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gerrit-public.fairphone.software / toolchain / llvm-project / 4eb47194326ec2393ba2a9d0977a5796d2612e7f / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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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>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]53 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]54 </ol>
55 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]56 <li><a href="#typesystem">Type System</a>
57 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]58 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]59 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]60 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]61 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_floating">Floating Point Types</a></li>
63 <li><a href="#t_void">Void Type</a></li>
64 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]65 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]66 </ol>
67 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]68 <li><a href="#t_derived">Derived Types</a>
69 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]70 <li><a href="#t_aggregate">Aggregate Types</a>
71 <ol>
72 <li><a href="#t_array">Array Type</a></li>
73 <li><a href="#t_struct">Structure Type</a></li>
74 <li><a href="#t_pstruct">Packed Structure Type</a></li>
75 <li><a href="#t_union">Union Type</a></li>
76 <li><a href="#t_vector">Vector Type</a></li>
77 </ol>
78 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]79 <li><a href="#t_function">Function Type</a></li>
80 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]81 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]82 </ol>
83 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]84 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]87 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]88 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]89 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]90 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
92 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]93 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]94 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]95 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]96 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]97 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]98 <li><a href="#othervalues">Other Values</a>
99 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]100 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]101 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]102 </ol>
103 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]104 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
105 <ol>
106 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]107 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
108 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]109 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
110 Global Variable</a></li>
111 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
112 Global Variable</a></li>
113 </ol>
114 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]115 <li><a href="#instref">Instruction Reference</a>
116 <ol>
117 <li><a href="#terminators">Terminator Instructions</a>
118 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]119 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
120 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]121 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]122 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]125 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]126 </ol>
127 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]128 <li><a href="#binaryops">Binary Operations</a>
129 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]130 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]131 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]136 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
137 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
138 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]139 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
140 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
141 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]142 </ol>
143 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]144 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
145 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]146 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
147 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
148 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]149 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]150 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]152 </ol>
153 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]154 <li><a href="#vectorops">Vector Operations</a>
155 <ol>
156 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
157 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
158 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]159 </ol>
160 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]161 <li><a href="#aggregateops">Aggregate Operations</a>
162 <ol>
163 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
164 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
165 </ol>
166 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]167 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]168 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]169 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]170 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
171 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
172 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]173 </ol>
174 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]175 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]176 <ol>
177 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
178 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
179 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]182 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
184 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
185 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]186 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
187 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]188 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]189 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]190 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]191 <li><a href="#otherops">Other Operations</a>
192 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]193 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
194 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]195 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]196 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]198 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></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 Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]203 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]204 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]205 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
206 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]207 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
208 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]210 </ol>
211 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]212 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
213 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]214 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
215 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]219 <li><a href="#int_codegen">Code Generator Intrinsics</a>
220 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]221 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
222 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
224 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
225 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
226 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]227 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]228 </ol>
229 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]230 <li><a href="#int_libc">Standard C Library Intrinsics</a>
231 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]232 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
233 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]237 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]240 </ol>
241 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]242 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]243 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]244 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]245 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
246 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]248 </ol>
249 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]250 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
251 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]252 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
253 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
256 <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]257 <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]258 </ol>
259 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]260 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
261 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]262 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
263 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]264 </ol>
265 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]266 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]267 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]268 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]269 <ol>
270 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]271 </ol>
272 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]273 <li><a href="#int_atomics">Atomic intrinsics</a>
274 <ol>
275 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
276 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
277 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
278 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
279 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
280 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
281 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
282 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
283 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
284 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
285 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
286 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
287 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
288 </ol>
289 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]290 <li><a href="#int_memorymarkers">Memory Use Markers</a>
291 <ol>
292 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
293 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
294 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
295 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
296 </ol>
297 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]298 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]299 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]301 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]302 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]304 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.trap</tt>' Intrinsic</a></li>
306 <li><a href="#int_stackprotector">
307 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]308 <li><a href="#int_objectsize">
309 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]310 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]311 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]312 </ol>
313 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]314</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]315
316<div class="doc_author">
317 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
318 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]319</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]320
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]321<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]322<div class="doc_section"> <a name="abstract">Abstract </a></div>
323<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]324
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]325<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]326
327<p>This document is a reference manual for the LLVM assembly language. LLVM is
328 a Static Single Assignment (SSA) based representation that provides type
329 safety, low-level operations, flexibility, and the capability of representing
330 'all' high-level languages cleanly. It is the common code representation
331 used throughout all phases of the LLVM compilation strategy.</p>
332
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]333</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]334
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]335<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]336<div class="doc_section"> <a name="introduction">Introduction</a> </div>
337<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]338
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]339<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]340
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]341<p>The LLVM code representation is designed to be used in three different forms:
342 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
343 for fast loading by a Just-In-Time compiler), and as a human readable
344 assembly language representation. This allows LLVM to provide a powerful
345 intermediate representation for efficient compiler transformations and
346 analysis, while providing a natural means to debug and visualize the
347 transformations. The three different forms of LLVM are all equivalent. This
348 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]349
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]350<p>The LLVM representation aims to be light-weight and low-level while being
351 expressive, typed, and extensible at the same time. It aims to be a
352 "universal IR" of sorts, by being at a low enough level that high-level ideas
353 may be cleanly mapped to it (similar to how microprocessors are "universal
354 IR's", allowing many source languages to be mapped to them). By providing
355 type information, LLVM can be used as the target of optimizations: for
356 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]357 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]358 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]359
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]360</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]361
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]362<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]363<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]364
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]365<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]366
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]367<p>It is important to note that this document describes 'well formed' LLVM
368 assembly language. There is a difference between what the parser accepts and
369 what is considered 'well formed'. For example, the following instruction is
370 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]371
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]372<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]373<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]375</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]376</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]377
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</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_mul">mul</a> i32 %X, 8
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>After strength reduction:</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>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]449%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]450</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]451</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]452
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]453<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]455<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]456<pre>
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]457%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
458%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]459%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]460</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]461</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]462
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]463<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
464 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]465
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]466<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]467 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]468 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]469
470 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]471 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]472
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]473 <li>Unnamed temporaries are numbered sequentially</li>
474</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]475
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]476<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]477 demonstrating instructions, we will follow an instruction with a comment that
478 defines the type and name of value produced. Comments are shown in italic
479 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]480
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]481</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]482
483<!-- *********************************************************************** -->
484<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
485<!-- *********************************************************************** -->
486
487<!-- ======================================================================= -->
488<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
489</div>
490
491<div class="doc_text">
492
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]493<p>LLVM programs are composed of "Module"s, each of which is a translation unit
494 of the input programs. Each module consists of functions, global variables,
495 and symbol table entries. Modules may be combined together with the LLVM
496 linker, which merges function (and global variable) definitions, resolves
497 forward declarations, and merges symbol table entries. Here is an example of
498 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]499
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]500<div class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]501<pre>
502<i>; Declare the string constant as a global constant.</i>
503<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]504
505<i>; External declaration of the puts function</i>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]506<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]507
508<i>; Definition of main function</i>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]509define i32 @main() { <i>; i32()* </i>
510 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]511 %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]512
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]513 <i>; Call puts function to write out the string to stdout.</i>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]514 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]515 <a href="#i_ret">ret</a> i32 0<br>}
516
517<i>; Named metadata</i>
518!1 = metadata !{i32 41}
519!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]520</pre>
521</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]522
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]523<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]524 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]525 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]526 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
527 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]528
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]529<p>In general, a module is made up of a list of global values, where both
530 functions and global variables are global values. Global values are
531 represented by a pointer to a memory location (in this case, a pointer to an
532 array of char, and a pointer to a function), and have one of the
533 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]534
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]535</div>
536
537<!-- ======================================================================= -->
538<div class="doc_subsection">
539 <a name="linkage">Linkage Types</a>
540</div>
541
542<div class="doc_text">
543
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]544<p>All Global Variables and Functions have one of the following types of
545 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]546
547<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]549 <dd>Global values with private linkage are only directly accessible by objects
550 in the current module. In particular, linking code into a module with an
551 private global value may cause the private to be renamed as necessary to
552 avoid collisions. Because the symbol is private to the module, all
553 references can be updated. This doesn't show up in any symbol table in the
554 object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]555
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]557 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere7f064e2009-08-24 04:32:16 +0000[diff] [blame]558 removed by the linker after evaluation. Note that (unlike private
559 symbols) linker_private symbols are subject to coalescing by the linker:
560 weak symbols get merged and redefinitions are rejected. However, unlike
561 normal strong symbols, they are removed by the linker from the final
562 linked image (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]563
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]565 <dd>Similar to private, but the value shows as a local symbol
566 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
567 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]568
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]570 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]571 into the object file corresponding to the LLVM module. They exist to
572 allow inlining and other optimizations to take place given knowledge of
573 the definition of the global, which is known to be somewhere outside the
574 module. Globals with <tt>available_externally</tt> linkage are allowed to
575 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
576 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]577
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]578 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]579 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]580 the same name when linkage occurs. This can be used to implement
581 some forms of inline functions, templates, or other code which must be
582 generated in each translation unit that uses it, but where the body may
583 be overridden with a more definitive definition later. Unreferenced
584 <tt>linkonce</tt> globals are allowed to be discarded. Note that
585 <tt>linkonce</tt> linkage does not actually allow the optimizer to
586 inline the body of this function into callers because it doesn't know if
587 this definition of the function is the definitive definition within the
588 program or whether it will be overridden by a stronger definition.
589 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
590 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]591
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]592 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]593 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
594 <tt>linkonce</tt> linkage, except that unreferenced globals with
595 <tt>weak</tt> linkage may not be discarded. This is used for globals that
596 are declared "weak" in C source code.</dd>
597
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
600 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
601 global scope.
602 Symbols with "<tt>common</tt>" linkage are merged in the same way as
603 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]604 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]605 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]606 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
607 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]608
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]609
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]611 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]612 pointer to array type. When two global variables with appending linkage
613 are linked together, the two global arrays are appended together. This is
614 the LLVM, typesafe, equivalent of having the system linker append together
615 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]616
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]617 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]618 <dd>The semantics of this linkage follow the ELF object file model: the symbol
619 is weak until linked, if not linked, the symbol becomes null instead of
620 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]621
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
623 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]624 <dd>Some languages allow differing globals to be merged, such as two functions
625 with different semantics. Other languages, such as <tt>C++</tt>, ensure
626 that only equivalent globals are ever merged (the "one definition rule" -
627 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
628 and <tt>weak_odr</tt> linkage types to indicate that the global will only
629 be merged with equivalent globals. These linkage types are otherwise the
630 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]631
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]632 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]633 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]634 visible, meaning that it participates in linkage and can be used to
635 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]636</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]637
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]638<p>The next two types of linkage are targeted for Microsoft Windows platform
639 only. They are designed to support importing (exporting) symbols from (to)
640 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]641
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]642<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]643 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]644 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]645 or variable via a global pointer to a pointer that is set up by the DLL
646 exporting the symbol. On Microsoft Windows targets, the pointer name is
647 formed by combining <code>__imp_</code> and the function or variable
648 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]649
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]650 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]651 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]652 pointer to a pointer in a DLL, so that it can be referenced with the
653 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
654 name is formed by combining <code>__imp_</code> and the function or
655 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]656</dl>
657
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]658<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
659 another module defined a "<tt>.LC0</tt>" variable and was linked with this
660 one, one of the two would be renamed, preventing a collision. Since
661 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
662 declarations), they are accessible outside of the current module.</p>
663
664<p>It is illegal for a function <i>declaration</i> to have any linkage type
665 other than "externally visible", <tt>dllimport</tt>
666 or <tt>extern_weak</tt>.</p>
667
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]668<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]669 or <tt>weak_odr</tt> linkages.</p>
670
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]671</div>
672
673<!-- ======================================================================= -->
674<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]675 <a name="callingconv">Calling Conventions</a>
676</div>
677
678<div class="doc_text">
679
680<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]681 and <a href="#i_invoke">invokes</a> can all have an optional calling
682 convention specified for the call. The calling convention of any pair of
683 dynamic caller/callee must match, or the behavior of the program is
684 undefined. The following calling conventions are supported by LLVM, and more
685 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]686
687<dl>
688 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]689 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]690 specified) matches the target C calling conventions. This calling
691 convention supports varargs function calls and tolerates some mismatch in
692 the declared prototype and implemented declaration of the function (as
693 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]694
695 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]696 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]697 (e.g. by passing things in registers). This calling convention allows the
698 target to use whatever tricks it wants to produce fast code for the
699 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]700 (Application Binary Interface).
701 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]702 when this or the GHC convention is used.</a> 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
706 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]708 as possible under the assumption that the call is not commonly executed.
709 As such, these calls often preserve all registers so that the call does
710 not break any live ranges in the caller side. This calling convention
711 does not support varargs and requires the prototype of all callees to
712 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]713
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]714 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
715 <dd>This calling convention has been implemented specifically for use by the
716 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
717 It passes everything in registers, going to extremes to achieve this by
718 disabling callee save registers. This calling convention should not be
719 used lightly but only for specific situations such as an alternative to
720 the <em>register pinning</em> performance technique often used when
721 implementing functional programming languages.At the moment only X86
722 supports this convention and it has the following limitations:
723 <ul>
724 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
725 floating point types are supported.</li>
726 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
727 6 floating point parameters.</li>
728 </ul>
729 This calling convention supports
730 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
731 requires both the caller and callee are using it.
732 </dd>
733
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]734 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]735 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]736 target-specific calling conventions to be used. Target specific calling
737 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]738</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]739
740<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]741 support Pascal conventions or any other well-known target-independent
742 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]743
744</div>
745
746<!-- ======================================================================= -->
747<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]748 <a name="visibility">Visibility Styles</a>
749</div>
750
751<div class="doc_text">
752
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]753<p>All Global Variables and Functions have one of the following visibility
754 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]755
756<dl>
757 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]758 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]759 that the declaration is visible to other modules and, in shared libraries,
760 means that the declared entity may be overridden. On Darwin, default
761 visibility means that the declaration is visible to other modules. Default
762 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]763
764 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]765 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]766 object if they are in the same shared object. Usually, hidden visibility
767 indicates that the symbol will not be placed into the dynamic symbol
768 table, so no other module (executable or shared library) can reference it
769 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]770
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]771 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]772 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]773 the dynamic symbol table, but that references within the defining module
774 will bind to the local symbol. That is, the symbol cannot be overridden by
775 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]776</dl>
777
778</div>
779
780<!-- ======================================================================= -->
781<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]782 <a name="namedtypes">Named Types</a>
783</div>
784
785<div class="doc_text">
786
787<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]788 it easier to read the IR and make the IR more condensed (particularly when
789 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]790
791<div class="doc_code">
792<pre>
793%mytype = type { %mytype*, i32 }
794</pre>
795</div>
796
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]797<p>You may give a name to any <a href="#typesystem">type</a> except
798 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
799 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]800
801<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]802 and that you can therefore specify multiple names for the same type. This
803 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
804 uses structural typing, the name is not part of the type. When printing out
805 LLVM IR, the printer will pick <em>one name</em> to render all types of a
806 particular shape. This means that if you have code where two different
807 source types end up having the same LLVM type, that the dumper will sometimes
808 print the "wrong" or unexpected type. This is an important design point and
809 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]810
811</div>
812
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]813<!-- ======================================================================= -->
814<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]815 <a name="globalvars">Global Variables</a>
816</div>
817
818<div class="doc_text">
819
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]820<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]821 instead of run-time. Global variables may optionally be initialized, may
822 have an explicit section to be placed in, and may have an optional explicit
823 alignment specified. A variable may be defined as "thread_local", which
824 means that it will not be shared by threads (each thread will have a
825 separated copy of the variable). A variable may be defined as a global
826 "constant," which indicates that the contents of the variable
827 will <b>never</b> be modified (enabling better optimization, allowing the
828 global data to be placed in the read-only section of an executable, etc).
829 Note that variables that need runtime initialization cannot be marked
830 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]831
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]832<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
833 constant, even if the final definition of the global is not. This capability
834 can be used to enable slightly better optimization of the program, but
835 requires the language definition to guarantee that optimizations based on the
836 'constantness' are valid for the translation units that do not include the
837 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]838
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]839<p>As SSA values, global variables define pointer values that are in scope
840 (i.e. they dominate) all basic blocks in the program. Global variables
841 always define a pointer to their "content" type because they describe a
842 region of memory, and all memory objects in LLVM are accessed through
843 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]844
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]845<p>A global variable may be declared to reside in a target-specific numbered
846 address space. For targets that support them, address spaces may affect how
847 optimizations are performed and/or what target instructions are used to
848 access the variable. The default address space is zero. The address space
849 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]850
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]851<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]852 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]853
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]854<p>An explicit alignment may be specified for a global, which must be a power
855 of 2. If not present, or if the alignment is set to zero, the alignment of
856 the global is set by the target to whatever it feels convenient. If an
857 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]858 alignment. Targets and optimizers are not allowed to over-align the global
859 if the global has an assigned section. In this case, the extra alignment
860 could be observable: for example, code could assume that the globals are
861 densely packed in their section and try to iterate over them as an array,
862 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]863
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]864<p>For example, the following defines a global in a numbered address space with
865 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]866
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]867<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]868<pre>
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]869@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]870</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]871</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]872
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]873</div>
874
875
876<!-- ======================================================================= -->
877<div class="doc_subsection">
878 <a name="functionstructure">Functions</a>
879</div>
880
881<div class="doc_text">
882
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]883<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]884 optional <a href="#linkage">linkage type</a>, an optional
885 <a href="#visibility">visibility style</a>, an optional
886 <a href="#callingconv">calling convention</a>, a return type, an optional
887 <a href="#paramattrs">parameter attribute</a> for the return type, a function
888 name, a (possibly empty) argument list (each with optional
889 <a href="#paramattrs">parameter attributes</a>), optional
890 <a href="#fnattrs">function attributes</a>, an optional section, an optional
891 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
892 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]893
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]894<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
895 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]896 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#callingconv">calling convention</a>, a return type, an optional
898 <a href="#paramattrs">parameter attribute</a> for the return type, a function
899 name, a possibly empty list of arguments, an optional alignment, and an
900 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]901
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]902<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]903 (Control Flow Graph) for the function. Each basic block may optionally start
904 with a label (giving the basic block a symbol table entry), contains a list
905 of instructions, and ends with a <a href="#terminators">terminator</a>
906 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]907
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]908<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]909 executed on entrance to the function, and it is not allowed to have
910 predecessor basic blocks (i.e. there can not be any branches to the entry
911 block of a function). Because the block can have no predecessors, it also
912 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]913
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]914<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]915 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]916
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]917<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]918 the alignment is set to zero, the alignment of the function is set by the
919 target to whatever it feels convenient. If an explicit alignment is
920 specified, the function is forced to have at least that much alignment. All
921 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]922
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]923<h5>Syntax:</h5>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]924<div class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]925<pre>
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]926define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]927 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
928 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
929 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
930 [<a href="#gc">gc</a>] { ... }
931</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]932</div>
933
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]949<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]950<pre>
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]951@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]952</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]953</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]954
955</div>
956
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]957<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]958<div class="doc_subsection">
959 <a name="namedmetadatastructure">Named Metadata</a>
960</div>
961
962<div class="doc_text">
963
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]964<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
965 nodes</a> (but not metadata strings) and null are the only valid operands for
966 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]967
968<h5>Syntax:</h5>
969<div class="doc_code">
970<pre>
971!1 = metadata !{metadata !"one"}
972!name = !{null, !1}
973</pre>
974</div>
975
976</div>
977
978<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]993
994<div class="doc_code">
995<pre>
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]996declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]997declare i32 @atoi(i8 zeroext)
998declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]999</pre>
1000</div>
1001
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1002<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1003 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1004
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1005<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1006
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1007<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1008 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1009 <dd>This indicates to the code generator that the parameter or return value
1010 should be zero-extended to a 32-bit value by the caller (for a parameter)
1011 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1012
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1014 <dd>This indicates to the code generator that the parameter or return value
1015 should be sign-extended to a 32-bit value by the caller (for a parameter)
1016 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1017
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates that this parameter or return value should be treated in a
1020 special target-dependent fashion during while emitting code for a function
1021 call or return (usually, by putting it in a register as opposed to memory,
1022 though some targets use it to distinguish between two different kinds of
1023 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1024
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1025 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1026 <dd>This indicates that the pointer parameter should really be passed by value
1027 to the function. The attribute implies that a hidden copy of the pointee
1028 is made between the caller and the callee, so the callee is unable to
1029 modify the value in the callee. This attribute is only valid on LLVM
1030 pointer arguments. It is generally used to pass structs and arrays by
1031 value, but is also valid on pointers to scalars. The copy is considered
1032 to belong to the caller not the callee (for example,
1033 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1034 <tt>byval</tt> parameters). This is not a valid attribute for return
1035 values. The byval attribute also supports specifying an alignment with
1036 the align attribute. This has a target-specific effect on the code
1037 generator that usually indicates a desired alignment for the synthesized
1038 stack slot.</dd>
1039
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1040 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This indicates that the pointer parameter specifies the address of a
1042 structure that is the return value of the function in the source program.
1043 This pointer must be guaranteed by the caller to be valid: loads and
1044 stores to the structure may be assumed by the callee to not to trap. This
1045 may only be applied to the first parameter. This is not a valid attribute
1046 for return values. </dd>
1047
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1048 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1049 <dd>This indicates that the pointer does not alias any global or any other
1050 parameter. The caller is responsible for ensuring that this is the
1051 case. On a function return value, <tt>noalias</tt> additionally indicates
1052 that the pointer does not alias any other pointers visible to the
1053 caller. For further details, please see the discussion of the NoAlias
1054 response in
1055 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1056 analysis</a>.</dd>
1057
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1058 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This indicates that the callee does not make any copies of the pointer
1060 that outlive the callee itself. This is not a valid attribute for return
1061 values.</dd>
1062
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1063 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This indicates that the pointer parameter can be excised using the
1065 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1066 attribute for return values.</dd>
1067</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1068
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1069</div>
1070
1071<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1072<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1073 <a name="gc">Garbage Collector Names</a>
1074</div>
1075
1076<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1077
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1078<p>Each function may specify a garbage collector name, which is simply a
1079 string:</p>
1080
1081<div class="doc_code">
1082<pre>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1083define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1084</pre>
1085</div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1086
1087<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1088 collector which will cause the compiler to alter its output in order to
1089 support the named garbage collection algorithm.</p>
1090
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1091</div>
1092
1093<!-- ======================================================================= -->
1094<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1095 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1096</div>
1097
1098<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1099
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1100<p>Function attributes are set to communicate additional information about a
1101 function. Function attributes are considered to be part of the function, not
1102 of the function type, so functions with different parameter attributes can
1103 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1104
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1105<p>Function attributes are simple keywords that follow the type specified. If
1106 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1107
1108<div class="doc_code">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1109<pre>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1110define void @f() noinline { ... }
1111define void @f() alwaysinline { ... }
1112define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1113define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1114</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1115</div>
1116
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1117<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1118 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1119 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1120 the backend should forcibly align the stack pointer. Specify the
1121 desired alignment, which must be a power of two, in parentheses.
1122
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1123 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1124 <dd>This attribute indicates that the inliner should attempt to inline this
1125 function into callers whenever possible, ignoring any active inlining size
1126 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1127
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1128 <dt><tt><b>inlinehint</b></tt></dt>
1129 <dd>This attribute indicates that the source code contained a hint that inlining
1130 this function is desirable (such as the "inline" keyword in C/C++). It
1131 is just a hint; it imposes no requirements on the inliner.</dd>
1132
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1133 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1134 <dd>This attribute indicates that the inliner should never inline this
1135 function in any situation. This attribute may not be used together with
1136 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1137
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1138 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1139 <dd>This attribute suggests that optimization passes and code generator passes
1140 make choices that keep the code size of this function low, and otherwise
1141 do optimizations specifically to reduce code size.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1142
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This function attribute indicates that the function never returns
1145 normally. This produces undefined behavior at runtime if the function
1146 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1147
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1148 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1149 <dd>This function attribute indicates that the function never returns with an
1150 unwind or exceptional control flow. If the function does unwind, its
1151 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1152
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1153 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1154 <dd>This attribute indicates that the function computes its result (or decides
1155 to unwind an exception) based strictly on its arguments, without
1156 dereferencing any pointer arguments or otherwise accessing any mutable
1157 state (e.g. memory, control registers, etc) visible to caller functions.
1158 It does not write through any pointer arguments
1159 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1160 changes any state visible to callers. This means that it cannot unwind
1161 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1162 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1163
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1164 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1165 <dd>This attribute indicates that the function does not write through any
1166 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1167 arguments) or otherwise modify any state (e.g. memory, control registers,
1168 etc) visible to caller functions. It may dereference pointer arguments
1169 and read state that may be set in the caller. A readonly function always
1170 returns the same value (or unwinds an exception identically) when called
1171 with the same set of arguments and global state. It cannot unwind an
1172 exception by calling the <tt>C++</tt> exception throwing methods, but may
1173 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1174
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1175 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1176 <dd>This attribute indicates that the function should emit a stack smashing
1177 protector. It is in the form of a "canary"&mdash;a random value placed on
1178 the stack before the local variables that's checked upon return from the
1179 function to see if it has been overwritten. A heuristic is used to
1180 determine if a function needs stack protectors or not.<br>
1181<br>
1182 If a function that has an <tt>ssp</tt> attribute is inlined into a
1183 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1184 function will have an <tt>ssp</tt> attribute.</dd>
1185
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1186 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1187 <dd>This attribute indicates that the function should <em>always</em> emit a
1188 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1189 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1190<br>
1191 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1192 function that doesn't have an <tt>sspreq</tt> attribute or which has
1193 an <tt>ssp</tt> attribute, then the resulting function will have
1194 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1195
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1197 <dd>This attribute indicates that the code generator should not use a red
1198 zone, even if the target-specific ABI normally permits it.</dd>
1199
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This attributes disables implicit floating point instructions.</dd>
1202
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1204 <dd>This attribute disables prologue / epilogue emission for the function.
1205 This can have very system-specific consequences.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1206</dl>
1207
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1208</div>
1209
1210<!-- ======================================================================= -->
1211<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1212 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1213</div>
1214
1215<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1216
1217<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1218 the GCC "file scope inline asm" blocks. These blocks are internally
1219 concatenated by LLVM and treated as a single unit, but may be separated in
1220 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1221
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1222<div class="doc_code">
1223<pre>
1224module asm "inline asm code goes here"
1225module asm "more can go here"
1226</pre>
1227</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1228
1229<p>The strings can contain any character by escaping non-printable characters.
1230 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]1231 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1232
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1233<p>The inline asm code is simply printed to the machine code .s file when
1234 assembly code is generated.</p>
1235
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1236</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1237
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1238<!-- ======================================================================= -->
1239<div class="doc_subsection">
1240 <a name="datalayout">Data Layout</a>
1241</div>
1242
1243<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1244
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1245<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1246 data is to be laid out in memory. The syntax for the data layout is
1247 simply:</p>
1248
1249<div class="doc_code">
1250<pre>
1251target datalayout = "<i>layout specification</i>"
1252</pre>
1253</div>
1254
1255<p>The <i>layout specification</i> consists of a list of specifications
1256 separated by the minus sign character ('-'). Each specification starts with
1257 a letter and may include other information after the letter to define some
1258 aspect of the data layout. The specifications accepted are as follows:</p>
1259
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1260<dl>
1261 <dt><tt>E</tt></dt>
1262 <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]1263 bits with the most significance have the lowest address location.</dd>
1264
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1265 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1266 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1267 the bits with the least significance have the lowest address
1268 location.</dd>
1269
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1270 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1271 <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]1272 <i>preferred</i> alignments. All sizes are in bits. Specifying
1273 the <i>pref</i> alignment is optional. If omitted, the
1274 preceding <tt>:</tt> should be omitted too.</dd>
1275
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1276 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1277 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1278 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1279
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1280 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1281 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1282 <i>size</i>.</dd>
1283
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1284 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1285 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1286 <i>size</i>. Only values of <i>size</i> that are supported by the target
1287 will work. 32 (float) and 64 (double) are supported on all targets;
1288 80 or 128 (different flavors of long double) are also supported on some
1289 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1290
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1291 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1292 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1293 <i>size</i>.</dd>
1294
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1295 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1296 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1297 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1298
1299 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1300 <dd>This specifies a set of native integer widths for the target CPU
1301 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1302 "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]1303 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1304 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1305</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1306
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1307<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1308 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1309 specifications in the <tt>datalayout</tt> keyword. The default specifications
1310 are given in this list:</p>
1311
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1312<ul>
1313 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1314 <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]1315 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1316 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1317 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1318 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1319 <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]1320 alignment of 64-bits</li>
1321 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1322 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1323 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1324 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1325 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1326 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1327</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1328
1329<p>When LLVM is determining the alignment for a given type, it uses the
1330 following rules:</p>
1331
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1332<ol>
1333 <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]1334 specification is used.</li>
1335
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1336 <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]1337 smallest integer type that is larger than the bitwidth of the sought type
1338 is used. If none of the specifications are larger than the bitwidth then
1339 the the largest integer type is used. For example, given the default
1340 specifications above, the i7 type will use the alignment of i8 (next
1341 largest) while both i65 and i256 will use the alignment of i64 (largest
1342 specified).</li>
1343
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1344 <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]1345 largest vector type that is smaller than the sought vector type will be
1346 used as a fall back. This happens because &lt;128 x double&gt; can be
1347 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1348</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1349
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1350</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1351
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1352<!-- ======================================================================= -->
1353<div class="doc_subsection">
1354 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1355</div>
1356
1357<div class="doc_text">
1358
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1359<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1360with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1361is undefined. Pointer values are associated with address ranges
1362according to the following rules:</p>
1363
1364<ul>
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1365 <li>A pointer value formed from a
1366 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1367 is associated with the addresses associated with the first operand
1368 of the <tt>getelementptr</tt>.</li>
1369 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1370 range of the variable's storage.</li>
1371 <li>The result value of an allocation instruction is associated with
1372 the address range of the allocated storage.</li>
1373 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1374 no address.</li>
1375 <li>A pointer value formed by an
1376 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1377 address ranges of all pointer values that contribute (directly or
1378 indirectly) to the computation of the pointer's value.</li>
1379 <li>The result value of a
1380 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1381 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1382 <li>An integer constant other than zero or a pointer value returned
1383 from a function not defined within LLVM may be associated with address
1384 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1385 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1386 allocated by mechanisms provided by LLVM.</li>
1387 </ul>
1388
1389<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1390<tt><a href="#i_load">load</a></tt> merely indicates the size and
1391alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame^]1392interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1393<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1394and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1395
1396<p>Consequently, type-based alias analysis, aka TBAA, aka
1397<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1398LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1399additional information which specialized optimization passes may use
1400to implement type-based alias analysis.</p>
1401
1402</div>
1403
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1404<!-- ======================================================================= -->
1405<div class="doc_subsection">
1406 <a name="volatile">Volatile Memory Accesses</a>
1407</div>
1408
1409<div class="doc_text">
1410
1411<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1412href="#i_store"><tt>store</tt></a>s, and <a
1413href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1414The optimizers must not change the number of volatile operations or change their
1415order of execution relative to other volatile operations. The optimizers
1416<i>may</i> change the order of volatile operations relative to non-volatile
1417operations. This is not Java's "volatile" and has no cross-thread
1418synchronization behavior.</p>
1419
1420</div>
1421
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1422<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1423<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1424<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1425
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1426<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1427
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1428<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1429 intermediate representation. Being typed enables a number of optimizations
1430 to be performed on the intermediate representation directly, without having
1431 to do extra analyses on the side before the transformation. A strong type
1432 system makes it easier to read the generated code and enables novel analyses
1433 and transformations that are not feasible to perform on normal three address
1434 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1435
1436</div>
1437
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1438<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1439<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1440Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1441
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1442<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1443
1444<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1445
1446<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1447 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1448 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1449 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1450 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1451 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1452 </tr>
1453 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1454 <td><a href="#t_floating">floating point</a></td>
1455 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1456 </tr>
1457 <tr>
1458 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1459 <td><a href="#t_integer">integer</a>,
1460 <a href="#t_floating">floating point</a>,
1461 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1462 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1463 <a href="#t_struct">structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1464 <a href="#t_union">union</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1465 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1466 <a href="#t_label">label</a>,
1467 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1468 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1469 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1470 <tr>
1471 <td><a href="#t_primitive">primitive</a></td>
1472 <td><a href="#t_label">label</a>,
1473 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1474 <a href="#t_floating">floating point</a>,
1475 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1476 </tr>
1477 <tr>
1478 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1479 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1480 <a href="#t_function">function</a>,
1481 <a href="#t_pointer">pointer</a>,
1482 <a href="#t_struct">structure</a>,
1483 <a href="#t_pstruct">packed structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1484 <a href="#t_union">union</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1485 <a href="#t_vector">vector</a>,
1486 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1487 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1488 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1489 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1490</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1491
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1492<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1493 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1494 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1495
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1496</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1497
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1498<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1499<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1500
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1501<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1502
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1503<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1504 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1505
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1506</div>
1507
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1508<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1509<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1510
1511<div class="doc_text">
1512
1513<h5>Overview:</h5>
1514<p>The integer type is a very simple type that simply specifies an arbitrary
1515 bit width for the integer type desired. Any bit width from 1 bit to
1516 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1517
1518<h5>Syntax:</h5>
1519<pre>
1520 iN
1521</pre>
1522
1523<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1524 value.</p>
1525
1526<h5>Examples:</h5>
1527<table class="layout">
1528 <tr class="layout">
1529 <td class="left"><tt>i1</tt></td>
1530 <td class="left">a single-bit integer.</td>
1531 </tr>
1532 <tr class="layout">
1533 <td class="left"><tt>i32</tt></td>
1534 <td class="left">a 32-bit integer.</td>
1535 </tr>
1536 <tr class="layout">
1537 <td class="left"><tt>i1942652</tt></td>
1538 <td class="left">a really big integer of over 1 million bits.</td>
1539 </tr>
1540</table>
1541
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1542</div>
1543
1544<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1545<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1546
1547<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1548
1549<table>
1550 <tbody>
1551 <tr><th>Type</th><th>Description</th></tr>
1552 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1553 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1554 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1555 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1556 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1557 </tbody>
1558</table>
1559
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1560</div>
1561
1562<!-- _______________________________________________________________________ -->
1563<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1564
1565<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1566
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1567<h5>Overview:</h5>
1568<p>The void type does not represent any value and has no size.</p>
1569
1570<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1571<pre>
1572 void
1573</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1574
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1575</div>
1576
1577<!-- _______________________________________________________________________ -->
1578<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1579
1580<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1581
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1582<h5>Overview:</h5>
1583<p>The label type represents code labels.</p>
1584
1585<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1586<pre>
1587 label
1588</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1589
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1590</div>
1591
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1592<!-- _______________________________________________________________________ -->
1593<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1594
1595<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1596
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1597<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1598<p>The metadata type represents embedded metadata. No derived types may be
1599 created from metadata except for <a href="#t_function">function</a>
1600 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1601
1602<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1603<pre>
1604 metadata
1605</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1606
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1607</div>
1608
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1609
1610<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1611<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1612
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1613<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1614
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1615<p>The real power in LLVM comes from the derived types in the system. This is
1616 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1617 useful types. Each of these types contain one or more element types which
1618 may be a primitive type, or another derived type. For example, it is
1619 possible to have a two dimensional array, using an array as the element type
1620 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1621
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1622
1623</div>
1624
1625<!-- _______________________________________________________________________ -->
1626<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1627
1628<div class="doc_text">
1629
1630<p>Aggregate Types are a subset of derived types that can contain multiple
1631 member types. <a href="#t_array">Arrays</a>,
1632 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1633 <a href="#t_union">unions</a> are aggregate types.</p>
1634
1635</div>
1636
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1637</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1638
1639<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1640<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1641
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1642<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1643
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1644<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1645<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1646 sequentially in memory. The array type requires a size (number of elements)
1647 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1648
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1649<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1650<pre>
1651 [&lt;# elements&gt; x &lt;elementtype&gt;]
1652</pre>
1653
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1654<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1655 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1656
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1657<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1658<table class="layout">
1659 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1660 <td class="left"><tt>[40 x i32]</tt></td>
1661 <td class="left">Array of 40 32-bit integer values.</td>
1662 </tr>
1663 <tr class="layout">
1664 <td class="left"><tt>[41 x i32]</tt></td>
1665 <td class="left">Array of 41 32-bit integer values.</td>
1666 </tr>
1667 <tr class="layout">
1668 <td class="left"><tt>[4 x i8]</tt></td>
1669 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1670 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1671</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1672<p>Here are some examples of multidimensional arrays:</p>
1673<table class="layout">
1674 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1675 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1676 <td class="left">3x4 array of 32-bit integer values.</td>
1677 </tr>
1678 <tr class="layout">
1679 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1680 <td class="left">12x10 array of single precision floating point values.</td>
1681 </tr>
1682 <tr class="layout">
1683 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1684 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1685 </tr>
1686</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1687
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1688<p>There is no restriction on indexing beyond the end of the array implied by
1689 a static type (though there are restrictions on indexing beyond the bounds
1690 of an allocated object in some cases). This means that single-dimension
1691 'variable sized array' addressing can be implemented in LLVM with a zero
1692 length array type. An implementation of 'pascal style arrays' in LLVM could
1693 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1694
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1695</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1696
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1697<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1698<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1699
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1700<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1701
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1702<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1703<p>The function type can be thought of as a function signature. It consists of
1704 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]1705 function type is a scalar type, a void type, a struct type, or a union
1706 type. If the return type is a struct type then all struct elements must be
1707 of first class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1708
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1709<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1710<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1711 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1712</pre>
1713
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1714<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]1715 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1716 which indicates that the function takes a variable number of arguments.
1717 Variable argument functions can access their arguments with
1718 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1719 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1720 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1721
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1722<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1723<table class="layout">
1724 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1725 <td class="left"><tt>i32 (i32)</tt></td>
1726 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1727 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1728 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1729 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1730 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1731 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1732 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1733 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1734 </td>
1735 </tr><tr class="layout">
1736 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1737 <td class="left">A vararg function that takes at least one
1738 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1739 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1740 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1741 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1742 </tr><tr class="layout">
1743 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1744 <td class="left">A function taking an <tt>i32</tt>, returning a
1745 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1746 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1747 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1748</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1749
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1750</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1751
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1752<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1753<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1754
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1755<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1756
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1757<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1758<p>The structure type is used to represent a collection of data members together
1759 in memory. The packing of the field types is defined to match the ABI of the
1760 underlying processor. The elements of a structure may be any type that has a
1761 size.</p>
1762
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1763<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1764 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1765 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1766 Structures in registers are accessed using the
1767 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1768 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1769<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1770<pre>
1771 { &lt;type list&gt; }
1772</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1773
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1774<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1775<table class="layout">
1776 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1777 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1778 <td class="left">A triple of three <tt>i32</tt> values</td>
1779 </tr><tr class="layout">
1780 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1781 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1782 second element is a <a href="#t_pointer">pointer</a> to a
1783 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1784 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1785 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1786</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1787
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1788</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1789
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1790<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1791<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1792</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1793
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1794<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1795
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1796<h5>Overview:</h5>
1797<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1798 together in memory. There is no padding between fields. Further, the
1799 alignment of a packed structure is 1 byte. The elements of a packed
1800 structure may be any type that has a size.</p>
1801
1802<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1803 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1804 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1805
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1806<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1807<pre>
1808 &lt; { &lt;type list&gt; } &gt;
1809</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1810
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1811<h5>Examples:</h5>
1812<table class="layout">
1813 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1814 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1815 <td class="left">A triple of three <tt>i32</tt> values</td>
1816 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1817 <td class="left">
1818<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1819 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1820 second element is a <a href="#t_pointer">pointer</a> to a
1821 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1822 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1823 </tr>
1824</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1825
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1826</div>
1827
1828<!-- _______________________________________________________________________ -->
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1829<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1830
1831<div class="doc_text">
1832
1833<h5>Overview:</h5>
1834<p>A union type describes an object with size and alignment suitable for
1835 an object of any one of a given set of types (also known as an "untagged"
1836 union). It is similar in concept and usage to a
1837 <a href="#t_struct">struct</a>, except that all members of the union
1838 have an offset of zero. The elements of a union may be any type that has a
1839 size. Unions must have at least one member - empty unions are not allowed.
1840 </p>
1841
1842<p>The size of the union as a whole will be the size of its largest member,
1843 and the alignment requirements of the union as a whole will be the largest
1844 alignment requirement of any member.</p>
1845
Dan Gohman1ad14992010-02-25 16:51:31 +0000[diff] [blame]1846<p>Union members are accessed using '<tt><a href="#i_load">load</a></tt> and
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1847 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1848 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1849 Since all members are at offset zero, the getelementptr instruction does
1850 not affect the address, only the type of the resulting pointer.</p>
1851
1852<h5>Syntax:</h5>
1853<pre>
1854 union { &lt;type list&gt; }
1855</pre>
1856
1857<h5>Examples:</h5>
1858<table class="layout">
1859 <tr class="layout">
1860 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1861 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1862 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1863 </tr><tr class="layout">
1864 <td class="left">
1865 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1866 <td class="left">A union, where the first element is a <tt>float</tt> and the
1867 second element is a <a href="#t_pointer">pointer</a> to a
1868 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1869 an <tt>i32</tt>.</td>
1870 </tr>
1871</table>
1872
1873</div>
1874
1875<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1876<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1877
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1878<div class="doc_text">
1879
1880<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1881<p>The pointer type is used to specify memory locations.
1882 Pointers are commonly used to reference objects in memory.</p>
1883
1884<p>Pointer types may have an optional address space attribute defining the
1885 numbered address space where the pointed-to object resides. The default
1886 address space is number zero. The semantics of non-zero address
1887 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1888
1889<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1890 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1891
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1892<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1893<pre>
1894 &lt;type&gt; *
1895</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1896
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1897<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1898<table class="layout">
1899 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1900 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1901 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1902 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1903 </tr>
1904 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]1905 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1906 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1907 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1908 <tt>i32</tt>.</td>
1909 </tr>
1910 <tr class="layout">
1911 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1912 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1913 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1914 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1915</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1916
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1917</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1918
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1919<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1920<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1921
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1922<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1923
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1924<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1925<p>A vector type is a simple derived type that represents a vector of elements.
1926 Vector types are used when multiple primitive data are operated in parallel
1927 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1928 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1929 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1930
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1931<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1932<pre>
1933 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1934</pre>
1935
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1936<p>The number of elements is a constant integer value; elementtype may be any
1937 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1938
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1939<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1940<table class="layout">
1941 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1942 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1943 <td class="left">Vector of 4 32-bit integer values.</td>
1944 </tr>
1945 <tr class="layout">
1946 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1947 <td class="left">Vector of 8 32-bit floating-point values.</td>
1948 </tr>
1949 <tr class="layout">
1950 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1951 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1952 </tr>
1953</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1954
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1955</div>
1956
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1957<!-- _______________________________________________________________________ -->
1958<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1959<div class="doc_text">
1960
1961<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1962<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1963 corresponds (for example) to the C notion of a forward declared structure
1964 type. In LLVM, opaque types can eventually be resolved to any type (not just
1965 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1966
1967<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1968<pre>
1969 opaque
1970</pre>
1971
1972<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1973<table class="layout">
1974 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1975 <td class="left"><tt>opaque</tt></td>
1976 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1977 </tr>
1978</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1979
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1980</div>
1981
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1982<!-- ======================================================================= -->
1983<div class="doc_subsection">
1984 <a name="t_uprefs">Type Up-references</a>
1985</div>
1986
1987<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1988
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1989<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1990<p>An "up reference" allows you to refer to a lexically enclosing type without
1991 requiring it to have a name. For instance, a structure declaration may
1992 contain a pointer to any of the types it is lexically a member of. Example
1993 of up references (with their equivalent as named type declarations)
1994 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1995
1996<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1997 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1998 { \2 }* %y = type { %y }*
1999 \1* %z = type %z*
2000</pre>
2001
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2002<p>An up reference is needed by the asmprinter for printing out cyclic types
2003 when there is no declared name for a type in the cycle. Because the
2004 asmprinter does not want to print out an infinite type string, it needs a
2005 syntax to handle recursive types that have no names (all names are optional
2006 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2007
2008<h5>Syntax:</h5>
2009<pre>
2010 \&lt;level&gt;
2011</pre>
2012
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2013<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]2014
2015<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2016<table class="layout">
2017 <tr class="layout">
2018 <td class="left"><tt>\1*</tt></td>
2019 <td class="left">Self-referential pointer.</td>
2020 </tr>
2021 <tr class="layout">
2022 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2023 <td class="left">Recursive structure where the upref refers to the out-most
2024 structure.</td>
2025 </tr>
2026</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2027
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2028</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2029
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2030<!-- *********************************************************************** -->
2031<div class="doc_section"> <a name="constants">Constants</a> </div>
2032<!-- *********************************************************************** -->
2033
2034<div class="doc_text">
2035
2036<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2037 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2038
2039</div>
2040
2041<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]2042<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2043
2044<div class="doc_text">
2045
2046<dl>
2047 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2048 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2049 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2050
2051 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2052 <dd>Standard integers (such as '4') are constants of
2053 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2054 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2055
2056 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2057 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2058 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2059 notation (see below). The assembler requires the exact decimal value of a
2060 floating-point constant. For example, the assembler accepts 1.25 but
2061 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2062 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2063
2064 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2065 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2066 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2067</dl>
2068
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2069<p>The one non-intuitive notation for constants is the hexadecimal form of
2070 floating point constants. For example, the form '<tt>double
2071 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2072 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2073 constants are required (and the only time that they are generated by the
2074 disassembler) is when a floating point constant must be emitted but it cannot
2075 be represented as a decimal floating point number in a reasonable number of
2076 digits. For example, NaN's, infinities, and other special values are
2077 represented in their IEEE hexadecimal format so that assembly and disassembly
2078 do not cause any bits to change in the constants.</p>
2079
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2080<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2081 represented using the 16-digit form shown above (which matches the IEEE754
2082 representation for double); float values must, however, be exactly
2083 representable as IEE754 single precision. Hexadecimal format is always used
2084 for long double, and there are three forms of long double. The 80-bit format
2085 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2086 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2087 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2088 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2089 currently supported target uses this format. Long doubles will only work if
2090 they match the long double format on your target. All hexadecimal formats
2091 are big-endian (sign bit at the left).</p>
2092
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2093</div>
2094
2095<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2096<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2097<a name="aggregateconstants"></a> <!-- old anchor -->
2098<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2099</div>
2100
2101<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2102
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2103<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2104 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2105
2106<dl>
2107 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2108 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2109 type definitions (a comma separated list of elements, surrounded by braces
2110 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2111 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2112 Structure constants must have <a href="#t_struct">structure type</a>, and
2113 the number and types of elements must match those specified by the
2114 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2115
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2116 <dt><b>Union constants</b></dt>
2117 <dd>Union constants are represented with notation similar to a structure with
2118 a single element - that is, a single typed element surrounded
2119 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2120 <a href="#t_union">union type</a> can be initialized with a single-element
2121 struct as long as the type of the struct element matches the type of
2122 one of the union members.</dd>
2123
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2124 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2125 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2126 definitions (a comma separated list of elements, surrounded by square
2127 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2128 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2129 the number and types of elements must match those specified by the
2130 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2131
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2132 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2133 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2134 definitions (a comma separated list of elements, surrounded by
2135 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2136 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2137 have <a href="#t_vector">vector type</a>, and the number and types of
2138 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2139
2140 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2141 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2142 value to zero of <em>any</em> type, including scalar and
2143 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2144 This is often used to avoid having to print large zero initializers
2145 (e.g. for large arrays) and is always exactly equivalent to using explicit
2146 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2147
2148 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2149 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2150 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2151 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2152 be interpreted as part of the instruction stream, metadata is a place to
2153 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2154</dl>
2155
2156</div>
2157
2158<!-- ======================================================================= -->
2159<div class="doc_subsection">
2160 <a name="globalconstants">Global Variable and Function Addresses</a>
2161</div>
2162
2163<div class="doc_text">
2164
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2165<p>The addresses of <a href="#globalvars">global variables</a>
2166 and <a href="#functionstructure">functions</a> are always implicitly valid
2167 (link-time) constants. These constants are explicitly referenced when
2168 the <a href="#identifiers">identifier for the global</a> is used and always
2169 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2170 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2171
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2172<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2173<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2174@X = global i32 17
2175@Y = global i32 42
2176@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2177</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2178</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2179
2180</div>
2181
2182<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2183<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2184<div class="doc_text">
2185
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2186<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]2187 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2188 Undefined values may be of any type (other than label or void) and be used
2189 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2190
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2191<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2192 program is well defined no matter what value is used. This gives the
2193 compiler more freedom to optimize. Here are some examples of (potentially
2194 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2195
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2196
2197<div class="doc_code">
2198<pre>
2199 %A = add %X, undef
2200 %B = sub %X, undef
2201 %C = xor %X, undef
2202Safe:
2203 %A = undef
2204 %B = undef
2205 %C = undef
2206</pre>
2207</div>
2208
2209<p>This is safe because all of the output bits are affected by the undef bits.
2210Any output bit can have a zero or one depending on the input bits.</p>
2211
2212<div class="doc_code">
2213<pre>
2214 %A = or %X, undef
2215 %B = and %X, undef
2216Safe:
2217 %A = -1
2218 %B = 0
2219Unsafe:
2220 %A = undef
2221 %B = undef
2222</pre>
2223</div>
2224
2225<p>These logical operations have bits that are not always affected by the input.
2226For example, if "%X" has a zero bit, then the output of the 'and' operation will
2227always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2228such, 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]2229However, it is safe to assume that all bits of the undef could be 0, and
2230optimize the and to 0. Likewise, it is safe to assume that all the bits of
2231the 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]2232-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2233
2234<div class="doc_code">
2235<pre>
2236 %A = select undef, %X, %Y
2237 %B = select undef, 42, %Y
2238 %C = select %X, %Y, undef
2239Safe:
2240 %A = %X (or %Y)
2241 %B = 42 (or %Y)
2242 %C = %Y
2243Unsafe:
2244 %A = undef
2245 %B = undef
2246 %C = undef
2247</pre>
2248</div>
2249
2250<p>This set of examples show that undefined select (and conditional branch)
2251conditions can go "either way" but they have to come from one of the two
2252operands. In the %A example, if %X and %Y were both known to have a clear low
2253bit, then %A would have to have a cleared low bit. However, in the %C example,
2254the optimizer is allowed to assume that the undef operand could be the same as
2255%Y, allowing the whole select to be eliminated.</p>
2256
2257
2258<div class="doc_code">
2259<pre>
2260 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2261
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2262 %B = undef
2263 %C = xor %B, %B
2264
2265 %D = undef
2266 %E = icmp lt %D, 4
2267 %F = icmp gte %D, 4
2268
2269Safe:
2270 %A = undef
2271 %B = undef
2272 %C = undef
2273 %D = undef
2274 %E = undef
2275 %F = undef
2276</pre>
2277</div>
2278
2279<p>This example points out that two undef operands are not necessarily the same.
2280This can be surprising to people (and also matches C semantics) where they
2281assume that "X^X" is always zero, even if X is undef. This isn't true for a
2282number of reasons, but the short answer is that an undef "variable" can
2283arbitrarily change its value over its "live range". This is true because the
2284"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2285logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2286so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2287to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2288would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2289
2290<div class="doc_code">
2291<pre>
2292 %A = fdiv undef, %X
2293 %B = fdiv %X, undef
2294Safe:
2295 %A = undef
2296b: unreachable
2297</pre>
2298</div>
2299
2300<p>These examples show the crucial difference between an <em>undefined
2301value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2302allowed to have an arbitrary bit-pattern. This means that the %A operation
2303can be constant folded to undef because the undef could be an SNaN, and fdiv is
2304not (currently) defined on SNaN's. However, in the second example, we can make
2305a more aggressive assumption: because the undef is allowed to be an arbitrary
2306value, 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]2307has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2308does not execute at all. This allows us to delete the divide and all code after
2309it: since the undefined operation "can't happen", the optimizer can assume that
2310it occurs in dead code.
2311</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2312
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2313<div class="doc_code">
2314<pre>
2315a: store undef -> %X
2316b: store %X -> undef
2317Safe:
2318a: &lt;deleted&gt;
2319b: unreachable
2320</pre>
2321</div>
2322
2323<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2324can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2325overwritten with bits that happen to match what was already there. However, a
2326store "to" an undefined location could clobber arbitrary memory, therefore, it
2327has undefined behavior.</p>
2328
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2329</div>
2330
2331<!-- ======================================================================= -->
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2332<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2333<div class="doc_text">
2334
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2335<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2336 instead of representing an unspecified bit pattern, they represent the
2337 fact that an instruction or constant expression which cannot evoke side
2338 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2339 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2340
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2341<p>There is currently no way of representing a trap value in the IR; they
Dan Gohmanac355aa2010-05-03 14:51:43 +0000[diff] [blame]2342 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2343 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2344
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2345<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2346
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2347<p>
2348<ul>
2349<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2350 their operands.</li>
2351
2352<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2353 to their dynamic predecessor basic block.</li>
2354
2355<li>Function arguments depend on the corresponding actual argument values in
2356 the dynamic callers of their functions.</li>
2357
2358<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2359 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2360 control back to them.</li>
2361
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2362<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2363 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2364 or exception-throwing call instructions that dynamically transfer control
2365 back to them.</li>
2366
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2367<li>Non-volatile loads and stores depend on the most recent stores to all of the
2368 referenced memory addresses, following the order in the IR
2369 (including loads and stores implied by intrinsics such as
2370 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2371
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2372<!-- TODO: In the case of multiple threads, this only applies if the store
2373 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2374
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2375<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2376
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2377<li>An instruction with externally visible side effects depends on the most
2378 recent preceding instruction with externally visible side effects, following
2379 the order in the IR. (This includes volatile loads and stores.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2380
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2381<li>An instruction <i>control-depends</i> on a
2382 <a href="#terminators">terminator instruction</a>
2383 if the terminator instruction has multiple successors and the instruction
2384 is always executed when control transfers to one of the successors, and
2385 may not be executed when control is transfered to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2386
2387<li>Dependence is transitive.</li>
2388
2389</ul>
2390</p>
2391
2392<p>Whenever a trap value is generated, all values which depend on it evaluate
2393 to trap. If they have side effects, the evoke their side effects as if each
2394 operand with a trap value were undef. If they have externally-visible side
2395 effects, the behavior is undefined.</p>
2396
2397<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2398
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2399<div class="doc_code">
2400<pre>
2401entry:
2402 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2403 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2404 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2405 store i32 0, i32* %trap_yet_again ; undefined behavior
2406
2407 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2408 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2409
2410 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2411
2412 %narrowaddr = bitcast i32* @g to i16*
2413 %wideaddr = bitcast i32* @g to i64*
2414 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2415 %trap4 = load i64* %widaddr ; Returns a trap value.
2416
2417 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2418 %br i1 %cmp, %true, %end ; Branch to either destination.
2419
2420true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2421 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2422 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2423 br label %end
2424
2425end:
2426 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2427 ; Both edges into this PHI are
2428 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2429 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2430
2431 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2432 ; so this is defined (ignoring earlier
2433 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2434</pre>
2435</div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2436
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2437</div>
2438
2439<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2440<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2441 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2442<div class="doc_text">
2443
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2444<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2445
2446<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2447 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2448 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2449
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2450<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2451 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2452 against null. Pointer equality tests between labels addresses is undefined
2453 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2454 equal to the null pointer. This may also be passed around as an opaque
2455 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2456 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2457 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2458
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2459<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2460 using the value as the operand to an inline assembly, but that is target
2461 specific.
2462 </p>
2463
2464</div>
2465
2466
2467<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2468<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2469</div>
2470
2471<div class="doc_text">
2472
2473<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2474 to be used as constants. Constant expressions may be of
2475 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2476 operation that does not have side effects (e.g. load and call are not
2477 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2478
2479<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2480 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2481 <dd>Truncate a constant to another type. The bit size of CST must be larger
2482 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2483
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2484 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2485 <dd>Zero extend a constant to another type. The bit size of CST must be
2486 smaller or equal to the bit size of TYPE. Both types must be
2487 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2488
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2489 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2490 <dd>Sign extend a constant to another type. The bit size of CST must be
2491 smaller or equal to the bit size of TYPE. Both types must be
2492 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2493
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2494 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2495 <dd>Truncate a floating point constant to another floating point type. The
2496 size of CST must be larger than the size of TYPE. Both types must be
2497 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2498
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2499 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2500 <dd>Floating point extend a constant to another type. The size of CST must be
2501 smaller or equal to the size of TYPE. Both types must be floating
2502 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2503
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2504 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2505 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2506 constant. TYPE must be a scalar or vector integer type. CST must be of
2507 scalar or vector floating point type. Both CST and TYPE must be scalars,
2508 or vectors of the same number of elements. If the value won't fit in the
2509 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2510
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2511 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2512 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2513 constant. TYPE must be a scalar or vector integer type. CST must be of
2514 scalar or vector floating point type. Both CST and TYPE must be scalars,
2515 or vectors of the same number of elements. If the value won't fit in the
2516 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2517
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2518 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2519 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2520 constant. TYPE must be a scalar or vector floating point type. CST must be
2521 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2522 vectors of the same number of elements. If the value won't fit in the
2523 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2524
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2525 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2526 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2527 constant. TYPE must be a scalar or vector floating point type. CST must be
2528 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2529 vectors of the same number of elements. If the value won't fit in the
2530 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2531
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2532 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2533 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2534 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2535 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2536 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2537
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2538 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2539 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2540 type. CST must be of integer type. The CST value is zero extended,
2541 truncated, or unchanged to make it fit in a pointer size. This one is
2542 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2543
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2544 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2545 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2546 are the same as those for the <a href="#i_bitcast">bitcast
2547 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2548
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2549 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2550 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2551 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2552 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2553 instruction, the index list may have zero or more indexes, which are
2554 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2555
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2556 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2557 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2558
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2559 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2560 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2561
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2562 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2563 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2564
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2565 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2566 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2567 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2568
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2569 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2570 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2571 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2572
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2573 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2574 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2575 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2576
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2577 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2578 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2579 constants. The index list is interpreted in a similar manner as indices in
2580 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2581 index value must be specified.</dd>
2582
2583 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2584 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2585 constants. The index list is interpreted in a similar manner as indices in
2586 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2587 index value must be specified.</dd>
2588
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2589 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2590 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2591 be any of the <a href="#binaryops">binary</a>
2592 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2593 on operands are the same as those for the corresponding instruction
2594 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2595</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2596
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2597</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2598
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2599<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2600<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2601<!-- *********************************************************************** -->
2602
2603<!-- ======================================================================= -->
2604<div class="doc_subsection">
2605<a name="inlineasm">Inline Assembler Expressions</a>
2606</div>
2607
2608<div class="doc_text">
2609
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2610<p>LLVM supports inline assembler expressions (as opposed
2611 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2612 a special value. This value represents the inline assembler as a string
2613 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2614 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2615 expression has side effects, and a flag indicating whether the function
2616 containing the asm needs to align its stack conservatively. An example
2617 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2618
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2619<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2620<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2621i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2622</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2623</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2624
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2625<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2626 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2627 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2628
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2629<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2630<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2631%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]2632</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2633</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2634
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2635<p>Inline asms with side effects not visible in the constraint list must be
2636 marked as having side effects. This is done through the use of the
2637 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2638
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2639<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2640<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2641call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2642</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2643</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2644
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2645<p>In some cases inline asms will contain code that will not work unless the
2646 stack is aligned in some way, such as calls or SSE instructions on x86,
2647 yet will not contain code that does that alignment within the asm.
2648 The compiler should make conservative assumptions about what the asm might
2649 contain and should generate its usual stack alignment code in the prologue
2650 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2651
2652<div class="doc_code">
2653<pre>
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2654call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2655</pre>
2656</div>
2657
2658<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2659 first.</p>
2660
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2661<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2662 documented here. Constraints on what can be done (e.g. duplication, moving,
2663 etc need to be documented). This is probably best done by reference to
2664 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2665</div>
2666
2667<div class="doc_subsubsection">
2668<a name="inlineasm_md">Inline Asm Metadata</a>
2669</div>
2670
2671<div class="doc_text">
2672
2673<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2674 attached to it that contains a constant integer. If present, the code
2675 generator will use the integer as the location cookie value when report
2676 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2677 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2678 source code that produced it. For example:</p>
2679
2680<div class="doc_code">
2681<pre>
2682call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2683...
2684!42 = !{ i32 1234567 }
2685</pre>
2686</div>
2687
2688<p>It is up to the front-end to make sense of the magic numbers it places in the
2689 IR.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2690
2691</div>
2692
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2693<!-- ======================================================================= -->
2694<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2695 Strings</a>
2696</div>
2697
2698<div class="doc_text">
2699
2700<p>LLVM IR allows metadata to be attached to instructions in the program that
2701 can convey extra information about the code to the optimizers and code
2702 generator. One example application of metadata is source-level debug
2703 information. There are two metadata primitives: strings and nodes. All
2704 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2705 preceding exclamation point ('<tt>!</tt>').</p>
2706
2707<p>A metadata string is a string surrounded by double quotes. It can contain
2708 any character by escaping non-printable characters with "\xx" where "xx" is
2709 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2710
2711<p>Metadata nodes are represented with notation similar to structure constants
2712 (a comma separated list of elements, surrounded by braces and preceded by an
2713 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2714 10}</tt>". Metadata nodes can have any values as their operand.</p>
2715
2716<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2717 metadata nodes, which can be looked up in the module symbol table. For
2718 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2719
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2720<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2721 function is using two metadata arguments.
2722
2723 <div class="doc_code">
2724 <pre>
2725 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2726 </pre>
2727 </div></p>
2728
2729<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2730 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2731
2732 <div class="doc_code">
2733 <pre>
2734 %indvar.next = add i64 %indvar, 1, !dbg !21
2735 </pre>
2736 </div></p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2737</div>
2738
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2739
2740<!-- *********************************************************************** -->
2741<div class="doc_section">
2742 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2743</div>
2744<!-- *********************************************************************** -->
2745
2746<p>LLVM has a number of "magic" global variables that contain data that affect
2747code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2748of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2749section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2750by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2751
2752<!-- ======================================================================= -->
2753<div class="doc_subsection">
2754<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2755</div>
2756
2757<div class="doc_text">
2758
2759<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2760href="#linkage_appending">appending linkage</a>. This array contains a list of
2761pointers to global variables and functions which may optionally have a pointer
2762cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2763
2764<pre>
2765 @X = global i8 4
2766 @Y = global i32 123
2767
2768 @llvm.used = appending global [2 x i8*] [
2769 i8* @X,
2770 i8* bitcast (i32* @Y to i8*)
2771 ], section "llvm.metadata"
2772</pre>
2773
2774<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2775compiler, assembler, and linker are required to treat the symbol as if there is
2776a reference to the global that it cannot see. For example, if a variable has
2777internal linkage and no references other than that from the <tt>@llvm.used</tt>
2778list, it cannot be deleted. This is commonly used to represent references from
2779inline asms and other things the compiler cannot "see", and corresponds to
2780"attribute((used))" in GNU C.</p>
2781
2782<p>On some targets, the code generator must emit a directive to the assembler or
2783object file to prevent the assembler and linker from molesting the symbol.</p>
2784
2785</div>
2786
2787<!-- ======================================================================= -->
2788<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2789<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2790</div>
2791
2792<div class="doc_text">
2793
2794<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2795<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2796touching the symbol. On targets that support it, this allows an intelligent
2797linker to optimize references to the symbol without being impeded as it would be
2798by <tt>@llvm.used</tt>.</p>
2799
2800<p>This is a rare construct that should only be used in rare circumstances, and
2801should not be exposed to source languages.</p>
2802
2803</div>
2804
2805<!-- ======================================================================= -->
2806<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2807<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2808</div>
2809
2810<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2811<pre>
2812%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2813@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2814</pre>
2815<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
2816</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2817
2818</div>
2819
2820<!-- ======================================================================= -->
2821<div class="doc_subsection">
2822<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2823</div>
2824
2825<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2826<pre>
2827%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2828@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2829</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2830
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2831<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
2832</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2833
2834</div>
2835
2836
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2837<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2838<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2839<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2840
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2841<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2842
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2843<p>The LLVM instruction set consists of several different classifications of
2844 instructions: <a href="#terminators">terminator
2845 instructions</a>, <a href="#binaryops">binary instructions</a>,
2846 <a href="#bitwiseops">bitwise binary instructions</a>,
2847 <a href="#memoryops">memory instructions</a>, and
2848 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2849
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2850</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2851
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2852<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2853<div class="doc_subsection"> <a name="terminators">Terminator
2854Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2855
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2856<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2857
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2858<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2859 in a program ends with a "Terminator" instruction, which indicates which
2860 block should be executed after the current block is finished. These
2861 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2862 control flow, not values (the one exception being the
2863 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2864
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2865<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2866 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2867 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2868 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2869 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2870 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2871 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2872 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2873
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2874</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2875
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2876<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2877<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2878Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2879
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2880<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2881
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2882<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2883<pre>
2884 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]2885 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2886</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2887
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2888<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2889<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2890 a value) from a function back to the caller.</p>
2891
2892<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2893 value and then causes control flow, and one that just causes control flow to
2894 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2895
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2897<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2898 return value. The type of the return value must be a
2899 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2900
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2901<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2902 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2903 value or a return value with a type that does not match its type, or if it
2904 has a void return type and contains a '<tt>ret</tt>' instruction with a
2905 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2906
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2907<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2908<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2909 the calling function's context. If the caller is a
2910 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2911 instruction after the call. If the caller was an
2912 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2913 the beginning of the "normal" destination block. If the instruction returns
2914 a value, that value shall set the call or invoke instruction's return
2915 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2916
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2917<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2918<pre>
2919 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2920 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2921 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]2922</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2923
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2924</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2925<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2926<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2927
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2928<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2929
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2930<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2931<pre>
2932 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]2933</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2934
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2935<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2936<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2937 different basic block in the current function. There are two forms of this
2938 instruction, corresponding to a conditional branch and an unconditional
2939 branch.</p>
2940
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2941<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2942<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2943 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2944 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2945 target.</p>
2946
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2947<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2948<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2949 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2950 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2951 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2952
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2953<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2954<pre>
2955Test:
2956 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2957 br i1 %cond, label %IfEqual, label %IfUnequal
2958IfEqual:
2959 <a href="#i_ret">ret</a> i32 1
2960IfUnequal:
2961 <a href="#i_ret">ret</a> i32 0
2962</pre>
2963
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2964</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2965
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2966<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2967<div class="doc_subsubsection">
2968 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2969</div>
2970
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2971<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2972
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2973<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2974<pre>
2975 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2976</pre>
2977
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2978<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2979<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]2980 several different places. It is a generalization of the '<tt>br</tt>'
2981 instruction, allowing a branch to occur to one of many possible
2982 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2983
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2984<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2985<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2986 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2987 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2988 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2989
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2990<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2991<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2992 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2993 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2994 transferred to the corresponding destination; otherwise, control flow is
2995 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2996
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2997<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2998<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2999 <tt>switch</tt> instruction, this instruction may be code generated in
3000 different ways. For example, it could be generated as a series of chained
3001 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3002
3003<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3004<pre>
3005 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3006 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3007 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3008
3009 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3010 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3011
3012 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3013 switch i32 %val, label %otherwise [ i32 0, label %onzero
3014 i32 1, label %onone
3015 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3016</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3017
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3018</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3019
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3020
3021<!-- _______________________________________________________________________ -->
3022<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3023 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3024</div>
3025
3026<div class="doc_text">
3027
3028<h5>Syntax:</h5>
3029<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3030 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]3031</pre>
3032
3033<h5>Overview:</h5>
3034
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3035<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3036 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3037 "<tt>address</tt>". Address must be derived from a <a
3038 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3039
3040<h5>Arguments:</h5>
3041
3042<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3043 rest of the arguments indicate the full set of possible destinations that the
3044 address may point to. Blocks are allowed to occur multiple times in the
3045 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3046
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3047<p>This destination list is required so that dataflow analysis has an accurate
3048 understanding of the CFG.</p>
3049
3050<h5>Semantics:</h5>
3051
3052<p>Control transfers to the block specified in the address argument. All
3053 possible destination blocks must be listed in the label list, otherwise this
3054 instruction has undefined behavior. This implies that jumps to labels
3055 defined in other functions have undefined behavior as well.</p>
3056
3057<h5>Implementation:</h5>
3058
3059<p>This is typically implemented with a jump through a register.</p>
3060
3061<h5>Example:</h5>
3062<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3063 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3064</pre>
3065
3066</div>
3067
3068
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3069<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3070<div class="doc_subsubsection">
3071 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3072</div>
3073
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3074<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3075
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3076<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3077<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3078 &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]3079 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3080</pre>
3081
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3082<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3083<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3084 function, with the possibility of control flow transfer to either the
3085 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3086 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3087 control flow will return to the "normal" label. If the callee (or any
3088 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3089 instruction, control is interrupted and continued at the dynamically nearest
3090 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3091
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3092<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3093<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3094
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3095<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3096 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3097 convention</a> the call should use. If none is specified, the call
3098 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3099
3100 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3101 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3102 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3103
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3104 <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]3105 function value being invoked. In most cases, this is a direct function
3106 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3107 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3108
3109 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3110 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3111
3112 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3113 signature argument types and parameter attributes. All arguments must be
3114 of <a href="#t_firstclass">first class</a> type. If the function
3115 signature indicates the function accepts a variable number of arguments,
3116 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3117
3118 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3119 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3120
3121 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3122 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3123
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3124 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3125 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3126 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3127</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3128
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3129<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3130<p>This instruction is designed to operate as a standard
3131 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3132 primary difference is that it establishes an association with a label, which
3133 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3134
3135<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3136 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3137 exception. Additionally, this is important for implementation of
3138 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3139
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3140<p>For the purposes of the SSA form, the definition of the value returned by the
3141 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3142 block to the "normal" label. If the callee unwinds then no return value is
3143 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3144
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3145<p>Note that the code generator does not yet completely support unwind, and
3146that the invoke/unwind semantics are likely to change in future versions.</p>
3147
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3148<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3149<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3150 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3151 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3152 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3153 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3154</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3155
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3156</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3157
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3158<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3159
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3160<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3161Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3162
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3163<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3164
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3165<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3166<pre>
3167 unwind
3168</pre>
3169
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3170<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3171<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3172 at the first callee in the dynamic call stack which used
3173 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3174 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3175
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3176<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3177<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3178 immediately halt. The dynamic call stack is then searched for the
3179 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3180 Once found, execution continues at the "exceptional" destination block
3181 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3182 instruction in the dynamic call chain, undefined behavior results.</p>
3183
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3184<p>Note that the code generator does not yet completely support unwind, and
3185that the invoke/unwind semantics are likely to change in future versions.</p>
3186
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3187</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3188
3189<!-- _______________________________________________________________________ -->
3190
3191<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3192Instruction</a> </div>
3193
3194<div class="doc_text">
3195
3196<h5>Syntax:</h5>
3197<pre>
3198 unreachable
3199</pre>
3200
3201<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3202<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3203 instruction is used to inform the optimizer that a particular portion of the
3204 code is not reachable. This can be used to indicate that the code after a
3205 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3206
3207<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3208<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3209
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3210</div>
3211
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3212<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3213<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3214
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3215<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3216
3217<p>Binary operators are used to do most of the computation in a program. They
3218 require two operands of the same type, execute an operation on them, and
3219 produce a single value. The operands might represent multiple data, as is
3220 the case with the <a href="#t_vector">vector</a> data type. The result value
3221 has the same type as its operands.</p>
3222
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3223<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3224
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3225</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3226
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3227<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3228<div class="doc_subsubsection">
3229 <a name="i_add">'<tt>add</tt>' Instruction</a>
3230</div>
3231
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3232<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3233
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3234<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3235<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3236 &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]3237 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3238 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3239 &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]3240</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3241
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3242<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3243<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3244
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3245<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3246<p>The two arguments to the '<tt>add</tt>' instruction must
3247 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3248 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3249
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3250<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3251<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3252
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3253<p>If the sum has unsigned overflow, the result returned is the mathematical
3254 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]3255
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3256<p>Because LLVM integers use a two's complement representation, this instruction
3257 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3258
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3259<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3260 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3261 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3262 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3263 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3264
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3265<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3266<pre>
3267 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3268</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3269
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3270</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3271
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3272<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3273<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3274 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3275</div>
3276
3277<div class="doc_text">
3278
3279<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3280<pre>
3281 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3282</pre>
3283
3284<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3285<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3286
3287<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3288<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3289 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3290 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3291
3292<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3293<p>The value produced is the floating point sum of the two operands.</p>
3294
3295<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3296<pre>
3297 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3298</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3299
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3300</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3301
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3302<!-- _______________________________________________________________________ -->
3303<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3304 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3305</div>
3306
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3307<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3308
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3309<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3310<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3311 &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]3312 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3313 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3314 &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]3315</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3316
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3317<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3318<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3319 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3320
3321<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3322 '<tt>neg</tt>' instruction present in most other intermediate
3323 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3324
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3325<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3326<p>The two arguments to the '<tt>sub</tt>' instruction must
3327 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3328 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3329
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3330<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3331<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3332
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3333<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3334 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3335 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3336
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3337<p>Because LLVM integers use a two's complement representation, this instruction
3338 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3339
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3340<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3341 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3342 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3343 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3344 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3345
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3346<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3347<pre>
3348 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3349 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3350</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3351
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3352</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3353
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3354<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3355<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3356 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3357</div>
3358
3359<div class="doc_text">
3360
3361<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3362<pre>
3363 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3364</pre>
3365
3366<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3367<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3368 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3369
3370<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3371 '<tt>fneg</tt>' instruction present in most other intermediate
3372 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3373
3374<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3375<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3376 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3377 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3378
3379<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3380<p>The value produced is the floating point difference of the two operands.</p>
3381
3382<h5>Example:</h5>
3383<pre>
3384 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3385 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3386</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3387
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3388</div>
3389
3390<!-- _______________________________________________________________________ -->
3391<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3392 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3393</div>
3394
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3395<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3396
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3397<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3398<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3399 &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]3400 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3401 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3402 &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]3403</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3404
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3405<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3406<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3407
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3408<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3409<p>The two arguments to the '<tt>mul</tt>' instruction must
3410 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3411 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3412
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3413<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3414<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3415
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3416<p>If the result of the multiplication has unsigned overflow, the result
3417 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3418 width of the result.</p>
3419
3420<p>Because LLVM integers use a two's complement representation, and the result
3421 is the same width as the operands, this instruction returns the correct
3422 result for both signed and unsigned integers. If a full product
3423 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3424 be sign-extended or zero-extended as appropriate to the width of the full
3425 product.</p>
3426
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3427<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3428 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3429 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3430 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3431 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3432
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3433<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3434<pre>
3435 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3436</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3437
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3438</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3439
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3440<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3441<div class="doc_subsubsection">
3442 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3443</div>
3444
3445<div class="doc_text">
3446
3447<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3448<pre>
3449 &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]3450</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3451
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3452<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3453<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3454
3455<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3456<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3457 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3458 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3459
3460<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3461<p>The value produced is the floating point product of the two operands.</p>
3462
3463<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3464<pre>
3465 &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]3466</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3467
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3468</div>
3469
3470<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3471<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3472</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3473
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3474<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3475
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3476<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3477<pre>
3478 &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]3479</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3480
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3481<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3482<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3483
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3484<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3485<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3486 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3487 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3488
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3489<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3490<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3491
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3492<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3493 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3494
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3495<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3496
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3497<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3498<pre>
3499 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3500</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3501
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3502</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3503
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3504<!-- _______________________________________________________________________ -->
3505<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3506</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3507
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3508<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3509
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3510<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3511<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3512 &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]3513 &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]3514</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3515
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3516<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3517<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3518
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3519<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3520<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3521 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3522 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3523
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3524<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3525<p>The value produced is the signed integer quotient of the two operands rounded
3526 towards zero.</p>
3527
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3528<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3529 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3530
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3531<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3532 undefined behavior; this is a rare case, but can occur, for example, by doing
3533 a 32-bit division of -2147483648 by -1.</p>
3534
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3535<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3536 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3537 be rounded or if overflow would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3538
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3539<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3540<pre>
3541 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3542</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3543
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3544</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3545
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3546<!-- _______________________________________________________________________ -->
3547<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3548Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3549
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3550<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3551
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3552<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3553<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3554 &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]3555</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3556
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3557<h5>Overview:</h5>
3558<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3559
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3560<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3561<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3562 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3563 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3564
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3565<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3566<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3567
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3568<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3569<pre>
3570 &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]3571</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3572
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3573</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3574
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3575<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3576<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3577</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3578
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3579<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3580
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3581<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3582<pre>
3583 &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]3584</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3585
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3586<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3587<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3588 division of its two arguments.</p>
3589
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3590<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3591<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3592 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3593 values. Both arguments must have identical types.</p>
3594
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3595<h5>Semantics:</h5>
3596<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3597 This instruction always performs an unsigned division to get the
3598 remainder.</p>
3599
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3600<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3601 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3602
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3603<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3604
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3605<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3606<pre>
3607 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3608</pre>
3609
3610</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3611
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3612<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3613<div class="doc_subsubsection">
3614 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3615</div>
3616
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3617<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3618
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3619<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3620<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3621 &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]3622</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3623
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3624<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3625<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3626 division of its two operands. This instruction can also take
3627 <a href="#t_vector">vector</a> versions of the values in which case the
3628 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3629
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3630<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3631<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3632 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3633 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3634
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3635<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3636<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3637 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3638 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3639 a value. For more information about the difference,
3640 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3641 Math Forum</a>. For a table of how this is implemented in various languages,
3642 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3643 Wikipedia: modulo operation</a>.</p>
3644
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3645<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3646 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3647
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3648<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3649 Overflow also leads to undefined behavior; this is a rare case, but can
3650 occur, for example, by taking the remainder of a 32-bit division of
3651 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3652 lets srem be implemented using instructions that return both the result of
3653 the division and the remainder.)</p>
3654
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3655<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3656<pre>
3657 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3658</pre>
3659
3660</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3661
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3662<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3663<div class="doc_subsubsection">
3664 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3665
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3666<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3667
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3668<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3669<pre>
3670 &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]3671</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3672
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3673<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3674<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3675 its two operands.</p>
3676
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3677<h5>Arguments:</h5>
3678<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3679 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3680 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3681
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3682<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3683<p>This instruction returns the <i>remainder</i> of a division. The remainder
3684 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3685
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3686<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3687<pre>
3688 &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]3689</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3690
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3691</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3692
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3693<!-- ======================================================================= -->
3694<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3695Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3696
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3697<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3698
3699<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3700 program. They are generally very efficient instructions and can commonly be
3701 strength reduced from other instructions. They require two operands of the
3702 same type, execute an operation on them, and produce a single value. The
3703 resulting value is the same type as its operands.</p>
3704
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3705</div>
3706
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3707<!-- _______________________________________________________________________ -->
3708<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3709Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3710
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3711<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3712
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3713<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3714<pre>
3715 &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]3716</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3717
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3718<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3719<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3720 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3721
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3722<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3723<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3724 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3725 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3726
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3727<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3728<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3729 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3730 is (statically or dynamically) negative or equal to or larger than the number
3731 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3732 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3733 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3734
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3735<h5>Example:</h5>
3736<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3737 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3738 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3739 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3740 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3741 &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]3742</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3743
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3744</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3745
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3746<!-- _______________________________________________________________________ -->
3747<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3748Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3749
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3750<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3751
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3752<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3753<pre>
3754 &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]3755</pre>
3756
3757<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3758<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3759 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3760
3761<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3762<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3763 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3764 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3765
3766<h5>Semantics:</h5>
3767<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3768 significant bits of the result will be filled with zero bits after the shift.
3769 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3770 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3771 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3772 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3773
3774<h5>Example:</h5>
3775<pre>
3776 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3777 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3778 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3779 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3780 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3781 &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]3782</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3783
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3784</div>
3785
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3786<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3787<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3788Instruction</a> </div>
3789<div class="doc_text">
3790
3791<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3792<pre>
3793 &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]3794</pre>
3795
3796<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3797<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3798 operand shifted to the right a specified number of bits with sign
3799 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3800
3801<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3802<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3803 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3804 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3805
3806<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3807<p>This instruction always performs an arithmetic shift right operation, The
3808 most significant bits of the result will be filled with the sign bit
3809 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3810 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3811 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3812 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3813
3814<h5>Example:</h5>
3815<pre>
3816 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3817 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3818 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3819 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3820 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3821 &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]3822</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3823
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3824</div>
3825
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3826<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3827<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3828Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3829
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3830<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3831
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3832<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3833<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3834 &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]3835</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3836
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3837<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3838<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3839 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3840
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3841<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3842<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3843 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3844 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3845
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3846<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3847<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3848
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3849<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3850 <tbody>
3851 <tr>
3852 <td>In0</td>
3853 <td>In1</td>
3854 <td>Out</td>
3855 </tr>
3856 <tr>
3857 <td>0</td>
3858 <td>0</td>
3859 <td>0</td>
3860 </tr>
3861 <tr>
3862 <td>0</td>
3863 <td>1</td>
3864 <td>0</td>
3865 </tr>
3866 <tr>
3867 <td>1</td>
3868 <td>0</td>
3869 <td>0</td>
3870 </tr>
3871 <tr>
3872 <td>1</td>
3873 <td>1</td>
3874 <td>1</td>
3875 </tr>
3876 </tbody>
3877</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3878
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3879<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3880<pre>
3881 &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]3882 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3883 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3884</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3885</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3886<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3887<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3888
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3889<div class="doc_text">
3890
3891<h5>Syntax:</h5>
3892<pre>
3893 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3894</pre>
3895
3896<h5>Overview:</h5>
3897<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3898 two operands.</p>
3899
3900<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3901<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3902 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3903 values. Both arguments must have identical types.</p>
3904
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3905<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3906<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3907
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3908<table border="1" cellspacing="0" cellpadding="4">
3909 <tbody>
3910 <tr>
3911 <td>In0</td>
3912 <td>In1</td>
3913 <td>Out</td>
3914 </tr>
3915 <tr>
3916 <td>0</td>
3917 <td>0</td>
3918 <td>0</td>
3919 </tr>
3920 <tr>
3921 <td>0</td>
3922 <td>1</td>
3923 <td>1</td>
3924 </tr>
3925 <tr>
3926 <td>1</td>
3927 <td>0</td>
3928 <td>1</td>
3929 </tr>
3930 <tr>
3931 <td>1</td>
3932 <td>1</td>
3933 <td>1</td>
3934 </tr>
3935 </tbody>
3936</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3937
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3938<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3939<pre>
3940 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3941 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3942 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3943</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3944
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3945</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3946
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3947<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3948<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3949Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3950
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3951<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3952
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3953<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3954<pre>
3955 &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]3956</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3957
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3958<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3959<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3960 its two operands. The <tt>xor</tt> is used to implement the "one's
3961 complement" operation, which is the "~" operator in C.</p>
3962
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3963<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3964<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3965 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3966 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3967
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3968<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3969<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3970
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3971<table border="1" cellspacing="0" cellpadding="4">
3972 <tbody>
3973 <tr>
3974 <td>In0</td>
3975 <td>In1</td>
3976 <td>Out</td>
3977 </tr>
3978 <tr>
3979 <td>0</td>
3980 <td>0</td>
3981 <td>0</td>
3982 </tr>
3983 <tr>
3984 <td>0</td>
3985 <td>1</td>
3986 <td>1</td>
3987 </tr>
3988 <tr>
3989 <td>1</td>
3990 <td>0</td>
3991 <td>1</td>
3992 </tr>
3993 <tr>
3994 <td>1</td>
3995 <td>1</td>
3996 <td>0</td>
3997 </tr>
3998 </tbody>
3999</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4000
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4001<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4002<pre>
4003 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4004 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4005 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4006 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4007</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4008
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4009</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4010
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4011<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4012<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4013 <a name="vectorops">Vector Operations</a>
4014</div>
4015
4016<div class="doc_text">
4017
4018<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4019 target-independent manner. These instructions cover the element-access and
4020 vector-specific operations needed to process vectors effectively. While LLVM
4021 does directly support these vector operations, many sophisticated algorithms
4022 will want to use target-specific intrinsics to take full advantage of a
4023 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4024
4025</div>
4026
4027<!-- _______________________________________________________________________ -->
4028<div class="doc_subsubsection">
4029 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4030</div>
4031
4032<div class="doc_text">
4033
4034<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4035<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4036 &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]4037</pre>
4038
4039<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4040<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4041 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4042
4043
4044<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4045<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4046 of <a href="#t_vector">vector</a> type. The second operand is an index
4047 indicating the position from which to extract the element. The index may be
4048 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4049
4050<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4051<p>The result is a scalar of the same type as the element type of
4052 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4053 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4054 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4055
4056<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4057<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4058 &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]4059</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4060
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4061</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4062
4063<!-- _______________________________________________________________________ -->
4064<div class="doc_subsubsection">
4065 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4066</div>
4067
4068<div class="doc_text">
4069
4070<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4071<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4072 &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]4073</pre>
4074
4075<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4076<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4077 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4078
4079<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4080<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4081 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4082 whose type must equal the element type of the first operand. The third
4083 operand is an index indicating the position at which to insert the value.
4084 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4085
4086<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4087<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4088 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4089 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4090 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4091
4092<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4093<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4094 &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]4095</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4096
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4097</div>
4098
4099<!-- _______________________________________________________________________ -->
4100<div class="doc_subsubsection">
4101 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4102</div>
4103
4104<div class="doc_text">
4105
4106<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4107<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4108 &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]4109</pre>
4110
4111<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4112<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4113 from two input vectors, returning a vector with the same element type as the
4114 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4115
4116<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4117<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4118 with types that match each other. The third argument is a shuffle mask whose
4119 element type is always 'i32'. The result of the instruction is a vector
4120 whose length is the same as the shuffle mask and whose element type is the
4121 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4122
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4123<p>The shuffle mask operand is required to be a constant vector with either
4124 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4125
4126<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4127<p>The elements of the two input vectors are numbered from left to right across
4128 both of the vectors. The shuffle mask operand specifies, for each element of
4129 the result vector, which element of the two input vectors the result element
4130 gets. The element selector may be undef (meaning "don't care") and the
4131 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4132
4133<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4134<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4135 &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]4136 &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]4137 &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]4138 &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]4139 &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]4140 &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]4141 &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]4142 &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]4143</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4144
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4145</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4146
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4147<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4148<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4149 <a name="aggregateops">Aggregate Operations</a>
4150</div>
4151
4152<div class="doc_text">
4153
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4154<p>LLVM supports several instructions for working with
4155 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4156
4157</div>
4158
4159<!-- _______________________________________________________________________ -->
4160<div class="doc_subsubsection">
4161 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4162</div>
4163
4164<div class="doc_text">
4165
4166<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4167<pre>
4168 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4169</pre>
4170
4171<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4172<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4173 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4174
4175<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4176<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4177 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4178 <a href="#t_array">array</a> type. The operands are constant indices to
4179 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4180 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4181
4182<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4183<p>The result is the value at the position in the aggregate specified by the
4184 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4185
4186<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4187<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4188 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4189</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4190
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4191</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4192
4193<!-- _______________________________________________________________________ -->
4194<div class="doc_subsubsection">
4195 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4196</div>
4197
4198<div class="doc_text">
4199
4200<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4201<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4202 &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]4203</pre>
4204
4205<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4206<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4207 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4208
4209<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4210<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4211 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4212 <a href="#t_array">array</a> type. The second operand is a first-class
4213 value to insert. The following operands are constant indices indicating
4214 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]4215 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4216 value to insert must have the same type as the value identified by the
4217 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4218
4219<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4220<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4221 that of <tt>val</tt> except that the value at the position specified by the
4222 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4223
4224<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4225<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4226 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4227 %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]4228</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4229
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4230</div>
4231
4232
4233<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4234<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4235 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4236</div>
4237
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4238<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4239
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4240<p>A key design point of an SSA-based representation is how it represents
4241 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4242 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4243 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4244
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4245</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4246
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4247<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4248<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4249 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4250</div>
4251
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4252<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4253
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4254<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4255<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4256 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4257</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4258
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4259<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4260<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4261 currently executing function, to be automatically released when this function
4262 returns to its caller. The object is always allocated in the generic address
4263 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4264
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4265<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4266<p>The '<tt>alloca</tt>' instruction
4267 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4268 runtime stack, returning a pointer of the appropriate type to the program.
4269 If "NumElements" is specified, it is the number of elements allocated,
4270 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4271 specified, the value result of the allocation is guaranteed to be aligned to
4272 at least that boundary. If not specified, or if zero, the target can choose
4273 to align the allocation on any convenient boundary compatible with the
4274 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4275
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4276<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4277
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4278<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4279<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4280 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4281 memory is automatically released when the function returns. The
4282 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4283 variables that must have an address available. When the function returns
4284 (either with the <tt><a href="#i_ret">ret</a></tt>
4285 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4286 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4287
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4288<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4289<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4290 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4291 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4292 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4293 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4294</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4295
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4296</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4297
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4298<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4299<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4300Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4301
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4302<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4303
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4304<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4305<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4306 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4307 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4308 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4309</pre>
4310
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4311<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4312<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4313
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4314<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4315<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4316 from which to load. The pointer must point to
4317 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4318 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4319 number or order of execution of this <tt>load</tt> with other <a
4320 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4321
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4322<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4323 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4324 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4325 alignment for the target. It is the responsibility of the code emitter to
4326 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4327 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4328 produce less efficient code. An alignment of 1 is always safe.</p>
4329
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4330<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4331 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4332 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4333 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4334 and code generator that this load is not expected to be reused in the cache.
4335 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4336 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4337
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4338<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4339<p>The location of memory pointed to is loaded. If the value being loaded is of
4340 scalar type then the number of bytes read does not exceed the minimum number
4341 of bytes needed to hold all bits of the type. For example, loading an
4342 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4343 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4344 is undefined if the value was not originally written using a store of the
4345 same type.</p>
4346
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4347<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4348<pre>
4349 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4350 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4351 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4352</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4353
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4354</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4355
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4356<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4357<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4358Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4359
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4360<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4361
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4362<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4363<pre>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4364 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4365 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]4366</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4367
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4368<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4369<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4370
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4371<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4372<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4373 and an address at which to store it. The type of the
4374 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4375 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4376 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4377 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4378 order of execution of this <tt>store</tt> with other <a
4379 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4380
4381<p>The optional constant "align" argument specifies the alignment of the
4382 operation (that is, the alignment of the memory address). A value of 0 or an
4383 omitted "align" argument means that the operation has the preferential
4384 alignment for the target. It is the responsibility of the code emitter to
4385 ensure that the alignment information is correct. Overestimating the
4386 alignment results in an undefined behavior. Underestimating the alignment may
4387 produce less efficient code. An alignment of 1 is always safe.</p>
4388
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4389<p>The optional !nontemporal metadata must reference a single metatadata
4390 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4391 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4392 instruction tells the optimizer and code generator that this load is
4393 not expected to be reused in the cache. The code generator may
4394 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4395 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4396
4397
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4398<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4399<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4400 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4401 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4402 does not exceed the minimum number of bytes needed to hold all bits of the
4403 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4404 writing a value of a type like <tt>i20</tt> with a size that is not an
4405 integral number of bytes, it is unspecified what happens to the extra bits
4406 that do not belong to the type, but they will typically be overwritten.</p>
4407
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4408<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4409<pre>
4410 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4411 store i32 3, i32* %ptr <i>; yields {void}</i>
4412 %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]4413</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4414
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4415</div>
4416
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4417<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4418<div class="doc_subsubsection">
4419 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4420</div>
4421
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4422<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4423
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4424<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4425<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4426 &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]4427 &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]4428</pre>
4429
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4430<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4431<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4432 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4433 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4434
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4435<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4436<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4437 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4438 elements of the aggregate object are indexed. The interpretation of each
4439 index is dependent on the type being indexed into. The first index always
4440 indexes the pointer value given as the first argument, the second index
4441 indexes a value of the type pointed to (not necessarily the value directly
4442 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4443 indexed into must be a pointer value, subsequent types can be arrays,
4444 vectors, structs and unions. Note that subsequent types being indexed into
4445 can never be pointers, since that would require loading the pointer before
4446 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4447
4448<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]4449 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4450 integer <b>constants</b> are allowed. When indexing into an array, pointer
4451 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]4452 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4453
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4454<p>For example, let's consider a C code fragment and how it gets compiled to
4455 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4456
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4457<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4458<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4459struct RT {
4460 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4461 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4462 char C;
4463};
4464struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4465 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4466 double Y;
4467 struct RT Z;
4468};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4469
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4470int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4471 return &amp;s[1].Z.B[5][13];
4472}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4473</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4474</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4475
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4476<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4477
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4478<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4479<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4480%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4481%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4482
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4483define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4484entry:
4485 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4486 ret i32* %reg
4487}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4488</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4489</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4490
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4491<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4492<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]4493 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4494 }</tt>' type, a structure. The second index indexes into the third element
4495 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4496 i8 }</tt>' type, another structure. The third index indexes into the second
4497 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4498 array. The two dimensions of the array are subscripted into, yielding an
4499 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4500 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4501
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4502<p>Note that it is perfectly legal to index partially through a structure,
4503 returning a pointer to an inner element. Because of this, the LLVM code for
4504 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4505
4506<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4507 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4508 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4509 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4510 %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]4511 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4512 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4513 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4514 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4515</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4516
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4517<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4518 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4519 base pointer is not an <i>in bounds</i> address of an allocated object,
4520 or if any of the addresses that would be formed by successive addition of
4521 the offsets implied by the indices to the base address with infinitely
4522 precise arithmetic are not an <i>in bounds</i> address of that allocated
4523 object. The <i>in bounds</i> addresses for an allocated object are all
4524 the addresses that point into the object, plus the address one byte past
4525 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4526
4527<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4528 the base address with silently-wrapping two's complement arithmetic, and
4529 the result value of the <tt>getelementptr</tt> may be outside the object
4530 pointed to by the base pointer. The result value may not necessarily be
4531 used to access memory though, even if it happens to point into allocated
4532 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4533 section for more information.</p>
4534
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4535<p>The getelementptr instruction is often confusing. For some more insight into
4536 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4537
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4538<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4539<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4540 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4541 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4542 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4543 %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]4544 <i>; yields i8*:eptr</i>
4545 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4546 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4547 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4548</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4549
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4550</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4551
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4552<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4553<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4554</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4555
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4556<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4557
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4558<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4559 which all take a single operand and a type. They perform various bit
4560 conversions on the operand.</p>
4561
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4562</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4563
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4564<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4565<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4566 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4567</div>
4568<div class="doc_text">
4569
4570<h5>Syntax:</h5>
4571<pre>
4572 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4573</pre>
4574
4575<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4576<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4577 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4578
4579<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4580<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4581 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4582 size and type of the result, which must be
4583 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4584 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4585 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4586
4587<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4588<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4589 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4590 source size must be larger than the destination size, <tt>trunc</tt> cannot
4591 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4592
4593<h5>Example:</h5>
4594<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4595 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4596 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4597 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4598</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4599
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4600</div>
4601
4602<!-- _______________________________________________________________________ -->
4603<div class="doc_subsubsection">
4604 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4605</div>
4606<div class="doc_text">
4607
4608<h5>Syntax:</h5>
4609<pre>
4610 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4611</pre>
4612
4613<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4614<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4615 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4616
4617
4618<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4619<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]4620 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4621 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]4622 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4623 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4624
4625<h5>Semantics:</h5>
4626<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]4627 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4628
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4629<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]4630
4631<h5>Example:</h5>
4632<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4633 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4634 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4635</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4636
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4637</div>
4638
4639<!-- _______________________________________________________________________ -->
4640<div class="doc_subsubsection">
4641 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4642</div>
4643<div class="doc_text">
4644
4645<h5>Syntax:</h5>
4646<pre>
4647 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4648</pre>
4649
4650<h5>Overview:</h5>
4651<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4652
4653<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4654<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]4655 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4656 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]4657 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4658 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4659
4660<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4661<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4662 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4663 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4664
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4665<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]4666
4667<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4668<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4669 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4670 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4671</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4672
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4673</div>
4674
4675<!-- _______________________________________________________________________ -->
4676<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4677 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4678</div>
4679
4680<div class="doc_text">
4681
4682<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4683<pre>
4684 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4685</pre>
4686
4687<h5>Overview:</h5>
4688<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4689 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4690
4691<h5>Arguments:</h5>
4692<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4693 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4694 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]4695 <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]4696 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4697
4698<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4699<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4700 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4701 <a href="#t_floating">floating point</a> type. If the value cannot fit
4702 within the destination type, <tt>ty2</tt>, then the results are
4703 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4704
4705<h5>Example:</h5>
4706<pre>
4707 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4708 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4709</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4710
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4711</div>
4712
4713<!-- _______________________________________________________________________ -->
4714<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4715 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4716</div>
4717<div class="doc_text">
4718
4719<h5>Syntax:</h5>
4720<pre>
4721 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4722</pre>
4723
4724<h5>Overview:</h5>
4725<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]4726 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4727
4728<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4729<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4730 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4731 a <a href="#t_floating">floating point</a> type to cast it to. The source
4732 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4733
4734<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4735<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4736 <a href="#t_floating">floating point</a> type to a larger
4737 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4738 used to make a <i>no-op cast</i> because it always changes bits. Use
4739 <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]4740
4741<h5>Example:</h5>
4742<pre>
4743 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4744 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4745</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4746
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4747</div>
4748
4749<!-- _______________________________________________________________________ -->
4750<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4751 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4752</div>
4753<div class="doc_text">
4754
4755<h5>Syntax:</h5>
4756<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4757 &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]4758</pre>
4759
4760<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4761<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4762 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4763
4764<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4765<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4766 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4767 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4768 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4769 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4770
4771<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4772<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4773 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4774 towards zero) unsigned integer value. If the value cannot fit
4775 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4776
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4777<h5>Example:</h5>
4778<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4779 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4780 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4781 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4782</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4783
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4784</div>
4785
4786<!-- _______________________________________________________________________ -->
4787<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4788 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4789</div>
4790<div class="doc_text">
4791
4792<h5>Syntax:</h5>
4793<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4794 &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]4795</pre>
4796
4797<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4798<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4799 <a href="#t_floating">floating point</a> <tt>value</tt> to
4800 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4801
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4802<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4803<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4804 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4805 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4806 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4807 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4808
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4809<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4810<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4811 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4812 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4813 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4814
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4815<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4816<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4817 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4818 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4819 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4820</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4821
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4822</div>
4823
4824<!-- _______________________________________________________________________ -->
4825<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4826 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4827</div>
4828<div class="doc_text">
4829
4830<h5>Syntax:</h5>
4831<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4832 &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]4833</pre>
4834
4835<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4836<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4837 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4838
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4839<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4840<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]4841 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4842 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4843 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4844 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4845
4846<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4847<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4848 integer quantity and converts it to the corresponding floating point
4849 value. If the value cannot fit in the floating point value, the results are
4850 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4851
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4852<h5>Example:</h5>
4853<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4854 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4855 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4856</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4857
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4858</div>
4859
4860<!-- _______________________________________________________________________ -->
4861<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4862 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4863</div>
4864<div class="doc_text">
4865
4866<h5>Syntax:</h5>
4867<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4868 &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]4869</pre>
4870
4871<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4872<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4873 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4874
4875<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4876<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]4877 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4878 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4879 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4880 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4881
4882<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4883<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4884 quantity and converts it to the corresponding floating point value. If the
4885 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4886
4887<h5>Example:</h5>
4888<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4889 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4890 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4891</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4892
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4893</div>
4894
4895<!-- _______________________________________________________________________ -->
4896<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4897 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4898</div>
4899<div class="doc_text">
4900
4901<h5>Syntax:</h5>
4902<pre>
4903 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4904</pre>
4905
4906<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4907<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4908 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4909
4910<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4911<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4912 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4913 <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]4914
4915<h5>Semantics:</h5>
4916<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4917 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4918 truncating or zero extending that value to the size of the integer type. If
4919 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4920 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4921 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4922 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4923
4924<h5>Example:</h5>
4925<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4926 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4927 %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]4928</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4929
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4930</div>
4931
4932<!-- _______________________________________________________________________ -->
4933<div class="doc_subsubsection">
4934 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4935</div>
4936<div class="doc_text">
4937
4938<h5>Syntax:</h5>
4939<pre>
4940 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4941</pre>
4942
4943<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4944<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4945 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4946
4947<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4948<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4949 value to cast, and a type to cast it to, which must be a
4950 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4951
4952<h5>Semantics:</h5>
4953<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4954 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4955 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4956 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4957 than the size of a pointer then a zero extension is done. If they are the
4958 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4959
4960<h5>Example:</h5>
4961<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4962 %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]4963 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4964 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4965</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4966
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4967</div>
4968
4969<!-- _______________________________________________________________________ -->
4970<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4971 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4972</div>
4973<div class="doc_text">
4974
4975<h5>Syntax:</h5>
4976<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4977 &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]4978</pre>
4979
4980<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4981<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4982 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4983
4984<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4985<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4986 non-aggregate first class value, and a type to cast it to, which must also be
4987 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4988 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4989 identical. If the source type is a pointer, the destination type must also be
4990 a pointer. This instruction supports bitwise conversion of vectors to
4991 integers and to vectors of other types (as long as they have the same
4992 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4993
4994<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4995<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4996 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4997 this conversion. The conversion is done as if the <tt>value</tt> had been
4998 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4999 be converted to other pointer types with this instruction. To convert
5000 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5001 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5002
5003<h5>Example:</h5>
5004<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5005 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5006 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5007 %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]5008</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5009
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5010</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5011
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5012<!-- ======================================================================= -->
5013<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5014
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5015<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5016
5017<p>The instructions in this category are the "miscellaneous" instructions, which
5018 defy better classification.</p>
5019
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5020</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5021
5022<!-- _______________________________________________________________________ -->
5023<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5024</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5025
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5026<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5027
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5028<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5029<pre>
5030 &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]5031</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5032
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5033<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5034<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5035 boolean values based on comparison of its two integer, integer vector, or
5036 pointer operands.</p>
5037
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5038<h5>Arguments:</h5>
5039<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5040 the condition code indicating the kind of comparison to perform. It is not a
5041 value, just a keyword. The possible condition code are:</p>
5042
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5043<ol>
5044 <li><tt>eq</tt>: equal</li>
5045 <li><tt>ne</tt>: not equal </li>
5046 <li><tt>ugt</tt>: unsigned greater than</li>
5047 <li><tt>uge</tt>: unsigned greater or equal</li>
5048 <li><tt>ult</tt>: unsigned less than</li>
5049 <li><tt>ule</tt>: unsigned less or equal</li>
5050 <li><tt>sgt</tt>: signed greater than</li>
5051 <li><tt>sge</tt>: signed greater or equal</li>
5052 <li><tt>slt</tt>: signed less than</li>
5053 <li><tt>sle</tt>: signed less or equal</li>
5054</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5055
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5056<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5057 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5058 typed. They must also be identical types.</p>
5059
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5060<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5061<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5062 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5063 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]5064 result, as follows:</p>
5065
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5066<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5067 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5068 <tt>false</tt> otherwise. No sign interpretation is necessary or
5069 performed.</li>
5070
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5071 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5072 <tt>false</tt> otherwise. No sign interpretation is necessary or
5073 performed.</li>
5074
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5075 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5076 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5077
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5078 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5079 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5080 to <tt>op2</tt>.</li>
5081
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5082 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5083 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5084
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5085 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5086 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5087
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5088 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5089 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5090
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5091 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5092 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5093 to <tt>op2</tt>.</li>
5094
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5095 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5096 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5097
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5098 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5099 <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]5100</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5101
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5102<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5103 values are compared as if they were integers.</p>
5104
5105<p>If the operands are integer vectors, then they are compared element by
5106 element. The result is an <tt>i1</tt> vector with the same number of elements
5107 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5108
5109<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5110<pre>
5111 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5112 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5113 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5114 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5115 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5116 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5117</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5118
5119<p>Note that the code generator does not yet support vector types with
5120 the <tt>icmp</tt> instruction.</p>
5121
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5122</div>
5123
5124<!-- _______________________________________________________________________ -->
5125<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5126</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5127
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5128<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5129
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5130<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5131<pre>
5132 &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]5133</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5134
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5135<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5136<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5137 values based on comparison of its operands.</p>
5138
5139<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]5140(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5141
5142<p>If the operands are floating point vectors, then the result type is a vector
5143 of boolean with the same number of elements as the operands being
5144 compared.</p>
5145
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5146<h5>Arguments:</h5>
5147<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5148 the condition code indicating the kind of comparison to perform. It is not a
5149 value, just a keyword. The possible condition code are:</p>
5150
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5151<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5152 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5153 <li><tt>oeq</tt>: ordered and equal</li>
5154 <li><tt>ogt</tt>: ordered and greater than </li>
5155 <li><tt>oge</tt>: ordered and greater than or equal</li>
5156 <li><tt>olt</tt>: ordered and less than </li>
5157 <li><tt>ole</tt>: ordered and less than or equal</li>
5158 <li><tt>one</tt>: ordered and not equal</li>
5159 <li><tt>ord</tt>: ordered (no nans)</li>
5160 <li><tt>ueq</tt>: unordered or equal</li>
5161 <li><tt>ugt</tt>: unordered or greater than </li>
5162 <li><tt>uge</tt>: unordered or greater than or equal</li>
5163 <li><tt>ult</tt>: unordered or less than </li>
5164 <li><tt>ule</tt>: unordered or less than or equal</li>
5165 <li><tt>une</tt>: unordered or not equal</li>
5166 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5167 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5168</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5169
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5170<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5171 <i>unordered</i> means that either operand may be a QNAN.</p>
5172
5173<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5174 a <a href="#t_floating">floating point</a> type or
5175 a <a href="#t_vector">vector</a> of floating point type. They must have
5176 identical types.</p>
5177
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5178<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5179<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5180 according to the condition code given as <tt>cond</tt>. If the operands are
5181 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5182 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5183 follows:</p>
5184
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5185<ol>
5186 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5187
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5188 <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]5189 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5190
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5191 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5192 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5193
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5194 <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]5195 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5196
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5197 <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]5198 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5199
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5200 <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]5201 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5202
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5203 <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]5204 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5205
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5206 <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]5207
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5208 <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]5209 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5210
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5211 <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]5212 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5213
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5214 <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]5215 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5216
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5217 <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]5218 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5219
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5220 <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]5221 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5222
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5223 <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]5224 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5225
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5226 <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]5227
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5228 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5229</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5230
5231<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5232<pre>
5233 &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]5234 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5235 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5236 &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]5237</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5238
5239<p>Note that the code generator does not yet support vector types with
5240 the <tt>fcmp</tt> instruction.</p>
5241
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5242</div>
5243
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5244<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5245<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5246 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5247</div>
5248
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5249<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5250
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5251<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5252<pre>
5253 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5254</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5255
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5256<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5257<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5258 SSA graph representing the function.</p>
5259
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5260<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5261<p>The type of the incoming values is specified with the first type field. After
5262 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5263 one pair for each predecessor basic block of the current block. Only values
5264 of <a href="#t_firstclass">first class</a> type may be used as the value
5265 arguments to the PHI node. Only labels may be used as the label
5266 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5267
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5268<p>There must be no non-phi instructions between the start of a basic block and
5269 the PHI instructions: i.e. PHI instructions must be first in a basic
5270 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5271
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5272<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5273 occur on the edge from the corresponding predecessor block to the current
5274 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5275 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5276
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5277<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5278<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5279 specified by the pair corresponding to the predecessor basic block that
5280 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5281
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5282<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5283<pre>
5284Loop: ; Infinite loop that counts from 0 on up...
5285 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5286 %nextindvar = add i32 %indvar, 1
5287 br label %Loop
5288</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5289
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5290</div>
5291
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5292<!-- _______________________________________________________________________ -->
5293<div class="doc_subsubsection">
5294 <a name="i_select">'<tt>select</tt>' Instruction</a>
5295</div>
5296
5297<div class="doc_text">
5298
5299<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5300<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5301 &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>
5302
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5303 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5304</pre>
5305
5306<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5307<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5308 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5309
5310
5311<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5312<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5313 values indicating the condition, and two values of the
5314 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5315 vectors and the condition is a scalar, then entire vectors are selected, not
5316 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5317
5318<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5319<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5320 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5321
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5322<p>If the condition is a vector of i1, then the value arguments must be vectors
5323 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5324
5325<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5326<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5327 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5328</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5329
5330<p>Note that the code generator does not yet support conditions
5331 with vector type.</p>
5332
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5333</div>
5334
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5335<!-- _______________________________________________________________________ -->
5336<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5337 <a name="i_call">'<tt>call</tt>' Instruction</a>
5338</div>
5339
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5340<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5341
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5342<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5343<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5344 &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]5345</pre>
5346
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5347<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5348<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5349
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5350<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5351<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5352
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5353<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5354 <li>The optional "tail" marker indicates that the callee function does not
5355 access any allocas or varargs in the caller. Note that calls may be
5356 marked "tail" even if they do not occur before
5357 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5358 present, the function call is eligible for tail call optimization,
5359 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5360 optimized into a jump</a>. The code generator may optimize calls marked
5361 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5362 sibling call optimization</a> when the caller and callee have
5363 matching signatures, or 2) forced tail call optimization when the
5364 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5365 <ul>
5366 <li>Caller and callee both have the calling
5367 convention <tt>fastcc</tt>.</li>
5368 <li>The call is in tail position (ret immediately follows call and ret
5369 uses value of call or is void).</li>
5370 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5371 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5372 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5373 constraints are met.</a></li>
5374 </ul>
5375 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5376
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5377 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5378 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5379 defaults to using C calling conventions. The calling convention of the
5380 call must match the calling convention of the target function, or else the
5381 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5382
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5383 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5384 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5385 '<tt>inreg</tt>' attributes are valid here.</li>
5386
5387 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5388 type of the return value. Functions that return no value are marked
5389 <tt><a href="#t_void">void</a></tt>.</li>
5390
5391 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5392 being invoked. The argument types must match the types implied by this
5393 signature. This type can be omitted if the function is not varargs and if
5394 the function type does not return a pointer to a function.</li>
5395
5396 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5397 be invoked. In most cases, this is a direct function invocation, but
5398 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5399 to function value.</li>
5400
5401 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5402 signature argument types and parameter attributes. All arguments must be
5403 of <a href="#t_firstclass">first class</a> type. If the function
5404 signature indicates the function accepts a variable number of arguments,
5405 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5406
5407 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5408 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5409 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5410</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5411
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5412<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5413<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5414 a specified function, with its incoming arguments bound to the specified
5415 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5416 function, control flow continues with the instruction after the function
5417 call, and the return value of the function is bound to the result
5418 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5419
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5420<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5421<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5422 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5423 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5424 %X = tail call i32 @foo() <i>; yields i32</i>
5425 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5426 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5427
5428 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5429 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5430 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5431 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5432 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5433 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5434</pre>
5435
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5436<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5437standard C99 library as being the C99 library functions, and may perform
5438optimizations or generate code for them under that assumption. This is
5439something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5440freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5441
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5442</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5443
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5444<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5445<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5446 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5447</div>
5448
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5449<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5450
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5451<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5452<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5453 &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]5454</pre>
5455
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5456<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5457<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5458 the "variable argument" area of a function call. It is used to implement the
5459 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5460
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5461<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5462<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5463 argument. It returns a value of the specified argument type and increments
5464 the <tt>va_list</tt> to point to the next argument. The actual type
5465 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5466
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5467<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5468<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5469 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5470 to the next argument. For more information, see the variable argument
5471 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5472
5473<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]5474 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5475 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5476
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5477<p><tt>va_arg</tt> is an LLVM instruction instead of
5478 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5479 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5480
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5481<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5482<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5483
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5484<p>Note that the code generator does not yet fully support va_arg on many
5485 targets. Also, it does not currently support va_arg with aggregate types on
5486 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5487
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5488</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5489
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5490<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5491<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5492<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5493
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5494<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5495
5496<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5497 well known names and semantics and are required to follow certain
5498 restrictions. Overall, these intrinsics represent an extension mechanism for
5499 the LLVM language that does not require changing all of the transformations
5500 in LLVM when adding to the language (or the bitcode reader/writer, the
5501 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5502
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5503<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5504 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5505 begin with this prefix. Intrinsic functions must always be external
5506 functions: you cannot define the body of intrinsic functions. Intrinsic
5507 functions may only be used in call or invoke instructions: it is illegal to
5508 take the address of an intrinsic function. Additionally, because intrinsic
5509 functions are part of the LLVM language, it is required if any are added that
5510 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5511
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5512<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5513 family of functions that perform the same operation but on different data
5514 types. Because LLVM can represent over 8 million different integer types,
5515 overloading is used commonly to allow an intrinsic function to operate on any
5516 integer type. One or more of the argument types or the result type can be
5517 overloaded to accept any integer type. Argument types may also be defined as
5518 exactly matching a previous argument's type or the result type. This allows
5519 an intrinsic function which accepts multiple arguments, but needs all of them
5520 to be of the same type, to only be overloaded with respect to a single
5521 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5522
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5523<p>Overloaded intrinsics will have the names of its overloaded argument types
5524 encoded into its function name, each preceded by a period. Only those types
5525 which are overloaded result in a name suffix. Arguments whose type is matched
5526 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5527 can take an integer of any width and returns an integer of exactly the same
5528 integer width. This leads to a family of functions such as
5529 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5530 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5531 suffix is required. Because the argument's type is matched against the return
5532 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5533
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5534<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5535 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5536
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5537</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5538
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5539<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5540<div class="doc_subsection">
5541 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5542</div>
5543
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5544<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5545
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5546<p>Variable argument support is defined in LLVM with
5547 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5548 intrinsic functions. These functions are related to the similarly named
5549 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5550
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5551<p>All of these functions operate on arguments that use a target-specific value
5552 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5553 not define what this type is, so all transformations should be prepared to
5554 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5555
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5556<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]5557 instruction and the variable argument handling intrinsic functions are
5558 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5559
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5560<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5561<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5562define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5563 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5564 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5565 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5566 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5567
5568 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5569 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5570
5571 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5572 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5573 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5574 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5575 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5576
5577 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5578 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5579 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5580}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5581
5582declare void @llvm.va_start(i8*)
5583declare void @llvm.va_copy(i8*, i8*)
5584declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5585</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5586</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5587
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5588</div>
5589
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5590<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5591<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5592 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5593</div>
5594
5595
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5596<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5597
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5598<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5599<pre>
5600 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5601</pre>
5602
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5603<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5604<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5605 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]5606
5607<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5608<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]5609
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5610<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5611<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]5612 macro available in C. In a target-dependent way, it initializes
5613 the <tt>va_list</tt> element to which the argument points, so that the next
5614 call to <tt>va_arg</tt> will produce the first variable argument passed to
5615 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5616 need to know the last argument of the function as the compiler can figure
5617 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5618
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5619</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5620
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5621<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5622<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5623 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5624</div>
5625
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5626<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5627
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5628<h5>Syntax:</h5>
5629<pre>
5630 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5631</pre>
5632
5633<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5634<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5635 which has been initialized previously
5636 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5637 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5638
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5639<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5640<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]5641
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5642<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5643<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]5644 macro available in C. In a target-dependent way, it destroys
5645 the <tt>va_list</tt> element to which the argument points. Calls
5646 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5647 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5648 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5649
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5650</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5651
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5652<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5653<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5654 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5655</div>
5656
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5657<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5658
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5659<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5660<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5661 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5662</pre>
5663
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5664<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5665<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5666 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5667
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5668<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5669<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]5670 The second argument is a pointer to a <tt>va_list</tt> element to copy
5671 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5672
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5673<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5674<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]5675 macro available in C. In a target-dependent way, it copies the
5676 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5677 element. This intrinsic is necessary because
5678 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5679 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5680
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5681</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5682
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5683<!-- ======================================================================= -->
5684<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5685 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5686</div>
5687
5688<div class="doc_text">
5689
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5690<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5691Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5692intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5693roots on the stack</a>, as well as garbage collector implementations that
5694require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5695barriers. Front-ends for type-safe garbage collected languages should generate
5696these intrinsics to make use of the LLVM garbage collectors. For more details,
5697see <a href="GarbageCollection.html">Accurate Garbage Collection with
5698LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5699
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5700<p>The garbage collection intrinsics only operate on objects in the generic
5701 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5702
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5703</div>
5704
5705<!-- _______________________________________________________________________ -->
5706<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5707 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5708</div>
5709
5710<div class="doc_text">
5711
5712<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5713<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5714 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5715</pre>
5716
5717<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5718<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]5719 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5720
5721<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5722<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5723 root pointer. The second pointer (which must be either a constant or a
5724 global value address) contains the meta-data to be associated with the
5725 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5726
5727<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5728<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]5729 location. At compile-time, the code generator generates information to allow
5730 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5731 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5732 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5733
5734</div>
5735
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5736<!-- _______________________________________________________________________ -->
5737<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5738 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5739</div>
5740
5741<div class="doc_text">
5742
5743<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5744<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5745 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5746</pre>
5747
5748<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5749<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5750 locations, allowing garbage collector implementations that require read
5751 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5752
5753<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5754<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]5755 allocated from the garbage collector. The first object is a pointer to the
5756 start of the referenced object, if needed by the language runtime (otherwise
5757 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5758
5759<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5760<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5761 instruction, but may be replaced with substantially more complex code by the
5762 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5763 may only be used in a function which <a href="#gc">specifies a GC
5764 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5765
5766</div>
5767
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5768<!-- _______________________________________________________________________ -->
5769<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5770 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5771</div>
5772
5773<div class="doc_text">
5774
5775<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5776<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5777 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5778</pre>
5779
5780<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5781<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5782 locations, allowing garbage collector implementations that require write
5783 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5784
5785<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5786<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]5787 object to store it to, and the third is the address of the field of Obj to
5788 store to. If the runtime does not require a pointer to the object, Obj may
5789 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5790
5791<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5792<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5793 instruction, but may be replaced with substantially more complex code by the
5794 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5795 may only be used in a function which <a href="#gc">specifies a GC
5796 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5797
5798</div>
5799
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5800<!-- ======================================================================= -->
5801<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5802 <a name="int_codegen">Code Generator Intrinsics</a>
5803</div>
5804
5805<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5806
5807<p>These intrinsics are provided by LLVM to expose special features that may
5808 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5809
5810</div>
5811
5812<!-- _______________________________________________________________________ -->
5813<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5814 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5815</div>
5816
5817<div class="doc_text">
5818
5819<h5>Syntax:</h5>
5820<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5821 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5822</pre>
5823
5824<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5825<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5826 target-specific value indicating the return address of the current function
5827 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5828
5829<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5830<p>The argument to this intrinsic indicates which function to return the address
5831 for. Zero indicates the calling function, one indicates its caller, etc.
5832 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5833
5834<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5835<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5836 indicating the return address of the specified call frame, or zero if it
5837 cannot be identified. The value returned by this intrinsic is likely to be
5838 incorrect or 0 for arguments other than zero, so it should only be used for
5839 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5840
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5841<p>Note that calling this intrinsic does not prevent function inlining or other
5842 aggressive transformations, so the value returned may not be that of the
5843 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5844
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5845</div>
5846
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5847<!-- _______________________________________________________________________ -->
5848<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5849 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5850</div>
5851
5852<div class="doc_text">
5853
5854<h5>Syntax:</h5>
5855<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5856 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5857</pre>
5858
5859<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5860<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5861 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5862
5863<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5864<p>The argument to this intrinsic indicates which function to return the frame
5865 pointer for. Zero indicates the calling function, one indicates its caller,
5866 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5867
5868<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5869<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5870 indicating the frame address of the specified call frame, or zero if it
5871 cannot be identified. The value returned by this intrinsic is likely to be
5872 incorrect or 0 for arguments other than zero, so it should only be used for
5873 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5874
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5875<p>Note that calling this intrinsic does not prevent function inlining or other
5876 aggressive transformations, so the value returned may not be that of the
5877 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5878
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5879</div>
5880
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5881<!-- _______________________________________________________________________ -->
5882<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5883 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5884</div>
5885
5886<div class="doc_text">
5887
5888<h5>Syntax:</h5>
5889<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5890 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5891</pre>
5892
5893<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5894<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5895 of the function stack, for use
5896 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5897 useful for implementing language features like scoped automatic variable
5898 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5899
5900<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5901<p>This intrinsic returns a opaque pointer value that can be passed
5902 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5903 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5904 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5905 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5906 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5907 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5908
5909</div>
5910
5911<!-- _______________________________________________________________________ -->
5912<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5913 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5914</div>
5915
5916<div class="doc_text">
5917
5918<h5>Syntax:</h5>
5919<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5920 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5921</pre>
5922
5923<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5924<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5925 the function stack to the state it was in when the
5926 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5927 executed. This is useful for implementing language features like scoped
5928 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5929
5930<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5931<p>See the description
5932 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5933
5934</div>
5935
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5936<!-- _______________________________________________________________________ -->
5937<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5938 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5939</div>
5940
5941<div class="doc_text">
5942
5943<h5>Syntax:</h5>
5944<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5945 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]5946</pre>
5947
5948<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5949<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5950 insert a prefetch instruction if supported; otherwise, it is a noop.
5951 Prefetches have no effect on the behavior of the program but can change its
5952 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5953
5954<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5955<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5956 specifier determining if the fetch should be for a read (0) or write (1),
5957 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5958 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5959 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5960
5961<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5962<p>This intrinsic does not modify the behavior of the program. In particular,
5963 prefetches cannot trap and do not produce a value. On targets that support
5964 this intrinsic, the prefetch can provide hints to the processor cache for
5965 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5966
5967</div>
5968
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5969<!-- _______________________________________________________________________ -->
5970<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5971 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5972</div>
5973
5974<div class="doc_text">
5975
5976<h5>Syntax:</h5>
5977<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5978 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5979</pre>
5980
5981<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5982<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5983 Counter (PC) in a region of code to simulators and other tools. The method
5984 is target specific, but it is expected that the marker will use exported
5985 symbols to transmit the PC of the marker. The marker makes no guarantees
5986 that it will remain with any specific instruction after optimizations. It is
5987 possible that the presence of a marker will inhibit optimizations. The
5988 intended use is to be inserted after optimizations to allow correlations of
5989 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5990
5991<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5992<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5993
5994<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5995<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5996 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5997
5998</div>
5999
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6000<!-- _______________________________________________________________________ -->
6001<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6002 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6003</div>
6004
6005<div class="doc_text">
6006
6007<h5>Syntax:</h5>
6008<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6009 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6010</pre>
6011
6012<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6013<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6014 counter register (or similar low latency, high accuracy clocks) on those
6015 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6016 should map to RPCC. As the backing counters overflow quickly (on the order
6017 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6018
6019<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6020<p>When directly supported, reading the cycle counter should not modify any
6021 memory. Implementations are allowed to either return a application specific
6022 value or a system wide value. On backends without support, this is lowered
6023 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6024
6025</div>
6026
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6027<!-- ======================================================================= -->
6028<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6029 <a name="int_libc">Standard C Library Intrinsics</a>
6030</div>
6031
6032<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6033
6034<p>LLVM provides intrinsics for a few important standard C library functions.
6035 These intrinsics allow source-language front-ends to pass information about
6036 the alignment of the pointer arguments to the code generator, providing
6037 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6038
6039</div>
6040
6041<!-- _______________________________________________________________________ -->
6042<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6043 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6044</div>
6045
6046<div class="doc_text">
6047
6048<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6049<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6050 integer bit width and for different address spaces. Not all targets support
6051 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6052
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6053<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6054 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6055 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6056 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6057 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6058</pre>
6059
6060<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6061<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6062 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6063
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6064<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6065 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6066 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6067
6068<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6069
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6070<p>The first argument is a pointer to the destination, the second is a pointer
6071 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6072 number of bytes to copy, the fourth argument is the alignment of the
6073 source and destination locations, and the fifth is a boolean indicating a
6074 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6075
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6076<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6077 then the caller guarantees that both the source and destination pointers are
6078 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6079
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6080<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6081 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6082 The detailed access behavior is not very cleanly specified and it is unwise
6083 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6084
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6085<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6086
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6087<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6088 source location to the destination location, which are not allowed to
6089 overlap. It copies "len" bytes of memory over. If the argument is known to
6090 be aligned to some boundary, this can be specified as the fourth argument,
6091 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6092
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6093</div>
6094
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6095<!-- _______________________________________________________________________ -->
6096<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6097 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6098</div>
6099
6100<div class="doc_text">
6101
6102<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6103<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6104 width and for different address space. Not all targets support all bit
6105 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6106
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6107<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6108 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6109 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6110 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6111 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6112</pre>
6113
6114<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6115<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6116 source location to the destination location. It is similar to the
6117 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6118 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6119
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6120<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6121 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6122 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6123
6124<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6125
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6126<p>The first argument is a pointer to the destination, the second is a pointer
6127 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6128 number of bytes to copy, the fourth argument is the alignment of the
6129 source and destination locations, and the fifth is a boolean indicating a
6130 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6131
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6132<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6133 then the caller guarantees that the source and destination pointers are
6134 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6135
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6136<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6137 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6138 The detailed access behavior is not very cleanly specified and it is unwise
6139 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6140
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6141<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6142
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6143<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6144 source location to the destination location, which may overlap. It copies
6145 "len" bytes of memory over. If the argument is known to be aligned to some
6146 boundary, this can be specified as the fourth argument, otherwise it should
6147 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6148
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6149</div>
6150
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6151<!-- _______________________________________________________________________ -->
6152<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6153 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6154</div>
6155
6156<div class="doc_text">
6157
6158<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6159<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6160 width and for different address spaces. Not all targets support all bit
6161 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6162
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6163<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6164 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6165 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6166 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6167 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6168</pre>
6169
6170<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6171<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6172 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6173
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6174<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6175 intrinsic does not return a value, takes extra alignment/volatile arguments,
6176 and the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6177
6178<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6179<p>The first argument is a pointer to the destination to fill, the second is the
6180 byte value to fill it with, the third argument is an integer argument
6181 specifying the number of bytes to fill, and the fourth argument is the known
6182 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6183
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6184<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6185 then the caller guarantees that the destination pointer is aligned to that
6186 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6187
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6188<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6189 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6190 The detailed access behavior is not very cleanly specified and it is unwise
6191 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6192
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6193<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6194<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6195 at the destination location. If the argument is known to be aligned to some
6196 boundary, this can be specified as the fourth argument, otherwise it should
6197 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6198
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6199</div>
6200
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6201<!-- _______________________________________________________________________ -->
6202<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6203 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6204</div>
6205
6206<div class="doc_text">
6207
6208<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6209<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6210 floating point or vector of floating point type. Not all targets support all
6211 types however.</p>
6212
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6213<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6214 declare float @llvm.sqrt.f32(float %Val)
6215 declare double @llvm.sqrt.f64(double %Val)
6216 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6217 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6218 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6219</pre>
6220
6221<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6222<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6223 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6224 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6225 behavior for negative numbers other than -0.0 (which allows for better
6226 optimization, because there is no need to worry about errno being
6227 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]6228
6229<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6230<p>The argument and return value are floating point numbers of the same
6231 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6232
6233<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6234<p>This function returns the sqrt of the specified operand if it is a
6235 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6236
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6237</div>
6238
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6239<!-- _______________________________________________________________________ -->
6240<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6241 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6242</div>
6243
6244<div class="doc_text">
6245
6246<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6247<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6248 floating point or vector of floating point type. Not all targets support all
6249 types however.</p>
6250
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6251<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6252 declare float @llvm.powi.f32(float %Val, i32 %power)
6253 declare double @llvm.powi.f64(double %Val, i32 %power)
6254 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6255 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6256 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6257</pre>
6258
6259<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6260<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6261 specified (positive or negative) power. The order of evaluation of
6262 multiplications is not defined. When a vector of floating point type is
6263 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6264
6265<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6266<p>The second argument is an integer power, and the first is a value to raise to
6267 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6268
6269<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6270<p>This function returns the first value raised to the second power with an
6271 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6272
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6273</div>
6274
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6275<!-- _______________________________________________________________________ -->
6276<div class="doc_subsubsection">
6277 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6278</div>
6279
6280<div class="doc_text">
6281
6282<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6283<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6284 floating point or vector of floating point type. Not all targets support all
6285 types however.</p>
6286
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6287<pre>
6288 declare float @llvm.sin.f32(float %Val)
6289 declare double @llvm.sin.f64(double %Val)
6290 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6291 declare fp128 @llvm.sin.f128(fp128 %Val)
6292 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6293</pre>
6294
6295<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6296<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6297
6298<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6299<p>The argument and return value are floating point numbers of the same
6300 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6301
6302<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6303<p>This function returns the sine of the specified operand, returning the same
6304 values as the libm <tt>sin</tt> functions would, and handles error conditions
6305 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6306
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6307</div>
6308
6309<!-- _______________________________________________________________________ -->
6310<div class="doc_subsubsection">
6311 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6312</div>
6313
6314<div class="doc_text">
6315
6316<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6317<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6318 floating point or vector of floating point type. Not all targets support all
6319 types however.</p>
6320
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6321<pre>
6322 declare float @llvm.cos.f32(float %Val)
6323 declare double @llvm.cos.f64(double %Val)
6324 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6325 declare fp128 @llvm.cos.f128(fp128 %Val)
6326 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6327</pre>
6328
6329<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6330<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6331
6332<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6333<p>The argument and return value are floating point numbers of the same
6334 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6335
6336<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6337<p>This function returns the cosine of the specified operand, returning the same
6338 values as the libm <tt>cos</tt> functions would, and handles error conditions
6339 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6340
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6341</div>
6342
6343<!-- _______________________________________________________________________ -->
6344<div class="doc_subsubsection">
6345 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6346</div>
6347
6348<div class="doc_text">
6349
6350<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6351<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6352 floating point or vector of floating point type. Not all targets support all
6353 types however.</p>
6354
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6355<pre>
6356 declare float @llvm.pow.f32(float %Val, float %Power)
6357 declare double @llvm.pow.f64(double %Val, double %Power)
6358 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6359 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6360 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6361</pre>
6362
6363<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6364<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6365 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6366
6367<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6368<p>The second argument is a floating point power, and the first is a value to
6369 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6370
6371<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6372<p>This function returns the first value raised to the second power, returning
6373 the same values as the libm <tt>pow</tt> functions would, and handles error
6374 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6375
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6376</div>
6377
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6378<!-- ======================================================================= -->
6379<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6380 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6381</div>
6382
6383<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6384
6385<p>LLVM provides intrinsics for a few important bit manipulation operations.
6386 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6387
6388</div>
6389
6390<!-- _______________________________________________________________________ -->
6391<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6392 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6393</div>
6394
6395<div class="doc_text">
6396
6397<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6398<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6399 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6400
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6401<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6402 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6403 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6404 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6405</pre>
6406
6407<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6408<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6409 values with an even number of bytes (positive multiple of 16 bits). These
6410 are useful for performing operations on data that is not in the target's
6411 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6412
6413<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6414<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6415 and low byte of the input i16 swapped. Similarly,
6416 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6417 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6418 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6419 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6420 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6421 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6422
6423</div>
6424
6425<!-- _______________________________________________________________________ -->
6426<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6427 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6428</div>
6429
6430<div class="doc_text">
6431
6432<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6433<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]6434 width. Not all targets support all bit widths however.</p>
6435
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6436<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6437 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6438 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6439 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6440 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6441 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6442</pre>
6443
6444<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6445<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6446 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6447
6448<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6449<p>The only argument is the value to be counted. The argument may be of any
6450 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6451
6452<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6453<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]6454
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6455</div>
6456
6457<!-- _______________________________________________________________________ -->
6458<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6459 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6460</div>
6461
6462<div class="doc_text">
6463
6464<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6465<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6466 integer bit width. Not all targets support all bit widths however.</p>
6467
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6468<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6469 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6470 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6471 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6472 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6473 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6474</pre>
6475
6476<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6477<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6478 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6479
6480<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6481<p>The only argument is the value to be counted. The argument may be of any
6482 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6483
6484<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6485<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6486 zeros in a variable. If the src == 0 then the result is the size in bits of
6487 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6488
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6489</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6490
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6491<!-- _______________________________________________________________________ -->
6492<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6493 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6494</div>
6495
6496<div class="doc_text">
6497
6498<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6499<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6500 integer bit width. Not all targets support all bit widths however.</p>
6501
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6502<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6503 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6504 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6505 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6506 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6507 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6508</pre>
6509
6510<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6511<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6512 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6513
6514<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6515<p>The only argument is the value to be counted. The argument may be of any
6516 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6517
6518<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6519<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6520 zeros in a variable. If the src == 0 then the result is the size in bits of
6521 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6522
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6523</div>
6524
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6525<!-- ======================================================================= -->
6526<div class="doc_subsection">
6527 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6528</div>
6529
6530<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6531
6532<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6533
6534</div>
6535
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6536<!-- _______________________________________________________________________ -->
6537<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6538 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6539</div>
6540
6541<div class="doc_text">
6542
6543<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6544<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]6545 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6546
6547<pre>
6548 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6549 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6550 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6551</pre>
6552
6553<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6554<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6555 a signed addition of the two arguments, and indicate whether an overflow
6556 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6557
6558<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6559<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]6560 be of integer types of any bit width, but they must have the same bit
6561 width. The second element of the result structure must be of
6562 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6563 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6564
6565<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6566<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6567 a signed addition of the two variables. They return a structure &mdash; the
6568 first element of which is the signed summation, and the second element of
6569 which is a bit specifying if the signed summation resulted in an
6570 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6571
6572<h5>Examples:</h5>
6573<pre>
6574 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6575 %sum = extractvalue {i32, i1} %res, 0
6576 %obit = extractvalue {i32, i1} %res, 1
6577 br i1 %obit, label %overflow, label %normal
6578</pre>
6579
6580</div>
6581
6582<!-- _______________________________________________________________________ -->
6583<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6584 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6585</div>
6586
6587<div class="doc_text">
6588
6589<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6590<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]6591 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6592
6593<pre>
6594 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6595 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6596 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6597</pre>
6598
6599<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6600<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6601 an unsigned addition of the two arguments, and indicate whether a carry
6602 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6603
6604<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6605<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]6606 be of integer types of any bit width, but they must have the same bit
6607 width. The second element of the result structure must be of
6608 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6609 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6610
6611<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6612<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6613 an unsigned addition of the two arguments. They return a structure &mdash;
6614 the first element of which is the sum, and the second element of which is a
6615 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6616
6617<h5>Examples:</h5>
6618<pre>
6619 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6620 %sum = extractvalue {i32, i1} %res, 0
6621 %obit = extractvalue {i32, i1} %res, 1
6622 br i1 %obit, label %carry, label %normal
6623</pre>
6624
6625</div>
6626
6627<!-- _______________________________________________________________________ -->
6628<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6629 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6630</div>
6631
6632<div class="doc_text">
6633
6634<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6635<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]6636 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6637
6638<pre>
6639 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6640 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6641 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6642</pre>
6643
6644<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6645<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6646 a signed subtraction of the two arguments, and indicate whether an overflow
6647 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6648
6649<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6650<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]6651 be of integer types of any bit width, but they must have the same bit
6652 width. The second element of the result structure must be of
6653 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6654 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6655
6656<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6657<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6658 a signed subtraction of the two arguments. They return a structure &mdash;
6659 the first element of which is the subtraction, and the second element of
6660 which is a bit specifying if the signed subtraction resulted in an
6661 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6662
6663<h5>Examples:</h5>
6664<pre>
6665 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6666 %sum = extractvalue {i32, i1} %res, 0
6667 %obit = extractvalue {i32, i1} %res, 1
6668 br i1 %obit, label %overflow, label %normal
6669</pre>
6670
6671</div>
6672
6673<!-- _______________________________________________________________________ -->
6674<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6675 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6676</div>
6677
6678<div class="doc_text">
6679
6680<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6681<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]6682 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6683
6684<pre>
6685 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6686 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6687 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6688</pre>
6689
6690<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6691<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6692 an unsigned subtraction of the two arguments, and indicate whether an
6693 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6694
6695<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6696<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]6697 be of integer types of any bit width, but they must have the same bit
6698 width. The second element of the result structure must be of
6699 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6700 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6701
6702<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6703<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6704 an unsigned subtraction of the two arguments. They return a structure &mdash;
6705 the first element of which is the subtraction, and the second element of
6706 which is a bit specifying if the unsigned subtraction resulted in an
6707 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6708
6709<h5>Examples:</h5>
6710<pre>
6711 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6712 %sum = extractvalue {i32, i1} %res, 0
6713 %obit = extractvalue {i32, i1} %res, 1
6714 br i1 %obit, label %overflow, label %normal
6715</pre>
6716
6717</div>
6718
6719<!-- _______________________________________________________________________ -->
6720<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6721 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6722</div>
6723
6724<div class="doc_text">
6725
6726<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6727<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]6728 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6729
6730<pre>
6731 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6732 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6733 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6734</pre>
6735
6736<h5>Overview:</h5>
6737
6738<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6739 a signed multiplication of the two arguments, and indicate whether an
6740 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6741
6742<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6743<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]6744 be of integer types of any bit width, but they must have the same bit
6745 width. The second element of the result structure must be of
6746 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6747 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6748
6749<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6750<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6751 a signed multiplication of the two arguments. They return a structure &mdash;
6752 the first element of which is the multiplication, and the second element of
6753 which is a bit specifying if the signed multiplication resulted in an
6754 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6755
6756<h5>Examples:</h5>
6757<pre>
6758 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6759 %sum = extractvalue {i32, i1} %res, 0
6760 %obit = extractvalue {i32, i1} %res, 1
6761 br i1 %obit, label %overflow, label %normal
6762</pre>
6763
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6764</div>
6765
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6766<!-- _______________________________________________________________________ -->
6767<div class="doc_subsubsection">
6768 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6769</div>
6770
6771<div class="doc_text">
6772
6773<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6774<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]6775 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6776
6777<pre>
6778 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6779 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6780 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6781</pre>
6782
6783<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6784<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6785 a unsigned multiplication of the two arguments, and indicate whether an
6786 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6787
6788<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6789<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]6790 be of integer types of any bit width, but they must have the same bit
6791 width. The second element of the result structure must be of
6792 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6793 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6794
6795<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6796<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6797 an unsigned multiplication of the two arguments. They return a structure
6798 &mdash; the first element of which is the multiplication, and the second
6799 element of which is a bit specifying if the unsigned multiplication resulted
6800 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6801
6802<h5>Examples:</h5>
6803<pre>
6804 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6805 %sum = extractvalue {i32, i1} %res, 0
6806 %obit = extractvalue {i32, i1} %res, 1
6807 br i1 %obit, label %overflow, label %normal
6808</pre>
6809
6810</div>
6811
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6812<!-- ======================================================================= -->
6813<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6814 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6815</div>
6816
6817<div class="doc_text">
6818
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6819<p>Half precision floating point is a storage-only format. This means that it is
6820 a dense encoding (in memory) but does not support computation in the
6821 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6822
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6823<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6824 value as an i16, then convert it to float with <a
6825 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6826 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6827 double etc). To store the value back to memory, it is first converted to
6828 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6829 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6830 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6831</div>
6832
6833<!-- _______________________________________________________________________ -->
6834<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6835 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6836</div>
6837
6838<div class="doc_text">
6839
6840<h5>Syntax:</h5>
6841<pre>
6842 declare i16 @llvm.convert.to.fp16(f32 %a)
6843</pre>
6844
6845<h5>Overview:</h5>
6846<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6847 a conversion from single precision floating point format to half precision
6848 floating point format.</p>
6849
6850<h5>Arguments:</h5>
6851<p>The intrinsic function contains single argument - the value to be
6852 converted.</p>
6853
6854<h5>Semantics:</h5>
6855<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6856 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6857 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6858 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6859
6860<h5>Examples:</h5>
6861<pre>
6862 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6863 store i16 %res, i16* @x, align 2
6864</pre>
6865
6866</div>
6867
6868<!-- _______________________________________________________________________ -->
6869<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6870 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6871</div>
6872
6873<div class="doc_text">
6874
6875<h5>Syntax:</h5>
6876<pre>
6877 declare f32 @llvm.convert.from.fp16(i16 %a)
6878</pre>
6879
6880<h5>Overview:</h5>
6881<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6882 a conversion from half precision floating point format to single precision
6883 floating point format.</p>
6884
6885<h5>Arguments:</h5>
6886<p>The intrinsic function contains single argument - the value to be
6887 converted.</p>
6888
6889<h5>Semantics:</h5>
6890<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6891 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6892 precision floating point format. The input half-float value is represented by
6893 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6894
6895<h5>Examples:</h5>
6896<pre>
6897 %a = load i16* @x, align 2
6898 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6899</pre>
6900
6901</div>
6902
6903<!-- ======================================================================= -->
6904<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6905 <a name="int_debugger">Debugger Intrinsics</a>
6906</div>
6907
6908<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6909
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6910<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6911 prefix), are described in
6912 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6913 Level Debugging</a> document.</p>
6914
6915</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6916
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6917<!-- ======================================================================= -->
6918<div class="doc_subsection">
6919 <a name="int_eh">Exception Handling Intrinsics</a>
6920</div>
6921
6922<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6923
6924<p>The LLVM exception handling intrinsics (which all start with
6925 <tt>llvm.eh.</tt> prefix), are described in
6926 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6927 Handling</a> document.</p>
6928
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6929</div>
6930
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6931<!-- ======================================================================= -->
6932<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6933 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6934</div>
6935
6936<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6937
6938<p>This intrinsic makes it possible to excise one parameter, marked with
6939 the <tt>nest</tt> attribute, from a function. The result is a callable
6940 function pointer lacking the nest parameter - the caller does not need to
6941 provide a value for it. Instead, the value to use is stored in advance in a
6942 "trampoline", a block of memory usually allocated on the stack, which also
6943 contains code to splice the nest value into the argument list. This is used
6944 to implement the GCC nested function address extension.</p>
6945
6946<p>For example, if the function is
6947 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6948 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6949 follows:</p>
6950
6951<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6952<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6953 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6954 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6955 %p = call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6956 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6957</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6958</div>
6959
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6960<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6961 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6962
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6963</div>
6964
6965<!-- _______________________________________________________________________ -->
6966<div class="doc_subsubsection">
6967 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6968</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6969
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6970<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6971
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6972<h5>Syntax:</h5>
6973<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6974 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]6975</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6976
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6977<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6978<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6979 function pointer suitable for executing it.</p>
6980
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6981<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6982<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6983 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6984 sufficiently aligned block of memory; this memory is written to by the
6985 intrinsic. Note that the size and the alignment are target-specific - LLVM
6986 currently provides no portable way of determining them, so a front-end that
6987 generates this intrinsic needs to have some target-specific knowledge.
6988 The <tt>func</tt> argument must hold a function bitcast to
6989 an <tt>i8*</tt>.</p>
6990
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6991<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6992<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6993 dependent code, turning it into a function. A pointer to this function is
6994 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6995 function pointer type</a> before being called. The new function's signature
6996 is the same as that of <tt>func</tt> with any arguments marked with
6997 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6998 is allowed, and it must be of pointer type. Calling the new function is
6999 equivalent to calling <tt>func</tt> with the same argument list, but
7000 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
7001 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
7002 by <tt>tramp</tt> is modified, then the effect of any later call to the
7003 returned function pointer is undefined.</p>
7004
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7005</div>
7006
7007<!-- ======================================================================= -->
7008<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7009 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
7010</div>
7011
7012<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7013
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7014<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7015 hardware constructs for atomic operations and memory synchronization. This
7016 provides an interface to the hardware, not an interface to the programmer. It
7017 is aimed at a low enough level to allow any programming models or APIs
7018 (Application Programming Interfaces) which need atomic behaviors to map
7019 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7020 hardware provides a "universal IR" for source languages, it also provides a
7021 starting point for developing a "universal" atomic operation and
7022 synchronization IR.</p>
7023
7024<p>These do <em>not</em> form an API such as high-level threading libraries,
7025 software transaction memory systems, atomic primitives, and intrinsic
7026 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7027 application libraries. The hardware interface provided by LLVM should allow
7028 a clean implementation of all of these APIs and parallel programming models.
7029 No one model or paradigm should be selected above others unless the hardware
7030 itself ubiquitously does so.</p>
7031
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7032</div>
7033
7034<!-- _______________________________________________________________________ -->
7035<div class="doc_subsubsection">
7036 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7037</div>
7038<div class="doc_text">
7039<h5>Syntax:</h5>
7040<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7041 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]7042</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7043
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7044<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7045<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7046 specific pairs of memory access types.</p>
7047
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7048<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7049<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7050 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7051 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7052 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7053
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7054<ul>
7055 <li><tt>ll</tt>: load-load barrier</li>
7056 <li><tt>ls</tt>: load-store barrier</li>
7057 <li><tt>sl</tt>: store-load barrier</li>
7058 <li><tt>ss</tt>: store-store barrier</li>
7059 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7060</ul>
7061
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7062<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7063<p>This intrinsic causes the system to enforce some ordering constraints upon
7064 the loads and stores of the program. This barrier does not
7065 indicate <em>when</em> any events will occur, it only enforces
7066 an <em>order</em> in which they occur. For any of the specified pairs of load
7067 and store operations (f.ex. load-load, or store-load), all of the first
7068 operations preceding the barrier will complete before any of the second
7069 operations succeeding the barrier begin. Specifically the semantics for each
7070 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7071
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7072<ul>
7073 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7074 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7075 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7076 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7077 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7078 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7079 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7080 load after the barrier begins.</li>
7081</ul>
7082
7083<p>These semantics are applied with a logical "and" behavior when more than one
7084 is enabled in a single memory barrier intrinsic.</p>
7085
7086<p>Backends may implement stronger barriers than those requested when they do
7087 not support as fine grained a barrier as requested. Some architectures do
7088 not need all types of barriers and on such architectures, these become
7089 noops.</p>
7090
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7091<h5>Example:</h5>
7092<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7093%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7094%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7095 store i32 4, %ptr
7096
7097%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7098 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7099 <i>; guarantee the above finishes</i>
7100 store i32 8, %ptr <i>; before this begins</i>
7101</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7102
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7103</div>
7104
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7105<!-- _______________________________________________________________________ -->
7106<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7107 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7108</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7109
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7110<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7111
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7112<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7113<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7114 any integer bit width and for different address spaces. Not all targets
7115 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7116
7117<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7118 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7119 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7120 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7121 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]7122</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7123
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7124<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7125<p>This loads a value in memory and compares it to a given value. If they are
7126 equal, it stores a new value into the memory.</p>
7127
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7128<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7129<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7130 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7131 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7132 this integer type. While any bit width integer may be used, targets may only
7133 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7134
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7135<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7136<p>This entire intrinsic must be executed atomically. It first loads the value
7137 in memory pointed to by <tt>ptr</tt> and compares it with the
7138 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7139 memory. The loaded value is yielded in all cases. This provides the
7140 equivalent of an atomic compare-and-swap operation within the SSA
7141 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7142
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7143<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7144<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7145%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7146%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7147 store i32 4, %ptr
7148
7149%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7150%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7151 <i>; yields {i32}:result1 = 4</i>
7152%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7153%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7154
7155%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7156%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7157 <i>; yields {i32}:result2 = 8</i>
7158%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7159
7160%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7161</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7162
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7163</div>
7164
7165<!-- _______________________________________________________________________ -->
7166<div class="doc_subsubsection">
7167 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7168</div>
7169<div class="doc_text">
7170<h5>Syntax:</h5>
7171
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7172<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7173 integer bit width. Not all targets support all bit widths however.</p>
7174
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7175<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7176 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7177 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7178 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7179 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]7180</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7181
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7182<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7183<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7184 the value from memory. It then stores the value in <tt>val</tt> in the memory
7185 at <tt>ptr</tt>.</p>
7186
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7187<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7188<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7189 the <tt>val</tt> argument and the result must be integers of the same bit
7190 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7191 integer type. The targets may only lower integer representations they
7192 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7193
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7194<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7195<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7196 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7197 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7198
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7199<h5>Examples:</h5>
7200<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7201%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7202%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7203 store i32 4, %ptr
7204
7205%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7206%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7207 <i>; yields {i32}:result1 = 4</i>
7208%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7209%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7210
7211%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7212%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7213 <i>; yields {i32}:result2 = 8</i>
7214
7215%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7216%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7217</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7218
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7219</div>
7220
7221<!-- _______________________________________________________________________ -->
7222<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7223 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7224
7225</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7226
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7227<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7228
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7229<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7230<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7231 any integer bit width. Not all targets support all bit widths however.</p>
7232
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7233<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7234 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7235 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7236 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7237 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]7238</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7239
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7240<h5>Overview:</h5>
7241<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7242 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7243
7244<h5>Arguments:</h5>
7245<p>The intrinsic takes two arguments, the first a pointer to an integer value
7246 and the second an integer value. The result is also an integer value. These
7247 integer types can have any bit width, but they must all have the same bit
7248 width. The targets may only lower integer representations they support.</p>
7249
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7250<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7251<p>This intrinsic does a series of operations atomically. It first loads the
7252 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7253 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]7254
7255<h5>Examples:</h5>
7256<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7257%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7258%ptr = bitcast i8* %mallocP to i32*
7259 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7260%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7261 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7262%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7263 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7264%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7265 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7266%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7267</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7268
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7269</div>
7270
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7271<!-- _______________________________________________________________________ -->
7272<div class="doc_subsubsection">
7273 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7274
7275</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7276
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7277<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7278
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7279<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7280<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7281 any integer bit width and for different address spaces. Not all targets
7282 support all bit widths however.</p>
7283
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7284<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7285 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7286 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7287 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7288 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]7289</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7290
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7291<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7292<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7293 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7294
7295<h5>Arguments:</h5>
7296<p>The intrinsic takes two arguments, the first a pointer to an integer value
7297 and the second an integer value. The result is also an integer value. These
7298 integer types can have any bit width, but they must all have the same bit
7299 width. The targets may only lower integer representations they support.</p>
7300
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7301<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7302<p>This intrinsic does a series of operations atomically. It first loads the
7303 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7304 result to <tt>ptr</tt>. It yields the original value stored
7305 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7306
7307<h5>Examples:</h5>
7308<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7309%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7310%ptr = bitcast i8* %mallocP to i32*
7311 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7312%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7313 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7314%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7315 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7316%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7317 <i>; yields {i32}:result3 = 2</i>
7318%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7319</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7320
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7321</div>
7322
7323<!-- _______________________________________________________________________ -->
7324<div class="doc_subsubsection">
7325 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7326 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7327 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7328 <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]7329</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7330
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7331<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7332
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7333<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7334<p>These are overloaded intrinsics. You can
7335 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7336 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7337 bit width and for different address spaces. Not all targets support all bit
7338 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7339
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7340<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7341 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7342 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7343 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7344 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]7345</pre>
7346
7347<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7348 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7349 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7350 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7351 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]7352</pre>
7353
7354<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7355 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7356 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7357 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7358 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]7359</pre>
7360
7361<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7362 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7363 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7364 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7365 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]7366</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7367
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7368<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7369<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7370 the value stored in memory at <tt>ptr</tt>. It yields the original value
7371 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7372
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7373<h5>Arguments:</h5>
7374<p>These intrinsics take two arguments, the first a pointer to an integer value
7375 and the second an integer value. The result is also an integer value. These
7376 integer types can have any bit width, but they must all have the same bit
7377 width. The targets may only lower integer representations they support.</p>
7378
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7379<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7380<p>These intrinsics does a series of operations atomically. They first load the
7381 value stored at <tt>ptr</tt>. They then do the bitwise
7382 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7383 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7384
7385<h5>Examples:</h5>
7386<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7387%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7388%ptr = bitcast i8* %mallocP to i32*
7389 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7390%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7391 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7392%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7393 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7394%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7395 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7396%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7397 <i>; yields {i32}:result3 = FF</i>
7398%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7399</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7400
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7401</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7402
7403<!-- _______________________________________________________________________ -->
7404<div class="doc_subsubsection">
7405 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7406 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7407 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7408 <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]7409</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7410
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7411<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7412
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7413<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7414<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7415 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7416 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7417 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7418
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7419<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7420 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7421 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7422 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7423 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]7424</pre>
7425
7426<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7427 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7428 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7429 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7430 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]7431</pre>
7432
7433<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7434 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7435 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7436 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7437 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]7438</pre>
7439
7440<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7441 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7442 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7443 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7444 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]7445</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7446
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7447<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7448<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7449 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7450 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7451
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7452<h5>Arguments:</h5>
7453<p>These intrinsics take two arguments, the first a pointer to an integer value
7454 and the second an integer value. The result is also an integer value. These
7455 integer types can have any bit width, but they must all have the same bit
7456 width. The targets may only lower integer representations they support.</p>
7457
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7458<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7459<p>These intrinsics does a series of operations atomically. They first load the
7460 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7461 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7462 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7463
7464<h5>Examples:</h5>
7465<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7466%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7467%ptr = bitcast i8* %mallocP to i32*
7468 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7469%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7470 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7471%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7472 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7473%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7474 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7475%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7476 <i>; yields {i32}:result3 = 8</i>
7477%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7478</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7479
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7480</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7481
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7482
7483<!-- ======================================================================= -->
7484<div class="doc_subsection">
7485 <a name="int_memorymarkers">Memory Use Markers</a>
7486</div>
7487
7488<div class="doc_text">
7489
7490<p>This class of intrinsics exists to information about the lifetime of memory
7491 objects and ranges where variables are immutable.</p>
7492
7493</div>
7494
7495<!-- _______________________________________________________________________ -->
7496<div class="doc_subsubsection">
7497 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7498</div>
7499
7500<div class="doc_text">
7501
7502<h5>Syntax:</h5>
7503<pre>
7504 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7505</pre>
7506
7507<h5>Overview:</h5>
7508<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7509 object's lifetime.</p>
7510
7511<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7512<p>The first argument is a constant integer representing the size of the
7513 object, or -1 if it is variable sized. The second argument is a pointer to
7514 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7515
7516<h5>Semantics:</h5>
7517<p>This intrinsic indicates that before this point in the code, the value of the
7518 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]7519 never be used and has an undefined value. A load from the pointer that
7520 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7521 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7522
7523</div>
7524
7525<!-- _______________________________________________________________________ -->
7526<div class="doc_subsubsection">
7527 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7528</div>
7529
7530<div class="doc_text">
7531
7532<h5>Syntax:</h5>
7533<pre>
7534 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7535</pre>
7536
7537<h5>Overview:</h5>
7538<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7539 object's lifetime.</p>
7540
7541<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7542<p>The first argument is a constant integer representing the size of the
7543 object, or -1 if it is variable sized. The second argument is a pointer to
7544 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7545
7546<h5>Semantics:</h5>
7547<p>This intrinsic indicates that after this point in the code, the value of the
7548 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7549 never be used and has an undefined value. Any stores into the memory object
7550 following this intrinsic may be removed as dead.
7551
7552</div>
7553
7554<!-- _______________________________________________________________________ -->
7555<div class="doc_subsubsection">
7556 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7557</div>
7558
7559<div class="doc_text">
7560
7561<h5>Syntax:</h5>
7562<pre>
7563 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7564</pre>
7565
7566<h5>Overview:</h5>
7567<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7568 a memory object will not change.</p>
7569
7570<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7571<p>The first argument is a constant integer representing the size of the
7572 object, or -1 if it is variable sized. The second argument is a pointer to
7573 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7574
7575<h5>Semantics:</h5>
7576<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7577 the return value, the referenced memory location is constant and
7578 unchanging.</p>
7579
7580</div>
7581
7582<!-- _______________________________________________________________________ -->
7583<div class="doc_subsubsection">
7584 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7585</div>
7586
7587<div class="doc_text">
7588
7589<h5>Syntax:</h5>
7590<pre>
7591 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7592</pre>
7593
7594<h5>Overview:</h5>
7595<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7596 a memory object are mutable.</p>
7597
7598<h5>Arguments:</h5>
7599<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7600 The second argument is a constant integer representing the size of the
7601 object, or -1 if it is variable sized and the third argument is a pointer
7602 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7603
7604<h5>Semantics:</h5>
7605<p>This intrinsic indicates that the memory is mutable again.</p>
7606
7607</div>
7608
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7609<!-- ======================================================================= -->
7610<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7611 <a name="int_general">General Intrinsics</a>
7612</div>
7613
7614<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7615
7616<p>This class of intrinsics is designed to be generic and has no specific
7617 purpose.</p>
7618
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7619</div>
7620
7621<!-- _______________________________________________________________________ -->
7622<div class="doc_subsubsection">
7623 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7624</div>
7625
7626<div class="doc_text">
7627
7628<h5>Syntax:</h5>
7629<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7630 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]7631</pre>
7632
7633<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7634<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7635
7636<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7637<p>The first argument is a pointer to a value, the second is a pointer to a
7638 global string, the third is a pointer to a global string which is the source
7639 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7640
7641<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7642<p>This intrinsic allows annotation of local variables with arbitrary strings.
7643 This can be useful for special purpose optimizations that want to look for
7644 these annotations. These have no other defined use, they are ignored by code
7645 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7646
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7647</div>
7648
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7649<!-- _______________________________________________________________________ -->
7650<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7651 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7652</div>
7653
7654<div class="doc_text">
7655
7656<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7657<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7658 any integer bit width.</p>
7659
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7660<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7661 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7662 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7663 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7664 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7665 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]7666</pre>
7667
7668<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7669<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7670
7671<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7672<p>The first argument is an integer value (result of some expression), the
7673 second is a pointer to a global string, the third is a pointer to a global
7674 string which is the source file name, and the last argument is the line
7675 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7676
7677<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7678<p>This intrinsic allows annotations to be put on arbitrary expressions with
7679 arbitrary strings. This can be useful for special purpose optimizations that
7680 want to look for these annotations. These have no other defined use, they
7681 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7682
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7683</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7684
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7685<!-- _______________________________________________________________________ -->
7686<div class="doc_subsubsection">
7687 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7688</div>
7689
7690<div class="doc_text">
7691
7692<h5>Syntax:</h5>
7693<pre>
7694 declare void @llvm.trap()
7695</pre>
7696
7697<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7698<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7699
7700<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7701<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7702
7703<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7704<p>This intrinsics is lowered to the target dependent trap instruction. If the
7705 target does not have a trap instruction, this intrinsic will be lowered to
7706 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7707
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7708</div>
7709
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7710<!-- _______________________________________________________________________ -->
7711<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7712 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7713</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7714
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7715<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7716
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7717<h5>Syntax:</h5>
7718<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7719 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7720</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7721
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7722<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7723<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7724 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7725 ensure that it is placed on the stack before local variables.</p>
7726
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7727<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7728<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7729 arguments. The first argument is the value loaded from the stack
7730 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7731 that has enough space to hold the value of the guard.</p>
7732
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7733<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7734<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7735 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7736 stack. This is to ensure that if a local variable on the stack is
7737 overwritten, it will destroy the value of the guard. When the function exits,
7738 the guard on the stack is checked against the original guard. If they're
7739 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7740 function.</p>
7741
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7742</div>
7743
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7744<!-- _______________________________________________________________________ -->
7745<div class="doc_subsubsection">
7746 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7747</div>
7748
7749<div class="doc_text">
7750
7751<h5>Syntax:</h5>
7752<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7753 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7754 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7755</pre>
7756
7757<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7758<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7759 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7760 operation like memcpy will either overflow a buffer that corresponds to
7761 an object, or b) to determine that a runtime check for overflow isn't
7762 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7763 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7764
7765<h5>Arguments:</h5>
7766<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7767 argument is a pointer to or into the <tt>object</tt>. The second argument
7768 is a boolean 0 or 1. This argument determines whether you want the
7769 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7770 1, variables are not allowed.</p>
7771
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7772<h5>Semantics:</h5>
7773<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7774 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7775 (depending on the <tt>type</tt> argument if the size cannot be determined
7776 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7777
7778</div>
7779
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7780<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7781<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7782<address>
7783 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7785 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7787
7788 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7789 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7790 Last modified: $Date$
7791</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7792
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7793</body>
7794</html>