3441 &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]3442</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3443
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3444<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3445<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3446 its two operands.</p>
3447
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3448<h5>Arguments:</h5>
3449<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3450 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3451 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3452
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3453<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3454<p>This instruction returns the <i>remainder</i> of a division. The remainder
3455 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3456
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3457<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3458<pre>
3459 &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]3460</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3461
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3462</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3463
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3464<!-- ======================================================================= -->
3465<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3466Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3467
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3468<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3469
3470<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3471 program. They are generally very efficient instructions and can commonly be
3472 strength reduced from other instructions. They require two operands of the
3473 same type, execute an operation on them, and produce a single value. The
3474 resulting value is the same type as its operands.</p>
3475
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3476</div>
3477
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3478<!-- _______________________________________________________________________ -->
3479<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3480Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3481
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3482<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3483
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3484<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3485<pre>
3486 &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]3487</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3488
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3489<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3490<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3491 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3492
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3493<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3494<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3495 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3496 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3497
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3498<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3499<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3500 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3501 is (statically or dynamically) negative or equal to or larger than the number
3502 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3503 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3504 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3505
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3506<h5>Example:</h5>
3507<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3508 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3509 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3510 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3511 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3512 &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]3513</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3514
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3515</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3516
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3517<!-- _______________________________________________________________________ -->
3518<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3519Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3520
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3521<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3522
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3523<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3524<pre>
3525 &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]3526</pre>
3527
3528<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3529<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3530 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3531
3532<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3533<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3534 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3535 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3536
3537<h5>Semantics:</h5>
3538<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3539 significant bits of the result will be filled with zero bits after the shift.
3540 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3541 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3542 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3543 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3544
3545<h5>Example:</h5>
3546<pre>
3547 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3548 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3549 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3550 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3551 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3552 &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]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>
3556
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3557<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3558<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3559Instruction</a> </div>
3560<div class="doc_text">
3561
3562<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3563<pre>
3564 &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]3565</pre>
3566
3567<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3568<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3569 operand shifted to the right a specified number of bits with sign
3570 extension.</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>ashr</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>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3578<p>This instruction always performs an arithmetic shift right operation, The
3579 most significant bits of the result will be filled with the sign bit
3580 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3581 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3582 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3583 the corresponding 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; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3588 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3589 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3590 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3591 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3592 &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]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
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3597<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3598<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3599Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3600
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3601<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3602
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3603<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3604<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3605 &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]3606</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3607
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3608<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3609<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3610 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3611
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3612<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3613<p>The two arguments to the '<tt>and</tt>' instruction must be
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 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3616
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3617<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3618<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3619
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3620<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3621 <tbody>
3622 <tr>
3623 <td>In0</td>
3624 <td>In1</td>
3625 <td>Out</td>
3626 </tr>
3627 <tr>
3628 <td>0</td>
3629 <td>0</td>
3630 <td>0</td>
3631 </tr>
3632 <tr>
3633 <td>0</td>
3634 <td>1</td>
3635 <td>0</td>
3636 </tr>
3637 <tr>
3638 <td>1</td>
3639 <td>0</td>
3640 <td>0</td>
3641 </tr>
3642 <tr>
3643 <td>1</td>
3644 <td>1</td>
3645 <td>1</td>
3646 </tr>
3647 </tbody>
3648</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3649
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3650<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3651<pre>
3652 &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]3653 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3654 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3655</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3656</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3657<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3658<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3659
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3660<div class="doc_text">
3661
3662<h5>Syntax:</h5>
3663<pre>
3664 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3665</pre>
3666
3667<h5>Overview:</h5>
3668<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3669 two operands.</p>
3670
3671<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3672<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3673 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3674 values. Both arguments must have identical types.</p>
3675
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3676<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3677<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3678
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3679<table border="1" cellspacing="0" cellpadding="4">
3680 <tbody>
3681 <tr>
3682 <td>In0</td>
3683 <td>In1</td>
3684 <td>Out</td>
3685 </tr>
3686 <tr>
3687 <td>0</td>
3688 <td>0</td>
3689 <td>0</td>
3690 </tr>
3691 <tr>
3692 <td>0</td>
3693 <td>1</td>
3694 <td>1</td>
3695 </tr>
3696 <tr>
3697 <td>1</td>
3698 <td>0</td>
3699 <td>1</td>
3700 </tr>
3701 <tr>
3702 <td>1</td>
3703 <td>1</td>
3704 <td>1</td>
3705 </tr>
3706 </tbody>
3707</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3708
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3709<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3710<pre>
3711 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3712 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3713 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3714</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3715
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3716</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3717
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3718<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3719<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3720Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3721
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3722<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3723
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3724<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3725<pre>
3726 &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]3727</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3728
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3729<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3730<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3731 its two operands. The <tt>xor</tt> is used to implement the "one's
3732 complement" operation, which is the "~" operator in C.</p>
3733
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3734<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3735<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3736 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3737 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3738
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3739<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3740<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3741
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3742<table border="1" cellspacing="0" cellpadding="4">
3743 <tbody>
3744 <tr>
3745 <td>In0</td>
3746 <td>In1</td>
3747 <td>Out</td>
3748 </tr>
3749 <tr>
3750 <td>0</td>
3751 <td>0</td>
3752 <td>0</td>
3753 </tr>
3754 <tr>
3755 <td>0</td>
3756 <td>1</td>
3757 <td>1</td>
3758 </tr>
3759 <tr>
3760 <td>1</td>
3761 <td>0</td>
3762 <td>1</td>
3763 </tr>
3764 <tr>
3765 <td>1</td>
3766 <td>1</td>
3767 <td>0</td>
3768 </tr>
3769 </tbody>
3770</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3771
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3772<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3773<pre>
3774 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3775 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3776 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3777 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3778</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3779
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3780</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3781
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3782<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3783<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3784 <a name="vectorops">Vector Operations</a>
3785</div>
3786
3787<div class="doc_text">
3788
3789<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3790 target-independent manner. These instructions cover the element-access and
3791 vector-specific operations needed to process vectors effectively. While LLVM
3792 does directly support these vector operations, many sophisticated algorithms
3793 will want to use target-specific intrinsics to take full advantage of a
3794 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3795
3796</div>
3797
3798<!-- _______________________________________________________________________ -->
3799<div class="doc_subsubsection">
3800 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3801</div>
3802
3803<div class="doc_text">
3804
3805<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3806<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3807 &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]3808</pre>
3809
3810<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3811<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3812 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3813
3814
3815<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3816<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3817 of <a href="#t_vector">vector</a> type. The second operand is an index
3818 indicating the position from which to extract the element. The index may be
3819 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3820
3821<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3822<p>The result is a scalar of the same type as the element type of
3823 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3824 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3825 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3826
3827<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3828<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3829 &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]3830</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3831
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3832</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3833
3834<!-- _______________________________________________________________________ -->
3835<div class="doc_subsubsection">
3836 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3837</div>
3838
3839<div class="doc_text">
3840
3841<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3842<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]3843 &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]3844</pre>
3845
3846<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3847<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3848 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3849
3850<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3851<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3852 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3853 whose type must equal the element type of the first operand. The third
3854 operand is an index indicating the position at which to insert the value.
3855 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3856
3857<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3858<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3859 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3860 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3861 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3862
3863<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3864<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3865 &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]3866</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3867
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3868</div>
3869
3870<!-- _______________________________________________________________________ -->
3871<div class="doc_subsubsection">
3872 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3873</div>
3874
3875<div class="doc_text">
3876
3877<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3878<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]3879 &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]3880</pre>
3881
3882<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3883<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3884 from two input vectors, returning a vector with the same element type as the
3885 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3886
3887<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3888<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3889 with types that match each other. The third argument is a shuffle mask whose
3890 element type is always 'i32'. The result of the instruction is a vector
3891 whose length is the same as the shuffle mask and whose element type is the
3892 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3893
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3894<p>The shuffle mask operand is required to be a constant vector with either
3895 constant integer or undef values.</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 elements of the two input vectors are numbered from left to right across
3899 both of the vectors. The shuffle mask operand specifies, for each element of
3900 the result vector, which element of the two input vectors the result element
3901 gets. The element selector may be undef (meaning "don't care") and the
3902 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3903
3904<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3905<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3906 &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]3907 &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]3908 &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]3909 &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]3910 &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]3911 &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]3912 &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]3913 &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]3914</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3915
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3916</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]3917
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3918<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3919<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3920 <a name="aggregateops">Aggregate Operations</a>
3921</div>
3922
3923<div class="doc_text">
3924
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3925<p>LLVM supports several instructions for working with
3926 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3927
3928</div>
3929
3930<!-- _______________________________________________________________________ -->
3931<div class="doc_subsubsection">
3932 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3933</div>
3934
3935<div class="doc_text">
3936
3937<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3938<pre>
3939 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3940</pre>
3941
3942<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3943<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
3944 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3945
3946<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3947<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3948 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
3949 <a href="#t_array">array</a> type. The operands are constant indices to
3950 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3951 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3952
3953<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3954<p>The result is the value at the position in the aggregate specified by the
3955 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3956
3957<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3958<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3959 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3960</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3961
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3962</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3963
3964<!-- _______________________________________________________________________ -->
3965<div class="doc_subsubsection">
3966 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3967</div>
3968
3969<div class="doc_text">
3970
3971<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3972<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]3973 &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]3974</pre>
3975
3976<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3977<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
3978 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3979
3980<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3981<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]3982 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
3983 <a href="#t_array">array</a> type. The second operand is a first-class
3984 value to insert. The following operands are constant indices indicating
3985 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]3986 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3987 value to insert must have the same type as the value identified by the
3988 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3989
3990<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3991<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3992 that of <tt>val</tt> except that the value at the position specified by the
3993 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3994
3995<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3996<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]3997 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
3998 %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]3999</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4000
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4001</div>
4002
4003
4004<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4005<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4006 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4007</div>
4008
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4009<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4010
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4011<p>A key design point of an SSA-based representation is how it represents
4012 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4013 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4014 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4015
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4016</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4017
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4018<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4019<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4020 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4021</div>
4022
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4023<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4024
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4025<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4026<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4027 &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]4028</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4029
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4030<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4031<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4032 currently executing function, to be automatically released when this function
4033 returns to its caller. The object is always allocated in the generic address
4034 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4035
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4036<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4037<p>The '<tt>alloca</tt>' instruction
4038 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4039 runtime stack, returning a pointer of the appropriate type to the program.
4040 If "NumElements" is specified, it is the number of elements allocated,
4041 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4042 specified, the value result of the allocation is guaranteed to be aligned to
4043 at least that boundary. If not specified, or if zero, the target can choose
4044 to align the allocation on any convenient boundary compatible with the
4045 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4046
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4047<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4048
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4049<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4050<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4051 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4052 memory is automatically released when the function returns. The
4053 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4054 variables that must have an address available. When the function returns
4055 (either with the <tt><a href="#i_ret">ret</a></tt>
4056 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4057 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4058
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4059<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4060<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4061 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4062 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4063 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4064 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4065</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4066
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4067</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4068
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4069<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4070<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4071Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4072
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4073<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4074
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4075<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4076<pre>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4077 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>]
4078 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>]
4079 !<index> = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4080</pre>
4081
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4082<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4083<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4084
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4085<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4086<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4087 from which to load. The pointer must point to
4088 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4089 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
4090 number or order of execution of this <tt>load</tt> with other
4091 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4092 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4093
4094<p>The optional constant "align" argument specifies the alignment of the
4095 operation (that is, the alignment of the memory address). A value of 0 or an
4096 omitted "align" argument means that the operation has the preferential
4097 alignment for the target. It is the responsibility of the code emitter to
4098 ensure that the alignment information is correct. Overestimating the
4099 alignment results in an undefined behavior. Underestimating the alignment may
4100 produce less efficient code. An alignment of 1 is always safe.</p>
4101
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4102<p>The optional !nontemporal metadata must reference a single metatadata
4103 name <index> corresponding to a metadata node with one i32 entry of
4104 value 1. The existance of the !nontemporal metatadata on the
4105 instruction tells the optimizer and code generator that this load is
4106 not expected to be reused in the cache. The code generator may
4107 select special instructions to save cache bandwidth, such as the
4108 MOVNT intruction on x86.</p>
4109
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4110<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4111<p>The location of memory pointed to is loaded. If the value being loaded is of
4112 scalar type then the number of bytes read does not exceed the minimum number
4113 of bytes needed to hold all bits of the type. For example, loading an
4114 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4115 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4116 is undefined if the value was not originally written using a store of the
4117 same type.</p>
4118
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4119<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4120<pre>
4121 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4122 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4123 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4124</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4125
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4126</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4127
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4128<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4129<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4130Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4131
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4132<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4133
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4134<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4135<pre>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4136 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4137 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]4138</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4139
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4140<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4141<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4142
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4143<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4144<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4145 and an address at which to store it. The type of the
4146 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4147 the <a href="#t_firstclass">first class</a> type of the
4148 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4149 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4150 or order of execution of this <tt>store</tt> with other
4151 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4152 instructions.</p>
4153
4154<p>The optional constant "align" argument specifies the alignment of the
4155 operation (that is, the alignment of the memory address). A value of 0 or an
4156 omitted "align" argument means that the operation has the preferential
4157 alignment for the target. It is the responsibility of the code emitter to
4158 ensure that the alignment information is correct. Overestimating the
4159 alignment results in an undefined behavior. Underestimating the alignment may
4160 produce less efficient code. An alignment of 1 is always safe.</p>
4161
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4162<p>The optional !nontemporal metadata must reference a single metatadata
4163 name <index> corresponding to a metadata node with one i32 entry of
4164 value 1. The existance of the !nontemporal metatadata on the
4165 instruction tells the optimizer and code generator that this load is
4166 not expected to be reused in the cache. The code generator may
4167 select special instructions to save cache bandwidth, such as the
4168 MOVNT intruction on x86.</p>
4169
4170
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4171<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4172<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4173 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4174 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4175 does not exceed the minimum number of bytes needed to hold all bits of the
4176 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4177 writing a value of a type like <tt>i20</tt> with a size that is not an
4178 integral number of bytes, it is unspecified what happens to the extra bits
4179 that do not belong to the type, but they will typically be overwritten.</p>
4180
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4181<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4182<pre>
4183 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4184 store i32 3, i32* %ptr <i>; yields {void}</i>
4185 %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]4186</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4187
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4188</div>
4189
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4190<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4191<div class="doc_subsubsection">
4192 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4193</div>
4194
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4195<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4196
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4197<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4198<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4199 &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]4200 &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]4201</pre>
4202
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4203<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4204<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4205 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4206 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4207
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4208<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4209<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4210 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4211 elements of the aggregate object are indexed. The interpretation of each
4212 index is dependent on the type being indexed into. The first index always
4213 indexes the pointer value given as the first argument, the second index
4214 indexes a value of the type pointed to (not necessarily the value directly
4215 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4216 indexed into must be a pointer value, subsequent types can be arrays,
4217 vectors, structs and unions. Note that subsequent types being indexed into
4218 can never be pointers, since that would require loading the pointer before
4219 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4220
4221<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]4222 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4223 integer <b>constants</b> are allowed. When indexing into an array, pointer
4224 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]4225 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4226
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4227<p>For example, let's consider a C code fragment and how it gets compiled to
4228 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4229
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4230<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4231<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4232struct RT {
4233 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4234 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4235 char C;
4236};
4237struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4238 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4239 double Y;
4240 struct RT Z;
4241};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4242
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4243int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4244 return &amp;s[1].Z.B[5][13];
4245}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4246</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4247</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4248
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4249<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4250
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4251<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4252<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4253%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4254%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4255
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4256define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4257entry:
4258 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4259 ret i32* %reg
4260}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4261</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4262</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4263
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4264<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4265<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]4266 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4267 }</tt>' type, a structure. The second index indexes into the third element
4268 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4269 i8 }</tt>' type, another structure. The third index indexes into the second
4270 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4271 array. The two dimensions of the array are subscripted into, yielding an
4272 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4273 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4274
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4275<p>Note that it is perfectly legal to index partially through a structure,
4276 returning a pointer to an inner element. Because of this, the LLVM code for
4277 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4278
4279<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4280 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4281 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4282 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4283 %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]4284 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4285 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4286 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4287 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4288</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4289
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4290<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4291 <tt>getelementptr</tt> is undefined if the base pointer is not an
4292 <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]4293 that would be formed by successive addition of the offsets implied by the
4294 indices to the base address with infinitely precise arithmetic are not an
4295 <i>in bounds</i> address of that allocated object.
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4296 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohman2de532c2009-08-20 17:08:17 +0000[diff] [blame]4297 that point into the object, plus the address one byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4298
4299<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4300 the base address with silently-wrapping two's complement arithmetic, and
4301 the result value of the <tt>getelementptr</tt> may be outside the object
4302 pointed to by the base pointer. The result value may not necessarily be
4303 used to access memory though, even if it happens to point into allocated
4304 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4305 section for more information.</p>
4306
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4307<p>The getelementptr instruction is often confusing. For some more insight into
4308 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4309
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4310<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4311<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4312 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4313 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4314 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4315 %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]4316 <i>; yields i8*:eptr</i>
4317 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4318 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4319 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4320</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4321
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4322</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4323
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4324<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4325<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4326</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4327
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4328<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4329
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4330<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4331 which all take a single operand and a type. They perform various bit
4332 conversions on the operand.</p>
4333
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4334</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4335
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4336<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4337<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4338 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4339</div>
4340<div class="doc_text">
4341
4342<h5>Syntax:</h5>
4343<pre>
4344 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4345</pre>
4346
4347<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4348<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4349 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4350
4351<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4352<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4353 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4354 size and type of the result, which must be
4355 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4356 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4357 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4358
4359<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4360<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4361 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4362 source size must be larger than the destination size, <tt>trunc</tt> cannot
4363 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4364
4365<h5>Example:</h5>
4366<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4367 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4368 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4369 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4370</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4371
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4372</div>
4373
4374<!-- _______________________________________________________________________ -->
4375<div class="doc_subsubsection">
4376 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4377</div>
4378<div class="doc_text">
4379
4380<h5>Syntax:</h5>
4381<pre>
4382 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4383</pre>
4384
4385<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4386<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4387 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4388
4389
4390<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4391<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]4392 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4393 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]4394 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4395 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4396
4397<h5>Semantics:</h5>
4398<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]4399 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4400
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4401<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]4402
4403<h5>Example:</h5>
4404<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4405 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4406 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4407</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4408
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4409</div>
4410
4411<!-- _______________________________________________________________________ -->
4412<div class="doc_subsubsection">
4413 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4414</div>
4415<div class="doc_text">
4416
4417<h5>Syntax:</h5>
4418<pre>
4419 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4420</pre>
4421
4422<h5>Overview:</h5>
4423<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4424
4425<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4426<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]4427 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4428 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]4429 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4430 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4431
4432<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4433<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4434 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4435 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4436
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4437<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]4438
4439<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4440<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4441 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4442 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4443</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4444
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4445</div>
4446
4447<!-- _______________________________________________________________________ -->
4448<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4449 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4450</div>
4451
4452<div class="doc_text">
4453
4454<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4455<pre>
4456 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4457</pre>
4458
4459<h5>Overview:</h5>
4460<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4461 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4462
4463<h5>Arguments:</h5>
4464<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4465 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4466 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]4467 <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]4468 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4469
4470<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4471<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4472 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4473 <a href="#t_floating">floating point</a> type. If the value cannot fit
4474 within the destination type, <tt>ty2</tt>, then the results are
4475 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4476
4477<h5>Example:</h5>
4478<pre>
4479 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4480 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4481</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4482
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4483</div>
4484
4485<!-- _______________________________________________________________________ -->
4486<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4487 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4488</div>
4489<div class="doc_text">
4490
4491<h5>Syntax:</h5>
4492<pre>
4493 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4494</pre>
4495
4496<h5>Overview:</h5>
4497<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]4498 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4499
4500<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4501<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4502 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4503 a <a href="#t_floating">floating point</a> type to cast it to. The source
4504 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4505
4506<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4507<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4508 <a href="#t_floating">floating point</a> type to a larger
4509 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4510 used to make a <i>no-op cast</i> because it always changes bits. Use
4511 <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]4512
4513<h5>Example:</h5>
4514<pre>
4515 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4516 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4517</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4518
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4519</div>
4520
4521<!-- _______________________________________________________________________ -->
4522<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4523 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4524</div>
4525<div class="doc_text">
4526
4527<h5>Syntax:</h5>
4528<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4529 &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]4530</pre>
4531
4532<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4533<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4534 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4535
4536<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4537<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4538 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4539 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4540 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4541 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4542
4543<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4544<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4545 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4546 towards zero) unsigned integer value. If the value cannot fit
4547 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4548
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4549<h5>Example:</h5>
4550<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4551 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4552 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4553 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4554</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4555
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4556</div>
4557
4558<!-- _______________________________________________________________________ -->
4559<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4560 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4561</div>
4562<div class="doc_text">
4563
4564<h5>Syntax:</h5>
4565<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4566 &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]4567</pre>
4568
4569<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4570<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4571 <a href="#t_floating">floating point</a> <tt>value</tt> to
4572 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4573
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4574<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4575<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4576 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4577 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4578 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4579 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4580
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4581<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4582<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4583 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4584 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4585 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4586
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4587<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4588<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4589 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4590 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4591 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4592</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4593
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4594</div>
4595
4596<!-- _______________________________________________________________________ -->
4597<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4598 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4599</div>
4600<div class="doc_text">
4601
4602<h5>Syntax:</h5>
4603<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4604 &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]4605</pre>
4606
4607<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4608<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4609 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4610
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4611<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4612<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]4613 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4614 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4615 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4616 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4617
4618<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4619<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4620 integer quantity and converts it to the corresponding floating point
4621 value. If the value cannot fit in the floating point value, the results are
4622 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4623
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4624<h5>Example:</h5>
4625<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4626 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4627 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4628</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4629
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4630</div>
4631
4632<!-- _______________________________________________________________________ -->
4633<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4634 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4635</div>
4636<div class="doc_text">
4637
4638<h5>Syntax:</h5>
4639<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4640 &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]4641</pre>
4642
4643<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4644<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4645 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4646
4647<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4648<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]4649 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4650 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4651 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4652 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4653
4654<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4655<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4656 quantity and converts it to the corresponding floating point value. If the
4657 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4658
4659<h5>Example:</h5>
4660<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4661 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4662 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4663</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4664
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4665</div>
4666
4667<!-- _______________________________________________________________________ -->
4668<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4669 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4670</div>
4671<div class="doc_text">
4672
4673<h5>Syntax:</h5>
4674<pre>
4675 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4676</pre>
4677
4678<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4679<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4680 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4681
4682<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4683<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4684 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4685 <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]4686
4687<h5>Semantics:</h5>
4688<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4689 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4690 truncating or zero extending that value to the size of the integer type. If
4691 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4692 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4693 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4694 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4695
4696<h5>Example:</h5>
4697<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4698 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4699 %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]4700</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4701
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4702</div>
4703
4704<!-- _______________________________________________________________________ -->
4705<div class="doc_subsubsection">
4706 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4707</div>
4708<div class="doc_text">
4709
4710<h5>Syntax:</h5>
4711<pre>
4712 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4713</pre>
4714
4715<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4716<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4717 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4718
4719<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4720<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4721 value to cast, and a type to cast it to, which must be a
4722 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4723
4724<h5>Semantics:</h5>
4725<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4726 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4727 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4728 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4729 than the size of a pointer then a zero extension is done. If they are the
4730 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4731
4732<h5>Example:</h5>
4733<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4734 %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]4735 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4736 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4737</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4738
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4739</div>
4740
4741<!-- _______________________________________________________________________ -->
4742<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4743 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4744</div>
4745<div class="doc_text">
4746
4747<h5>Syntax:</h5>
4748<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4749 &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]4750</pre>
4751
4752<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4753<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4754 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4755
4756<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4757<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4758 non-aggregate first class value, and a type to cast it to, which must also be
4759 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4760 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4761 identical. If the source type is a pointer, the destination type must also be
4762 a pointer. This instruction supports bitwise conversion of vectors to
4763 integers and to vectors of other types (as long as they have the same
4764 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4765
4766<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4767<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4768 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4769 this conversion. The conversion is done as if the <tt>value</tt> had been
4770 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4771 be converted to other pointer types with this instruction. To convert
4772 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4773 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4774
4775<h5>Example:</h5>
4776<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4777 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4778 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4779 %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]4780</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4781
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4782</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4783
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4784<!-- ======================================================================= -->
4785<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4786
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4787<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4788
4789<p>The instructions in this category are the "miscellaneous" instructions, which
4790 defy better classification.</p>
4791
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4792</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4793
4794<!-- _______________________________________________________________________ -->
4795<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4796</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4797
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4798<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4799
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4800<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4801<pre>
4802 &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]4803</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4804
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4805<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4806<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4807 boolean values based on comparison of its two integer, integer vector, or
4808 pointer operands.</p>
4809
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4810<h5>Arguments:</h5>
4811<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4812 the condition code indicating the kind of comparison to perform. It is not a
4813 value, just a keyword. The possible condition code are:</p>
4814
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4815<ol>
4816 <li><tt>eq</tt>: equal</li>
4817 <li><tt>ne</tt>: not equal </li>
4818 <li><tt>ugt</tt>: unsigned greater than</li>
4819 <li><tt>uge</tt>: unsigned greater or equal</li>
4820 <li><tt>ult</tt>: unsigned less than</li>
4821 <li><tt>ule</tt>: unsigned less or equal</li>
4822 <li><tt>sgt</tt>: signed greater than</li>
4823 <li><tt>sge</tt>: signed greater or equal</li>
4824 <li><tt>slt</tt>: signed less than</li>
4825 <li><tt>sle</tt>: signed less or equal</li>
4826</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4827
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]4828<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4829 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4830 typed. They must also be identical types.</p>
4831
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4832<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4833<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4834 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4835 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]4836 result, as follows:</p>
4837
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4838<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4839 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4840 <tt>false</tt> otherwise. No sign interpretation is necessary or
4841 performed.</li>
4842
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4843 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4844 <tt>false</tt> otherwise. No sign interpretation is necessary or
4845 performed.</li>
4846
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4847 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4848 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4849
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4850 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4851 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4852 to <tt>op2</tt>.</li>
4853
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4854 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4855 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4856
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4857 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4858 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4859
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4860 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4861 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4862
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4863 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4864 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4865 to <tt>op2</tt>.</li>
4866
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4867 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4868 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4869
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4870 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4871 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4872</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4873
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4874<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4875 values are compared as if they were integers.</p>
4876
4877<p>If the operands are integer vectors, then they are compared element by
4878 element. The result is an <tt>i1</tt> vector with the same number of elements
4879 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4880
4881<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4882<pre>
4883 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4884 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4885 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4886 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4887 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4888 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4889</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4890
4891<p>Note that the code generator does not yet support vector types with
4892 the <tt>icmp</tt> instruction.</p>
4893
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4894</div>
4895
4896<!-- _______________________________________________________________________ -->
4897<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4898</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4899
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4900<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4901
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4902<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4903<pre>
4904 &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]4905</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4906
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4907<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4908<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4909 values based on comparison of its operands.</p>
4910
4911<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]4912(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4913
4914<p>If the operands are floating point vectors, then the result type is a vector
4915 of boolean with the same number of elements as the operands being
4916 compared.</p>
4917
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4918<h5>Arguments:</h5>
4919<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4920 the condition code indicating the kind of comparison to perform. It is not a
4921 value, just a keyword. The possible condition code are:</p>
4922
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4923<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4924 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4925 <li><tt>oeq</tt>: ordered and equal</li>
4926 <li><tt>ogt</tt>: ordered and greater than </li>
4927 <li><tt>oge</tt>: ordered and greater than or equal</li>
4928 <li><tt>olt</tt>: ordered and less than </li>
4929 <li><tt>ole</tt>: ordered and less than or equal</li>
4930 <li><tt>one</tt>: ordered and not equal</li>
4931 <li><tt>ord</tt>: ordered (no nans)</li>
4932 <li><tt>ueq</tt>: unordered or equal</li>
4933 <li><tt>ugt</tt>: unordered or greater than </li>
4934 <li><tt>uge</tt>: unordered or greater than or equal</li>
4935 <li><tt>ult</tt>: unordered or less than </li>
4936 <li><tt>ule</tt>: unordered or less than or equal</li>
4937 <li><tt>une</tt>: unordered or not equal</li>
4938 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4939 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4940</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4941
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4942<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4943 <i>unordered</i> means that either operand may be a QNAN.</p>
4944
4945<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4946 a <a href="#t_floating">floating point</a> type or
4947 a <a href="#t_vector">vector</a> of floating point type. They must have
4948 identical types.</p>
4949
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4950<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4951<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4952 according to the condition code given as <tt>cond</tt>. If the operands are
4953 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4954 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4955 follows:</p>
4956
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4957<ol>
4958 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4959
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4960 <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]4961 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4962
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4963 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4964 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4965
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4966 <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]4967 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4968
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4969 <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]4970 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4971
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4972 <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]4973 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4974
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4975 <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]4976 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4977
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4978 <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]4979
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4980 <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]4981 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4982
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4983 <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]4984 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4985
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4986 <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]4987 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4988
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4989 <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]4990 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4991
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4992 <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]4993 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4994
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4995 <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]4996 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4997
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4998 <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]4999
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5000 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5001</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5002
5003<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5004<pre>
5005 &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]5006 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5007 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5008 &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]5009</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5010
5011<p>Note that the code generator does not yet support vector types with
5012 the <tt>fcmp</tt> instruction.</p>
5013
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5014</div>
5015
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5016<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5017<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5018 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5019</div>
5020
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5021<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5022
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5023<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5024<pre>
5025 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5026</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5027
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5028<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5029<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5030 SSA graph representing the function.</p>
5031
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5032<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5033<p>The type of the incoming values is specified with the first type field. After
5034 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5035 one pair for each predecessor basic block of the current block. Only values
5036 of <a href="#t_firstclass">first class</a> type may be used as the value
5037 arguments to the PHI node. Only labels may be used as the label
5038 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5039
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5040<p>There must be no non-phi instructions between the start of a basic block and
5041 the PHI instructions: i.e. PHI instructions must be first in a basic
5042 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5043
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5044<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5045 occur on the edge from the corresponding predecessor block to the current
5046 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5047 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5048
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5049<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5050<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5051 specified by the pair corresponding to the predecessor basic block that
5052 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5053
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5054<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5055<pre>
5056Loop: ; Infinite loop that counts from 0 on up...
5057 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5058 %nextindvar = add i32 %indvar, 1
5059 br label %Loop
5060</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5061
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5062</div>
5063
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5064<!-- _______________________________________________________________________ -->
5065<div class="doc_subsubsection">
5066 <a name="i_select">'<tt>select</tt>' Instruction</a>
5067</div>
5068
5069<div class="doc_text">
5070
5071<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5072<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5073 &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>
5074
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5075 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5076</pre>
5077
5078<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5079<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5080 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5081
5082
5083<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5084<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5085 values indicating the condition, and two values of the
5086 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5087 vectors and the condition is a scalar, then entire vectors are selected, not
5088 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5089
5090<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5091<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5092 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5093
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5094<p>If the condition is a vector of i1, then the value arguments must be vectors
5095 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5096
5097<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5098<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5099 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5100</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5101
5102<p>Note that the code generator does not yet support conditions
5103 with vector type.</p>
5104
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5105</div>
5106
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5107<!-- _______________________________________________________________________ -->
5108<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5109 <a name="i_call">'<tt>call</tt>' Instruction</a>
5110</div>
5111
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5112<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5113
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5114<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5115<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5116 &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]5117</pre>
5118
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5119<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5120<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5121
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5122<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5123<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5124
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5125<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5126 <li>The optional "tail" marker indicates that the callee function does not
5127 access any allocas or varargs in the caller. Note that calls may be
5128 marked "tail" even if they do not occur before
5129 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5130 present, the function call is eligible for tail call optimization,
5131 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
5132 optimized into a jump</a>. As of this writing, the extra requirements for
5133 a call to actually be optimized are:
5134 <ul>
5135 <li>Caller and callee both have the calling
5136 convention <tt>fastcc</tt>.</li>
5137 <li>The call is in tail position (ret immediately follows call and ret
5138 uses value of call or is void).</li>
5139 <li>Option <tt>-tailcallopt</tt> is enabled,
5140 or <code>llvm::PerformTailCallOpt</code> is <code>true</code>.</li>
5141 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5142 constraints are met.</a></li>
5143 </ul>
5144 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5145
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5146 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5147 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5148 defaults to using C calling conventions. The calling convention of the
5149 call must match the calling convention of the target function, or else the
5150 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5151
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5152 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5153 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5154 '<tt>inreg</tt>' attributes are valid here.</li>
5155
5156 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5157 type of the return value. Functions that return no value are marked
5158 <tt><a href="#t_void">void</a></tt>.</li>
5159
5160 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5161 being invoked. The argument types must match the types implied by this
5162 signature. This type can be omitted if the function is not varargs and if
5163 the function type does not return a pointer to a function.</li>
5164
5165 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5166 be invoked. In most cases, this is a direct function invocation, but
5167 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5168 to function value.</li>
5169
5170 <li>'<tt>function args</tt>': argument list whose types match the function
5171 signature argument types. All arguments must be of
5172 <a href="#t_firstclass">first class</a> type. If the function signature
5173 indicates the function accepts a variable number of arguments, the extra
5174 arguments can be specified.</li>
5175
5176 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5177 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5178 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5179</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5180
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5181<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5182<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5183 a specified function, with its incoming arguments bound to the specified
5184 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5185 function, control flow continues with the instruction after the function
5186 call, and the return value of the function is bound to the result
5187 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5188
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5189<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5190<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5191 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5192 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5193 %X = tail call i32 @foo() <i>; yields i32</i>
5194 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5195 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5196
5197 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5198 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5199 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5200 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5201 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5202 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5203</pre>
5204
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5205<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5206standard C99 library as being the C99 library functions, and may perform
5207optimizations or generate code for them under that assumption. This is
5208something we'd like to change in the future to provide better support for
5209freestanding environments and non-C-based langauges.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5210
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5211</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5212
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5213<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5214<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5215 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5216</div>
5217
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5218<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5219
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5220<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5221<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5222 &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]5223</pre>
5224
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5225<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5226<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5227 the "variable argument" area of a function call. It is used to implement the
5228 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5229
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5230<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5231<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5232 argument. It returns a value of the specified argument type and increments
5233 the <tt>va_list</tt> to point to the next argument. The actual type
5234 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5235
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5236<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5237<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5238 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5239 to the next argument. For more information, see the variable argument
5240 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5241
5242<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]5243 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5244 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5245
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5246<p><tt>va_arg</tt> is an LLVM instruction instead of
5247 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5248 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5249
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5250<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5251<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5252
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5253<p>Note that the code generator does not yet fully support va_arg on many
5254 targets. Also, it does not currently support va_arg with aggregate types on
5255 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5256
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5257</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5258
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5259<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5260<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5261<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5262
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5263<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5264
5265<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5266 well known names and semantics and are required to follow certain
5267 restrictions. Overall, these intrinsics represent an extension mechanism for
5268 the LLVM language that does not require changing all of the transformations
5269 in LLVM when adding to the language (or the bitcode reader/writer, the
5270 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5271
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5272<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5273 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5274 begin with this prefix. Intrinsic functions must always be external
5275 functions: you cannot define the body of intrinsic functions. Intrinsic
5276 functions may only be used in call or invoke instructions: it is illegal to
5277 take the address of an intrinsic function. Additionally, because intrinsic
5278 functions are part of the LLVM language, it is required if any are added that
5279 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5280
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5281<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5282 family of functions that perform the same operation but on different data
5283 types. Because LLVM can represent over 8 million different integer types,
5284 overloading is used commonly to allow an intrinsic function to operate on any
5285 integer type. One or more of the argument types or the result type can be
5286 overloaded to accept any integer type. Argument types may also be defined as
5287 exactly matching a previous argument's type or the result type. This allows
5288 an intrinsic function which accepts multiple arguments, but needs all of them
5289 to be of the same type, to only be overloaded with respect to a single
5290 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5291
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5292<p>Overloaded intrinsics will have the names of its overloaded argument types
5293 encoded into its function name, each preceded by a period. Only those types
5294 which are overloaded result in a name suffix. Arguments whose type is matched
5295 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5296 can take an integer of any width and returns an integer of exactly the same
5297 integer width. This leads to a family of functions such as
5298 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5299 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5300 suffix is required. Because the argument's type is matched against the return
5301 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5302
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5303<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5304 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5305
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5306</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5307
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5308<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5309<div class="doc_subsection">
5310 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5311</div>
5312
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5313<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5314
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5315<p>Variable argument support is defined in LLVM with
5316 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5317 intrinsic functions. These functions are related to the similarly named
5318 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5319
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5320<p>All of these functions operate on arguments that use a target-specific value
5321 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5322 not define what this type is, so all transformations should be prepared to
5323 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5324
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5325<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]5326 instruction and the variable argument handling intrinsic functions are
5327 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5328
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5329<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5330<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5331define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5332 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5333 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5334 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5335 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5336
5337 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5338 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5339
5340 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5341 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5342 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5343 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5344 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5345
5346 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5347 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5348 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5349}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5350
5351declare void @llvm.va_start(i8*)
5352declare void @llvm.va_copy(i8*, i8*)
5353declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5354</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5355</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5356
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5357</div>
5358
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5359<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5360<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5361 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5362</div>
5363
5364
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5365<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5366
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5367<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5368<pre>
5369 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5370</pre>
5371
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5372<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5373<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5374 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]5375
5376<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5377<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]5378
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5379<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5380<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]5381 macro available in C. In a target-dependent way, it initializes
5382 the <tt>va_list</tt> element to which the argument points, so that the next
5383 call to <tt>va_arg</tt> will produce the first variable argument passed to
5384 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5385 need to know the last argument of the function as the compiler can figure
5386 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5387
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5388</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5389
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5390<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5391<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5392 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5393</div>
5394
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5395<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5396
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5397<h5>Syntax:</h5>
5398<pre>
5399 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5400</pre>
5401
5402<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5403<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5404 which has been initialized previously
5405 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5406 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5407
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5408<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5409<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]5410
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5411<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5412<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]5413 macro available in C. In a target-dependent way, it destroys
5414 the <tt>va_list</tt> element to which the argument points. Calls
5415 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5416 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5417 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5418
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5419</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5420
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5421<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5422<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5423 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5424</div>
5425
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5426<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5427
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5428<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5429<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5430 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5431</pre>
5432
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5433<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5434<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5435 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5436
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5437<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5438<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]5439 The second argument is a pointer to a <tt>va_list</tt> element to copy
5440 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5441
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5442<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5443<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]5444 macro available in C. In a target-dependent way, it copies the
5445 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5446 element. This intrinsic is necessary because
5447 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5448 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5449
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5450</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5451
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5452<!-- ======================================================================= -->
5453<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5454 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5455</div>
5456
5457<div class="doc_text">
5458
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5459<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5460Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5461intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5462roots on the stack</a>, as well as garbage collector implementations that
5463require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5464barriers. Front-ends for type-safe garbage collected languages should generate
5465these intrinsics to make use of the LLVM garbage collectors. For more details,
5466see <a href="GarbageCollection.html">Accurate Garbage Collection with
5467LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5468
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5469<p>The garbage collection intrinsics only operate on objects in the generic
5470 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5471
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5472</div>
5473
5474<!-- _______________________________________________________________________ -->
5475<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5476 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5477</div>
5478
5479<div class="doc_text">
5480
5481<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5482<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5483 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5484</pre>
5485
5486<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5487<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]5488 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5489
5490<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5491<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5492 root pointer. The second pointer (which must be either a constant or a
5493 global value address) contains the meta-data to be associated with the
5494 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5495
5496<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5497<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]5498 location. At compile-time, the code generator generates information to allow
5499 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5500 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5501 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5502
5503</div>
5504
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5505<!-- _______________________________________________________________________ -->
5506<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5507 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5508</div>
5509
5510<div class="doc_text">
5511
5512<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5513<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5514 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5515</pre>
5516
5517<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5518<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5519 locations, allowing garbage collector implementations that require read
5520 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5521
5522<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5523<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]5524 allocated from the garbage collector. The first object is a pointer to the
5525 start of the referenced object, if needed by the language runtime (otherwise
5526 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5527
5528<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5529<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5530 instruction, but may be replaced with substantially more complex code by the
5531 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5532 may only be used in a function which <a href="#gc">specifies a GC
5533 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5534
5535</div>
5536
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5537<!-- _______________________________________________________________________ -->
5538<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5539 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5540</div>
5541
5542<div class="doc_text">
5543
5544<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5545<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5546 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5547</pre>
5548
5549<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5550<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5551 locations, allowing garbage collector implementations that require write
5552 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5553
5554<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5555<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]5556 object to store it to, and the third is the address of the field of Obj to
5557 store to. If the runtime does not require a pointer to the object, Obj may
5558 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5559
5560<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5561<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5562 instruction, but may be replaced with substantially more complex code by the
5563 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5564 may only be used in a function which <a href="#gc">specifies a GC
5565 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5566
5567</div>
5568
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5569<!-- ======================================================================= -->
5570<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5571 <a name="int_codegen">Code Generator Intrinsics</a>
5572</div>
5573
5574<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5575
5576<p>These intrinsics are provided by LLVM to expose special features that may
5577 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5578
5579</div>
5580
5581<!-- _______________________________________________________________________ -->
5582<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5583 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5584</div>
5585
5586<div class="doc_text">
5587
5588<h5>Syntax:</h5>
5589<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5590 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5591</pre>
5592
5593<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5594<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5595 target-specific value indicating the return address of the current function
5596 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5597
5598<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5599<p>The argument to this intrinsic indicates which function to return the address
5600 for. Zero indicates the calling function, one indicates its caller, etc.
5601 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5602
5603<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5604<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5605 indicating the return address of the specified call frame, or zero if it
5606 cannot be identified. The value returned by this intrinsic is likely to be
5607 incorrect or 0 for arguments other than zero, so it should only be used for
5608 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5609
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5610<p>Note that calling this intrinsic does not prevent function inlining or other
5611 aggressive transformations, so the value returned may not be that of the
5612 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5613
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5614</div>
5615
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5616<!-- _______________________________________________________________________ -->
5617<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5618 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5619</div>
5620
5621<div class="doc_text">
5622
5623<h5>Syntax:</h5>
5624<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5625 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5626</pre>
5627
5628<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5629<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5630 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5631
5632<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5633<p>The argument to this intrinsic indicates which function to return the frame
5634 pointer for. Zero indicates the calling function, one indicates its caller,
5635 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5636
5637<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5638<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5639 indicating the frame address of the specified call frame, or zero if it
5640 cannot be identified. The value returned by this intrinsic is likely to be
5641 incorrect or 0 for arguments other than zero, so it should only be used for
5642 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5643
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5644<p>Note that calling this intrinsic does not prevent function inlining or other
5645 aggressive transformations, so the value returned may not be that of the
5646 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5647
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5648</div>
5649
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5650<!-- _______________________________________________________________________ -->
5651<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5652 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5653</div>
5654
5655<div class="doc_text">
5656
5657<h5>Syntax:</h5>
5658<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5659 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5660</pre>
5661
5662<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5663<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5664 of the function stack, for use
5665 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5666 useful for implementing language features like scoped automatic variable
5667 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5668
5669<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5670<p>This intrinsic returns a opaque pointer value that can be passed
5671 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5672 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5673 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5674 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5675 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5676 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5677
5678</div>
5679
5680<!-- _______________________________________________________________________ -->
5681<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5682 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5683</div>
5684
5685<div class="doc_text">
5686
5687<h5>Syntax:</h5>
5688<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5689 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5690</pre>
5691
5692<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5693<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5694 the function stack to the state it was in when the
5695 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5696 executed. This is useful for implementing language features like scoped
5697 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5698
5699<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5700<p>See the description
5701 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5702
5703</div>
5704
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5705<!-- _______________________________________________________________________ -->
5706<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5707 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5708</div>
5709
5710<div class="doc_text">
5711
5712<h5>Syntax:</h5>
5713<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5714 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]5715</pre>
5716
5717<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5718<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5719 insert a prefetch instruction if supported; otherwise, it is a noop.
5720 Prefetches have no effect on the behavior of the program but can change its
5721 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5722
5723<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5724<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5725 specifier determining if the fetch should be for a read (0) or write (1),
5726 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5727 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5728 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5729
5730<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5731<p>This intrinsic does not modify the behavior of the program. In particular,
5732 prefetches cannot trap and do not produce a value. On targets that support
5733 this intrinsic, the prefetch can provide hints to the processor cache for
5734 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5735
5736</div>
5737
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5738<!-- _______________________________________________________________________ -->
5739<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5740 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5741</div>
5742
5743<div class="doc_text">
5744
5745<h5>Syntax:</h5>
5746<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5747 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5748</pre>
5749
5750<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5751<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5752 Counter (PC) in a region of code to simulators and other tools. The method
5753 is target specific, but it is expected that the marker will use exported
5754 symbols to transmit the PC of the marker. The marker makes no guarantees
5755 that it will remain with any specific instruction after optimizations. It is
5756 possible that the presence of a marker will inhibit optimizations. The
5757 intended use is to be inserted after optimizations to allow correlations of
5758 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5759
5760<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5761<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5762
5763<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5764<p>This intrinsic does not modify the behavior of the program. Backends that do
5765 not support this intrinisic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5766
5767</div>
5768
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5769<!-- _______________________________________________________________________ -->
5770<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5771 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5772</div>
5773
5774<div class="doc_text">
5775
5776<h5>Syntax:</h5>
5777<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5778 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5779</pre>
5780
5781<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5782<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5783 counter register (or similar low latency, high accuracy clocks) on those
5784 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5785 should map to RPCC. As the backing counters overflow quickly (on the order
5786 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5787
5788<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5789<p>When directly supported, reading the cycle counter should not modify any
5790 memory. Implementations are allowed to either return a application specific
5791 value or a system wide value. On backends without support, this is lowered
5792 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5793
5794</div>
5795
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5796<!-- ======================================================================= -->
5797<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5798 <a name="int_libc">Standard C Library Intrinsics</a>
5799</div>
5800
5801<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5802
5803<p>LLVM provides intrinsics for a few important standard C library functions.
5804 These intrinsics allow source-language front-ends to pass information about
5805 the alignment of the pointer arguments to the code generator, providing
5806 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5807
5808</div>
5809
5810<!-- _______________________________________________________________________ -->
5811<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5812 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5813</div>
5814
5815<div class="doc_text">
5816
5817<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5818<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5819 integer bit width. Not all targets support all bit widths however.</p>
5820
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5821<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5822 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5823 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5824 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5825 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5826 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5827 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5828 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5829 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5830</pre>
5831
5832<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5833<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5834 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5835
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5836<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5837 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5838
5839<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5840<p>The first argument is a pointer to the destination, the second is a pointer
5841 to the source. The third argument is an integer argument specifying the
5842 number of bytes to copy, and the fourth argument is the alignment of the
5843 source and destination locations.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5844
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5845<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5846 then the caller guarantees that both the source and destination pointers are
5847 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5848
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5849<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5850<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5851 source location to the destination location, which are not allowed to
5852 overlap. It copies "len" bytes of memory over. If the argument is known to
5853 be aligned to some boundary, this can be specified as the fourth argument,
5854 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5855
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5856</div>
5857
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5858<!-- _______________________________________________________________________ -->
5859<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5860 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5861</div>
5862
5863<div class="doc_text">
5864
5865<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5866<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]5867 width. Not all targets support all bit widths however.</p>
5868
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5869<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5870 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5871 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5872 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5873 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5874 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5875 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5876 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5877 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5878</pre>
5879
5880<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5881<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5882 source location to the destination location. It is similar to the
5883 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5884 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5885
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5886<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5887 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5888
5889<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5890<p>The first argument is a pointer to the destination, the second is a pointer
5891 to the source. The third argument is an integer argument specifying the
5892 number of bytes to copy, and the fourth argument is the alignment of the
5893 source and destination locations.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5894
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5895<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5896 then the caller guarantees that the source and destination pointers are
5897 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5898
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5899<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5900<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5901 source location to the destination location, which may overlap. It copies
5902 "len" bytes of memory over. If the argument is known to be aligned to some
5903 boundary, this can be specified as the fourth argument, otherwise it should
5904 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5905
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5906</div>
5907
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5908<!-- _______________________________________________________________________ -->
5909<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5910 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5911</div>
5912
5913<div class="doc_text">
5914
5915<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5916<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]5917 width. Not all targets support all bit widths however.</p>
5918
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5919<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5920 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5921 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5922 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5923 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5924 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5925 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5926 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5927 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5928</pre>
5929
5930<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5931<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5932 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5933
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5934<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5935 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5936
5937<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5938<p>The first argument is a pointer to the destination to fill, the second is the
5939 byte value to fill it with, the third argument is an integer argument
5940 specifying the number of bytes to fill, and the fourth argument is the known
5941 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5942
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5943<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5944 then the caller guarantees that the destination pointer is aligned to that
5945 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5946
5947<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5948<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5949 at the destination location. If the argument is known to be aligned to some
5950 boundary, this can be specified as the fourth argument, otherwise it should
5951 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5952
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5953</div>
5954
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5955<!-- _______________________________________________________________________ -->
5956<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5957 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5958</div>
5959
5960<div class="doc_text">
5961
5962<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5963<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5964 floating point or vector of floating point type. Not all targets support all
5965 types however.</p>
5966
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5967<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5968 declare float @llvm.sqrt.f32(float %Val)
5969 declare double @llvm.sqrt.f64(double %Val)
5970 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5971 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5972 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5973</pre>
5974
5975<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5976<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5977 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5978 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5979 behavior for negative numbers other than -0.0 (which allows for better
5980 optimization, because there is no need to worry about errno being
5981 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]5982
5983<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5984<p>The argument and return value are floating point numbers of the same
5985 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5986
5987<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5988<p>This function returns the sqrt of the specified operand if it is a
5989 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5990
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5991</div>
5992
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5993<!-- _______________________________________________________________________ -->
5994<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5995 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5996</div>
5997
5998<div class="doc_text">
5999
6000<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6001<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6002 floating point or vector of floating point type. Not all targets support all
6003 types however.</p>
6004
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6005<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6006 declare float @llvm.powi.f32(float %Val, i32 %power)
6007 declare double @llvm.powi.f64(double %Val, i32 %power)
6008 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6009 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6010 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6011</pre>
6012
6013<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6014<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6015 specified (positive or negative) power. The order of evaluation of
6016 multiplications is not defined. When a vector of floating point type is
6017 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6018
6019<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6020<p>The second argument is an integer power, and the first is a value to raise to
6021 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6022
6023<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6024<p>This function returns the first value raised to the second power with an
6025 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6026
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6027</div>
6028
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6029<!-- _______________________________________________________________________ -->
6030<div class="doc_subsubsection">
6031 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6032</div>
6033
6034<div class="doc_text">
6035
6036<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6037<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6038 floating point or vector of floating point type. Not all targets support all
6039 types however.</p>
6040
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6041<pre>
6042 declare float @llvm.sin.f32(float %Val)
6043 declare double @llvm.sin.f64(double %Val)
6044 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6045 declare fp128 @llvm.sin.f128(fp128 %Val)
6046 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6047</pre>
6048
6049<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6050<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6051
6052<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6053<p>The argument and return value are floating point numbers of the same
6054 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6055
6056<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6057<p>This function returns the sine of the specified operand, returning the same
6058 values as the libm <tt>sin</tt> functions would, and handles error conditions
6059 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6060
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6061</div>
6062
6063<!-- _______________________________________________________________________ -->
6064<div class="doc_subsubsection">
6065 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6066</div>
6067
6068<div class="doc_text">
6069
6070<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6071<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6072 floating point or vector of floating point type. Not all targets support all
6073 types however.</p>
6074
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6075<pre>
6076 declare float @llvm.cos.f32(float %Val)
6077 declare double @llvm.cos.f64(double %Val)
6078 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6079 declare fp128 @llvm.cos.f128(fp128 %Val)
6080 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6081</pre>
6082
6083<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6084<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6085
6086<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6087<p>The argument and return value are floating point numbers of the same
6088 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6089
6090<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6091<p>This function returns the cosine of the specified operand, returning the same
6092 values as the libm <tt>cos</tt> functions would, and handles error conditions
6093 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6094
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6095</div>
6096
6097<!-- _______________________________________________________________________ -->
6098<div class="doc_subsubsection">
6099 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6100</div>
6101
6102<div class="doc_text">
6103
6104<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6105<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6106 floating point or vector of floating point type. Not all targets support all
6107 types however.</p>
6108
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6109<pre>
6110 declare float @llvm.pow.f32(float %Val, float %Power)
6111 declare double @llvm.pow.f64(double %Val, double %Power)
6112 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6113 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6114 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6115</pre>
6116
6117<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6118<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6119 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6120
6121<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6122<p>The second argument is a floating point power, and the first is a value to
6123 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6124
6125<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6126<p>This function returns the first value raised to the second power, returning
6127 the same values as the libm <tt>pow</tt> functions would, and handles error
6128 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6129
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6130</div>
6131
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6132<!-- ======================================================================= -->
6133<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6134 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6135</div>
6136
6137<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6138
6139<p>LLVM provides intrinsics for a few important bit manipulation operations.
6140 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6141
6142</div>
6143
6144<!-- _______________________________________________________________________ -->
6145<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6146 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6147</div>
6148
6149<div class="doc_text">
6150
6151<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6152<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6153 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6154
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6155<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6156 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6157 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6158 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6159</pre>
6160
6161<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6162<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6163 values with an even number of bytes (positive multiple of 16 bits). These
6164 are useful for performing operations on data that is not in the target's
6165 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6166
6167<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6168<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6169 and low byte of the input i16 swapped. Similarly,
6170 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6171 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6172 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6173 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6174 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6175 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6176
6177</div>
6178
6179<!-- _______________________________________________________________________ -->
6180<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6181 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6182</div>
6183
6184<div class="doc_text">
6185
6186<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6187<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]6188 width. Not all targets support all bit widths however.</p>
6189
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6190<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6191 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6192 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6193 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6194 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6195 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6196</pre>
6197
6198<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6199<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6200 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6201
6202<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6203<p>The only argument is the value to be counted. The argument may be of any
6204 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6205
6206<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6207<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]6208
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6209</div>
6210
6211<!-- _______________________________________________________________________ -->
6212<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6213 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6214</div>
6215
6216<div class="doc_text">
6217
6218<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6219<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6220 integer bit width. Not all targets support all bit widths however.</p>
6221
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6222<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6223 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6224 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6225 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6226 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6227 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6228</pre>
6229
6230<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6231<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6232 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6233
6234<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6235<p>The only argument is the value to be counted. The argument may be of any
6236 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6237
6238<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6239<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6240 zeros in a variable. If the src == 0 then the result is the size in bits of
6241 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6242
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6243</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6244
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6245<!-- _______________________________________________________________________ -->
6246<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6247 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6248</div>
6249
6250<div class="doc_text">
6251
6252<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6253<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6254 integer bit width. Not all targets support all bit widths however.</p>
6255
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6256<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6257 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6258 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6259 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6260 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6261 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6262</pre>
6263
6264<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6265<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6266 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6267
6268<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6269<p>The only argument is the value to be counted. The argument may be of any
6270 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6271
6272<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6273<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6274 zeros in a variable. If the src == 0 then the result is the size in bits of
6275 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6276
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6277</div>
6278
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6279<!-- ======================================================================= -->
6280<div class="doc_subsection">
6281 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6282</div>
6283
6284<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6285
6286<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6287
6288</div>
6289
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6290<!-- _______________________________________________________________________ -->
6291<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6292 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6293</div>
6294
6295<div class="doc_text">
6296
6297<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6298<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]6299 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6300
6301<pre>
6302 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6303 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6304 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6305</pre>
6306
6307<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6308<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6309 a signed addition of the two arguments, and indicate whether an overflow
6310 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6311
6312<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6313<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]6314 be of integer types of any bit width, but they must have the same bit
6315 width. The second element of the result structure must be of
6316 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6317 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6318
6319<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6320<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6321 a signed addition of the two variables. They return a structure &mdash; the
6322 first element of which is the signed summation, and the second element of
6323 which is a bit specifying if the signed summation resulted in an
6324 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6325
6326<h5>Examples:</h5>
6327<pre>
6328 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6329 %sum = extractvalue {i32, i1} %res, 0
6330 %obit = extractvalue {i32, i1} %res, 1
6331 br i1 %obit, label %overflow, label %normal
6332</pre>
6333
6334</div>
6335
6336<!-- _______________________________________________________________________ -->
6337<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6338 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6339</div>
6340
6341<div class="doc_text">
6342
6343<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6344<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]6345 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6346
6347<pre>
6348 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6349 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6350 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6351</pre>
6352
6353<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6354<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6355 an unsigned addition of the two arguments, and indicate whether a carry
6356 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6357
6358<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6359<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]6360 be of integer types of any bit width, but they must have the same bit
6361 width. The second element of the result structure must be of
6362 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6363 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6364
6365<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6366<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6367 an unsigned addition of the two arguments. They return a structure &mdash;
6368 the first element of which is the sum, and the second element of which is a
6369 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6370
6371<h5>Examples:</h5>
6372<pre>
6373 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6374 %sum = extractvalue {i32, i1} %res, 0
6375 %obit = extractvalue {i32, i1} %res, 1
6376 br i1 %obit, label %carry, label %normal
6377</pre>
6378
6379</div>
6380
6381<!-- _______________________________________________________________________ -->
6382<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6383 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6384</div>
6385
6386<div class="doc_text">
6387
6388<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6389<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]6390 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6391
6392<pre>
6393 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6394 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6395 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6396</pre>
6397
6398<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6399<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6400 a signed subtraction of the two arguments, and indicate whether an overflow
6401 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6402
6403<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6404<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]6405 be of integer types of any bit width, but they must have the same bit
6406 width. The second element of the result structure must be of
6407 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6408 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6409
6410<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6411<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6412 a signed subtraction of the two arguments. They return a structure &mdash;
6413 the first element of which is the subtraction, and the second element of
6414 which is a bit specifying if the signed subtraction resulted in an
6415 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6416
6417<h5>Examples:</h5>
6418<pre>
6419 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6420 %sum = extractvalue {i32, i1} %res, 0
6421 %obit = extractvalue {i32, i1} %res, 1
6422 br i1 %obit, label %overflow, label %normal
6423</pre>
6424
6425</div>
6426
6427<!-- _______________________________________________________________________ -->
6428<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6429 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6430</div>
6431
6432<div class="doc_text">
6433
6434<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6435<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]6436 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6437
6438<pre>
6439 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6440 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6441 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6442</pre>
6443
6444<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6445<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6446 an unsigned subtraction of the two arguments, and indicate whether an
6447 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6448
6449<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6450<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]6451 be of integer types of any bit width, but they must have the same bit
6452 width. The second element of the result structure must be of
6453 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6454 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6455
6456<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6457<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6458 an unsigned subtraction of the two arguments. They return a structure &mdash;
6459 the first element of which is the subtraction, and the second element of
6460 which is a bit specifying if the unsigned subtraction resulted in an
6461 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6462
6463<h5>Examples:</h5>
6464<pre>
6465 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6466 %sum = extractvalue {i32, i1} %res, 0
6467 %obit = extractvalue {i32, i1} %res, 1
6468 br i1 %obit, label %overflow, label %normal
6469</pre>
6470
6471</div>
6472
6473<!-- _______________________________________________________________________ -->
6474<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6475 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6476</div>
6477
6478<div class="doc_text">
6479
6480<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6481<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]6482 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6483
6484<pre>
6485 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6486 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6487 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6488</pre>
6489
6490<h5>Overview:</h5>
6491
6492<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6493 a signed multiplication of the two arguments, and indicate whether an
6494 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6495
6496<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6497<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]6498 be of integer types of any bit width, but they must have the same bit
6499 width. The second element of the result structure must be of
6500 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6501 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6502
6503<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6504<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6505 a signed multiplication of the two arguments. They return a structure &mdash;
6506 the first element of which is the multiplication, and the second element of
6507 which is a bit specifying if the signed multiplication resulted in an
6508 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6509
6510<h5>Examples:</h5>
6511<pre>
6512 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6513 %sum = extractvalue {i32, i1} %res, 0
6514 %obit = extractvalue {i32, i1} %res, 1
6515 br i1 %obit, label %overflow, label %normal
6516</pre>
6517
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6518</div>
6519
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6520<!-- _______________________________________________________________________ -->
6521<div class="doc_subsubsection">
6522 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6523</div>
6524
6525<div class="doc_text">
6526
6527<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6528<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]6529 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6530
6531<pre>
6532 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6533 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6534 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6535</pre>
6536
6537<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6538<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6539 a unsigned multiplication of the two arguments, and indicate whether an
6540 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6541
6542<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6543<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]6544 be of integer types of any bit width, but they must have the same bit
6545 width. The second element of the result structure must be of
6546 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6547 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6548
6549<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6550<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6551 an unsigned multiplication of the two arguments. They return a structure
6552 &mdash; the first element of which is the multiplication, and the second
6553 element of which is a bit specifying if the unsigned multiplication resulted
6554 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6555
6556<h5>Examples:</h5>
6557<pre>
6558 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6559 %sum = extractvalue {i32, i1} %res, 0
6560 %obit = extractvalue {i32, i1} %res, 1
6561 br i1 %obit, label %overflow, label %normal
6562</pre>
6563
6564</div>
6565
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6566<!-- ======================================================================= -->
6567<div class="doc_subsection">
6568 <a name="int_debugger">Debugger Intrinsics</a>
6569</div>
6570
6571<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6572
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6573<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6574 prefix), are described in
6575 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6576 Level Debugging</a> document.</p>
6577
6578</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6579
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6580<!-- ======================================================================= -->
6581<div class="doc_subsection">
6582 <a name="int_eh">Exception Handling Intrinsics</a>
6583</div>
6584
6585<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6586
6587<p>The LLVM exception handling intrinsics (which all start with
6588 <tt>llvm.eh.</tt> prefix), are described in
6589 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6590 Handling</a> document.</p>
6591
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6592</div>
6593
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6594<!-- ======================================================================= -->
6595<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6596 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6597</div>
6598
6599<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6600
6601<p>This intrinsic makes it possible to excise one parameter, marked with
6602 the <tt>nest</tt> attribute, from a function. The result is a callable
6603 function pointer lacking the nest parameter - the caller does not need to
6604 provide a value for it. Instead, the value to use is stored in advance in a
6605 "trampoline", a block of memory usually allocated on the stack, which also
6606 contains code to splice the nest value into the argument list. This is used
6607 to implement the GCC nested function address extension.</p>
6608
6609<p>For example, if the function is
6610 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6611 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6612 follows:</p>
6613
6614<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6615<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6616 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6617 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6618 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6619 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6620</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6621</div>
6622
6623<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6624 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6625
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6626</div>
6627
6628<!-- _______________________________________________________________________ -->
6629<div class="doc_subsubsection">
6630 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6631</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6632
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6633<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6634
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6635<h5>Syntax:</h5>
6636<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6637 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]6638</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6639
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6640<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6641<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6642 function pointer suitable for executing it.</p>
6643
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6644<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6645<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6646 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6647 sufficiently aligned block of memory; this memory is written to by the
6648 intrinsic. Note that the size and the alignment are target-specific - LLVM
6649 currently provides no portable way of determining them, so a front-end that
6650 generates this intrinsic needs to have some target-specific knowledge.
6651 The <tt>func</tt> argument must hold a function bitcast to
6652 an <tt>i8*</tt>.</p>
6653
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6654<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6655<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6656 dependent code, turning it into a function. A pointer to this function is
6657 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6658 function pointer type</a> before being called. The new function's signature
6659 is the same as that of <tt>func</tt> with any arguments marked with
6660 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6661 is allowed, and it must be of pointer type. Calling the new function is
6662 equivalent to calling <tt>func</tt> with the same argument list, but
6663 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6664 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6665 by <tt>tramp</tt> is modified, then the effect of any later call to the
6666 returned function pointer is undefined.</p>
6667
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6668</div>
6669
6670<!-- ======================================================================= -->
6671<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6672 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6673</div>
6674
6675<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6676
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6677<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6678 hardware constructs for atomic operations and memory synchronization. This
6679 provides an interface to the hardware, not an interface to the programmer. It
6680 is aimed at a low enough level to allow any programming models or APIs
6681 (Application Programming Interfaces) which need atomic behaviors to map
6682 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6683 hardware provides a "universal IR" for source languages, it also provides a
6684 starting point for developing a "universal" atomic operation and
6685 synchronization IR.</p>
6686
6687<p>These do <em>not</em> form an API such as high-level threading libraries,
6688 software transaction memory systems, atomic primitives, and intrinsic
6689 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6690 application libraries. The hardware interface provided by LLVM should allow
6691 a clean implementation of all of these APIs and parallel programming models.
6692 No one model or paradigm should be selected above others unless the hardware
6693 itself ubiquitously does so.</p>
6694
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6695</div>
6696
6697<!-- _______________________________________________________________________ -->
6698<div class="doc_subsubsection">
6699 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6700</div>
6701<div class="doc_text">
6702<h5>Syntax:</h5>
6703<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6704 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]6705</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6706
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6707<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6708<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6709 specific pairs of memory access types.</p>
6710
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6711<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6712<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6713 The first four arguments enables a specific barrier as listed below. The
6714 fith argument specifies that the barrier applies to io or device or uncached
6715 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6716
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6717<ul>
6718 <li><tt>ll</tt>: load-load barrier</li>
6719 <li><tt>ls</tt>: load-store barrier</li>
6720 <li><tt>sl</tt>: store-load barrier</li>
6721 <li><tt>ss</tt>: store-store barrier</li>
6722 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6723</ul>
6724
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6725<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6726<p>This intrinsic causes the system to enforce some ordering constraints upon
6727 the loads and stores of the program. This barrier does not
6728 indicate <em>when</em> any events will occur, it only enforces
6729 an <em>order</em> in which they occur. For any of the specified pairs of load
6730 and store operations (f.ex. load-load, or store-load), all of the first
6731 operations preceding the barrier will complete before any of the second
6732 operations succeeding the barrier begin. Specifically the semantics for each
6733 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6734
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6735<ul>
6736 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6737 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6738 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6739 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6740 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6741 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6742 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6743 load after the barrier begins.</li>
6744</ul>
6745
6746<p>These semantics are applied with a logical "and" behavior when more than one
6747 is enabled in a single memory barrier intrinsic.</p>
6748
6749<p>Backends may implement stronger barriers than those requested when they do
6750 not support as fine grained a barrier as requested. Some architectures do
6751 not need all types of barriers and on such architectures, these become
6752 noops.</p>
6753
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6754<h5>Example:</h5>
6755<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6756%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6757%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6758 store i32 4, %ptr
6759
6760%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6761 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6762 <i>; guarantee the above finishes</i>
6763 store i32 8, %ptr <i>; before this begins</i>
6764</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6765
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6766</div>
6767
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6768<!-- _______________________________________________________________________ -->
6769<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6770 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6771</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6772
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6773<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6774
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6775<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6776<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6777 any integer bit width and for different address spaces. Not all targets
6778 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6779
6780<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6781 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6782 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6783 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6784 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]6785</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6786
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6787<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6788<p>This loads a value in memory and compares it to a given value. If they are
6789 equal, it stores a new value into the memory.</p>
6790
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6791<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6792<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6793 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6794 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6795 this integer type. While any bit width integer may be used, targets may only
6796 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6797
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6798<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6799<p>This entire intrinsic must be executed atomically. It first loads the value
6800 in memory pointed to by <tt>ptr</tt> and compares it with the
6801 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6802 memory. The loaded value is yielded in all cases. This provides the
6803 equivalent of an atomic compare-and-swap operation within the SSA
6804 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6805
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6806<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6807<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6808%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6809%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6810 store i32 4, %ptr
6811
6812%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6813%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6814 <i>; yields {i32}:result1 = 4</i>
6815%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6816%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6817
6818%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6819%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6820 <i>; yields {i32}:result2 = 8</i>
6821%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6822
6823%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6824</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6825
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6826</div>
6827
6828<!-- _______________________________________________________________________ -->
6829<div class="doc_subsubsection">
6830 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6831</div>
6832<div class="doc_text">
6833<h5>Syntax:</h5>
6834
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6835<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6836 integer bit width. Not all targets support all bit widths however.</p>
6837
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6838<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6839 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6840 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6841 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6842 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]6843</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6844
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6845<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6846<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6847 the value from memory. It then stores the value in <tt>val</tt> in the memory
6848 at <tt>ptr</tt>.</p>
6849
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6850<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6851<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6852 the <tt>val</tt> argument and the result must be integers of the same bit
6853 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6854 integer type. The targets may only lower integer representations they
6855 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6856
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6857<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6858<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6859 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6860 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6861
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6862<h5>Examples:</h5>
6863<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6864%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6865%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6866 store i32 4, %ptr
6867
6868%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6869%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6870 <i>; yields {i32}:result1 = 4</i>
6871%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6872%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6873
6874%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6875%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6876 <i>; yields {i32}:result2 = 8</i>
6877
6878%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6879%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6880</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6881
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6882</div>
6883
6884<!-- _______________________________________________________________________ -->
6885<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6886 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6887
6888</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6889
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6890<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6891
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6892<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6893<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6894 any integer bit width. Not all targets support all bit widths however.</p>
6895
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6896<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6897 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6898 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6899 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6900 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]6901</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6902
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6903<h5>Overview:</h5>
6904<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6905 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6906
6907<h5>Arguments:</h5>
6908<p>The intrinsic takes two arguments, the first a pointer to an integer value
6909 and the second an integer value. The result is also an integer value. These
6910 integer types can have any bit width, but they must all have the same bit
6911 width. The targets may only lower integer representations they support.</p>
6912
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6913<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6914<p>This intrinsic does a series of operations atomically. It first loads the
6915 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6916 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]6917
6918<h5>Examples:</h5>
6919<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6920%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6921%ptr = bitcast i8* %mallocP to i32*
6922 store i32 4, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6923%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6924 <i>; yields {i32}:result1 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6925%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6926 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6927%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6928 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6929%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6930</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6931
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6932</div>
6933
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6934<!-- _______________________________________________________________________ -->
6935<div class="doc_subsubsection">
6936 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6937
6938</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6939
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6940<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6941
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6942<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6943<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6944 any integer bit width and for different address spaces. Not all targets
6945 support all bit widths however.</p>
6946
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6947<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6948 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6949 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6950 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6951 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]6952</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6953
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6954<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6955<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6956 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6957
6958<h5>Arguments:</h5>
6959<p>The intrinsic takes two arguments, the first a pointer to an integer value
6960 and the second an integer value. The result is also an integer value. These
6961 integer types can have any bit width, but they must all have the same bit
6962 width. The targets may only lower integer representations they support.</p>
6963
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6964<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6965<p>This intrinsic does a series of operations atomically. It first loads the
6966 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6967 result to <tt>ptr</tt>. It yields the original value stored
6968 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6969
6970<h5>Examples:</h5>
6971<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]6972%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6973%ptr = bitcast i8* %mallocP to i32*
6974 store i32 8, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6975%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6976 <i>; yields {i32}:result1 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6977%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6978 <i>; yields {i32}:result2 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6979%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6980 <i>; yields {i32}:result3 = 2</i>
6981%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6982</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6983
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6984</div>
6985
6986<!-- _______________________________________________________________________ -->
6987<div class="doc_subsubsection">
6988 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6989 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6990 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6991 <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]6992</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6993
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6994<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6995
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6996<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6997<p>These are overloaded intrinsics. You can
6998 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6999 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7000 bit width and for different address spaces. Not all targets support all bit
7001 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7002
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7003<pre>
7004 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7005 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7006 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7007 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]7008</pre>
7009
7010<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7011 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7012 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7013 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7014 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]7015</pre>
7016
7017<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7018 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7019 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7020 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7021 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]7022</pre>
7023
7024<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7025 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7026 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7027 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7028 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]7029</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7030
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7031<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7032<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7033 the value stored in memory at <tt>ptr</tt>. It yields the original value
7034 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7035
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7036<h5>Arguments:</h5>
7037<p>These intrinsics take two arguments, the first a pointer to an integer value
7038 and the second an integer value. The result is also an integer value. These
7039 integer types can have any bit width, but they must all have the same bit
7040 width. The targets may only lower integer representations they support.</p>
7041
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7042<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7043<p>These intrinsics does a series of operations atomically. They first load the
7044 value stored at <tt>ptr</tt>. They then do the bitwise
7045 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7046 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7047
7048<h5>Examples:</h5>
7049<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7050%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7051%ptr = bitcast i8* %mallocP to i32*
7052 store i32 0x0F0F, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7053%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7054 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7055%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7056 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7057%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7058 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7059%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7060 <i>; yields {i32}:result3 = FF</i>
7061%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7062</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7063
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7064</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7065
7066<!-- _______________________________________________________________________ -->
7067<div class="doc_subsubsection">
7068 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7069 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7070 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7071 <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]7072</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7073
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7074<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7075
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7076<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7077<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7078 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7079 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7080 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7081
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7082<pre>
7083 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7084 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7085 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7086 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]7087</pre>
7088
7089<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7090 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7091 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7092 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7093 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]7094</pre>
7095
7096<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7097 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7098 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7099 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7100 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]7101</pre>
7102
7103<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7104 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7105 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7106 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7107 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]7108</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7109
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7110<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7111<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7112 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7113 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7114
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7115<h5>Arguments:</h5>
7116<p>These intrinsics take two arguments, the first a pointer to an integer value
7117 and the second an integer value. The result is also an integer value. These
7118 integer types can have any bit width, but they must all have the same bit
7119 width. The targets may only lower integer representations they support.</p>
7120
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7121<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7122<p>These intrinsics does a series of operations atomically. They first load the
7123 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7124 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7125 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7126
7127<h5>Examples:</h5>
7128<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7129%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7130%ptr = bitcast i8* %mallocP to i32*
7131 store i32 7, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7132%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7133 <i>; yields {i32}:result0 = 7</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7134%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7135 <i>; yields {i32}:result1 = -2</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7136%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7137 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7138%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7139 <i>; yields {i32}:result3 = 8</i>
7140%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7141</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7142
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7143</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7144
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7145
7146<!-- ======================================================================= -->
7147<div class="doc_subsection">
7148 <a name="int_memorymarkers">Memory Use Markers</a>
7149</div>
7150
7151<div class="doc_text">
7152
7153<p>This class of intrinsics exists to information about the lifetime of memory
7154 objects and ranges where variables are immutable.</p>
7155
7156</div>
7157
7158<!-- _______________________________________________________________________ -->
7159<div class="doc_subsubsection">
7160 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7161</div>
7162
7163<div class="doc_text">
7164
7165<h5>Syntax:</h5>
7166<pre>
7167 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7168</pre>
7169
7170<h5>Overview:</h5>
7171<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7172 object's lifetime.</p>
7173
7174<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7175<p>The first argument is a constant integer representing the size of the
7176 object, or -1 if it is variable sized. The second argument is a pointer to
7177 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7178
7179<h5>Semantics:</h5>
7180<p>This intrinsic indicates that before this point in the code, the value of the
7181 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]7182 never be used and has an undefined value. A load from the pointer that
7183 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7184 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7185
7186</div>
7187
7188<!-- _______________________________________________________________________ -->
7189<div class="doc_subsubsection">
7190 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7191</div>
7192
7193<div class="doc_text">
7194
7195<h5>Syntax:</h5>
7196<pre>
7197 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7198</pre>
7199
7200<h5>Overview:</h5>
7201<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7202 object's lifetime.</p>
7203
7204<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7205<p>The first argument is a constant integer representing the size of the
7206 object, or -1 if it is variable sized. The second argument is a pointer to
7207 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7208
7209<h5>Semantics:</h5>
7210<p>This intrinsic indicates that after this point in the code, the value of the
7211 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7212 never be used and has an undefined value. Any stores into the memory object
7213 following this intrinsic may be removed as dead.
7214
7215</div>
7216
7217<!-- _______________________________________________________________________ -->
7218<div class="doc_subsubsection">
7219 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7220</div>
7221
7222<div class="doc_text">
7223
7224<h5>Syntax:</h5>
7225<pre>
7226 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7227</pre>
7228
7229<h5>Overview:</h5>
7230<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7231 a memory object will not change.</p>
7232
7233<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7234<p>The first argument is a constant integer representing the size of the
7235 object, or -1 if it is variable sized. The second argument is a pointer to
7236 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7237
7238<h5>Semantics:</h5>
7239<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7240 the return value, the referenced memory location is constant and
7241 unchanging.</p>
7242
7243</div>
7244
7245<!-- _______________________________________________________________________ -->
7246<div class="doc_subsubsection">
7247 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7248</div>
7249
7250<div class="doc_text">
7251
7252<h5>Syntax:</h5>
7253<pre>
7254 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7255</pre>
7256
7257<h5>Overview:</h5>
7258<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7259 a memory object are mutable.</p>
7260
7261<h5>Arguments:</h5>
7262<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7263 The second argument is a constant integer representing the size of the
7264 object, or -1 if it is variable sized and the third argument is a pointer
7265 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7266
7267<h5>Semantics:</h5>
7268<p>This intrinsic indicates that the memory is mutable again.</p>
7269
7270</div>
7271
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7272<!-- ======================================================================= -->
7273<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7274 <a name="int_general">General Intrinsics</a>
7275</div>
7276
7277<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7278
7279<p>This class of intrinsics is designed to be generic and has no specific
7280 purpose.</p>
7281
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7282</div>
7283
7284<!-- _______________________________________________________________________ -->
7285<div class="doc_subsubsection">
7286 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7287</div>
7288
7289<div class="doc_text">
7290
7291<h5>Syntax:</h5>
7292<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]7293 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]7294</pre>
7295
7296<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7297<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7298
7299<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7300<p>The first argument is a pointer to a value, the second is a pointer to a
7301 global string, the third is a pointer to a global string which is the source
7302 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7303
7304<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7305<p>This intrinsic allows annotation of local variables with arbitrary strings.
7306 This can be useful for special purpose optimizations that want to look for
7307 these annotations. These have no other defined use, they are ignored by code
7308 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7309
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7310</div>
7311
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7312<!-- _______________________________________________________________________ -->
7313<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7314 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7315</div>
7316
7317<div class="doc_text">
7318
7319<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7320<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7321 any integer bit width.</p>
7322
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7323<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]7324 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7325 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7326 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7327 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7328 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]7329</pre>
7330
7331<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7332<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7333
7334<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7335<p>The first argument is an integer value (result of some expression), the
7336 second is a pointer to a global string, the third is a pointer to a global
7337 string which is the source file name, and the last argument is the line
7338 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7339
7340<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7341<p>This intrinsic allows annotations to be put on arbitrary expressions with
7342 arbitrary strings. This can be useful for special purpose optimizations that
7343 want to look for these annotations. These have no other defined use, they
7344 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7345
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7346</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7347
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7348<!-- _______________________________________________________________________ -->
7349<div class="doc_subsubsection">
7350 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7351</div>
7352
7353<div class="doc_text">
7354
7355<h5>Syntax:</h5>
7356<pre>
7357 declare void @llvm.trap()
7358</pre>
7359
7360<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7361<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7362
7363<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7364<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7365
7366<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7367<p>This intrinsics is lowered to the target dependent trap instruction. If the
7368 target does not have a trap instruction, this intrinsic will be lowered to
7369 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7370
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7371</div>
7372
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7373<!-- _______________________________________________________________________ -->
7374<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7375 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7376</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7377
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7378<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7379
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7380<h5>Syntax:</h5>
7381<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7382 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7383</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7384
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7385<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7386<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7387 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7388 ensure that it is placed on the stack before local variables.</p>
7389
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7390<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7391<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7392 arguments. The first argument is the value loaded from the stack
7393 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7394 that has enough space to hold the value of the guard.</p>
7395
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7396<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7397<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7398 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7399 stack. This is to ensure that if a local variable on the stack is
7400 overwritten, it will destroy the value of the guard. When the function exits,
7401 the guard on the stack is checked against the original guard. If they're
7402 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7403 function.</p>
7404
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7405</div>
7406
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7407<!-- _______________________________________________________________________ -->
7408<div class="doc_subsubsection">
7409 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7410</div>
7411
7412<div class="doc_text">
7413
7414<h5>Syntax:</h5>
7415<pre>
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7416 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7417 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7418</pre>
7419
7420<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7421<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7422 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7423 operation like memcpy will either overflow a buffer that corresponds to
7424 an object, or b) to determine that a runtime check for overflow isn't
7425 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7426 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7427
7428<h5>Arguments:</h5>
7429<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7430 argument is a pointer to or into the <tt>object</tt>. The second argument
7431 is a boolean 0 or 1. This argument determines whether you want the
7432 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7433 1, variables are not allowed.</p>
7434
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7435<h5>Semantics:</h5>
7436<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7437 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7438 (depending on the <tt>type</tt> argument if the size cannot be determined
7439 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7440
7441</div>
7442
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7443<!-- *********************************************************************** -->
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7445<address>
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7451 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7452 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7453 Last modified: $Date$
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