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gerrit-public.fairphone.software / toolchain / llvm-project / 2f1ae06c4591203da84c91363c71a5af02d0ebab / . / llvm / docs / LangRef.html
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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>
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>
Bill Wendling7f4a3362009-11-02 00:24:16 +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>
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>
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
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1286 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1287 (double).</dd>
1288
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1289 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1290 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1291 <i>size</i>.</dd>
1292
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1293 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1294 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1295 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1296
1297 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1298 <dd>This specifies a set of native integer widths for the target CPU
1299 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1300 "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]1301 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1302 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1303</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1304
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1305<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1306 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1307 specifications in the <tt>datalayout</tt> keyword. The default specifications
1308 are given in this list:</p>
1309
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1310<ul>
1311 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1312 <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]1313 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1314 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1315 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1316 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1317 <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]1318 alignment of 64-bits</li>
1319 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1320 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1321 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1322 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1323 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1324 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1325</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1326
1327<p>When LLVM is determining the alignment for a given type, it uses the
1328 following rules:</p>
1329
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1330<ol>
1331 <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]1332 specification is used.</li>
1333
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1334 <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]1335 smallest integer type that is larger than the bitwidth of the sought type
1336 is used. If none of the specifications are larger than the bitwidth then
1337 the the largest integer type is used. For example, given the default
1338 specifications above, the i7 type will use the alignment of i8 (next
1339 largest) while both i65 and i256 will use the alignment of i64 (largest
1340 specified).</li>
1341
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1342 <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]1343 largest vector type that is smaller than the sought vector type will be
1344 used as a fall back. This happens because &lt;128 x double&gt; can be
1345 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1346</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1347
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1348</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1349
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1350<!-- ======================================================================= -->
1351<div class="doc_subsection">
1352 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1353</div>
1354
1355<div class="doc_text">
1356
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1357<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1358with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1359is undefined. Pointer values are associated with address ranges
1360according to the following rules:</p>
1361
1362<ul>
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1363 <li>A pointer value formed from a
1364 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1365 is associated with the addresses associated with the first operand
1366 of the <tt>getelementptr</tt>.</li>
1367 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1368 range of the variable's storage.</li>
1369 <li>The result value of an allocation instruction is associated with
1370 the address range of the allocated storage.</li>
1371 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1372 no address.</li>
1373 <li>A pointer value formed by an
1374 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1375 address ranges of all pointer values that contribute (directly or
1376 indirectly) to the computation of the pointer's value.</li>
1377 <li>The result value of a
1378 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1379 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1380 <li>An integer constant other than zero or a pointer value returned
1381 from a function not defined within LLVM may be associated with address
1382 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1383 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1384 allocated by mechanisms provided by LLVM.</li>
1385 </ul>
1386
1387<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1388<tt><a href="#i_load">load</a></tt> merely indicates the size and
1389alignment of the memory from which to load, as well as the
1390interpretation of the value. The first operand of a
1391<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1392and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1393
1394<p>Consequently, type-based alias analysis, aka TBAA, aka
1395<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1396LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1397additional information which specialized optimization passes may use
1398to implement type-based alias analysis.</p>
1399
1400</div>
1401
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1402<!-- ======================================================================= -->
1403<div class="doc_subsection">
1404 <a name="volatile">Volatile Memory Accesses</a>
1405</div>
1406
1407<div class="doc_text">
1408
1409<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1410href="#i_store"><tt>store</tt></a>s, and <a
1411href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1412The optimizers must not change the number of volatile operations or change their
1413order of execution relative to other volatile operations. The optimizers
1414<i>may</i> change the order of volatile operations relative to non-volatile
1415operations. This is not Java's "volatile" and has no cross-thread
1416synchronization behavior.</p>
1417
1418</div>
1419
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1420<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1421<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1422<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1423
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1424<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1425
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1426<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1427 intermediate representation. Being typed enables a number of optimizations
1428 to be performed on the intermediate representation directly, without having
1429 to do extra analyses on the side before the transformation. A strong type
1430 system makes it easier to read the generated code and enables novel analyses
1431 and transformations that are not feasible to perform on normal three address
1432 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1433
1434</div>
1435
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1436<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1437<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1438Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1439
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1440<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1441
1442<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1443
1444<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1445 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1446 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1447 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1448 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1449 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1450 </tr>
1451 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1452 <td><a href="#t_floating">floating point</a></td>
1453 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1454 </tr>
1455 <tr>
1456 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1457 <td><a href="#t_integer">integer</a>,
1458 <a href="#t_floating">floating point</a>,
1459 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1460 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1461 <a href="#t_struct">structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1462 <a href="#t_union">union</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1463 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1464 <a href="#t_label">label</a>,
1465 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1466 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1467 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1468 <tr>
1469 <td><a href="#t_primitive">primitive</a></td>
1470 <td><a href="#t_label">label</a>,
1471 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1472 <a href="#t_floating">floating point</a>,
1473 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1474 </tr>
1475 <tr>
1476 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1477 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1478 <a href="#t_function">function</a>,
1479 <a href="#t_pointer">pointer</a>,
1480 <a href="#t_struct">structure</a>,
1481 <a href="#t_pstruct">packed structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1482 <a href="#t_union">union</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1483 <a href="#t_vector">vector</a>,
1484 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1485 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1486 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1487 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1488</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1489
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1490<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1491 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1492 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1493
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1494</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1495
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1496<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1497<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1498
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1499<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1500
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1501<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1502 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1503
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1504</div>
1505
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1506<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1507<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1508
1509<div class="doc_text">
1510
1511<h5>Overview:</h5>
1512<p>The integer type is a very simple type that simply specifies an arbitrary
1513 bit width for the integer type desired. Any bit width from 1 bit to
1514 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1515
1516<h5>Syntax:</h5>
1517<pre>
1518 iN
1519</pre>
1520
1521<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1522 value.</p>
1523
1524<h5>Examples:</h5>
1525<table class="layout">
1526 <tr class="layout">
1527 <td class="left"><tt>i1</tt></td>
1528 <td class="left">a single-bit integer.</td>
1529 </tr>
1530 <tr class="layout">
1531 <td class="left"><tt>i32</tt></td>
1532 <td class="left">a 32-bit integer.</td>
1533 </tr>
1534 <tr class="layout">
1535 <td class="left"><tt>i1942652</tt></td>
1536 <td class="left">a really big integer of over 1 million bits.</td>
1537 </tr>
1538</table>
1539
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1540</div>
1541
1542<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1543<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1544
1545<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1546
1547<table>
1548 <tbody>
1549 <tr><th>Type</th><th>Description</th></tr>
1550 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1551 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1552 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1553 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1554 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1555 </tbody>
1556</table>
1557
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1558</div>
1559
1560<!-- _______________________________________________________________________ -->
1561<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1562
1563<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1564
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1565<h5>Overview:</h5>
1566<p>The void type does not represent any value and has no size.</p>
1567
1568<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1569<pre>
1570 void
1571</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1572
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1573</div>
1574
1575<!-- _______________________________________________________________________ -->
1576<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1577
1578<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1579
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1580<h5>Overview:</h5>
1581<p>The label type represents code labels.</p>
1582
1583<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1584<pre>
1585 label
1586</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1587
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1588</div>
1589
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1590<!-- _______________________________________________________________________ -->
1591<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1592
1593<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1594
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1595<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1596<p>The metadata type represents embedded metadata. No derived types may be
1597 created from metadata except for <a href="#t_function">function</a>
1598 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1599
1600<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1601<pre>
1602 metadata
1603</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1604
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1605</div>
1606
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1607
1608<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1609<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1610
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1611<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1612
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1613<p>The real power in LLVM comes from the derived types in the system. This is
1614 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1615 useful types. Each of these types contain one or more element types which
1616 may be a primitive type, or another derived type. For example, it is
1617 possible to have a two dimensional array, using an array as the element type
1618 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1619
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1620
1621</div>
1622
1623<!-- _______________________________________________________________________ -->
1624<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1625
1626<div class="doc_text">
1627
1628<p>Aggregate Types are a subset of derived types that can contain multiple
1629 member types. <a href="#t_array">Arrays</a>,
1630 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1631 <a href="#t_union">unions</a> are aggregate types.</p>
1632
1633</div>
1634
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1635</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1636
1637<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1638<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1639
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1640<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1641
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1642<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1643<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1644 sequentially in memory. The array type requires a size (number of elements)
1645 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1646
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1647<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1648<pre>
1649 [&lt;# elements&gt; x &lt;elementtype&gt;]
1650</pre>
1651
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1652<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1653 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1654
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1655<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1656<table class="layout">
1657 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1658 <td class="left"><tt>[40 x i32]</tt></td>
1659 <td class="left">Array of 40 32-bit integer values.</td>
1660 </tr>
1661 <tr class="layout">
1662 <td class="left"><tt>[41 x i32]</tt></td>
1663 <td class="left">Array of 41 32-bit integer values.</td>
1664 </tr>
1665 <tr class="layout">
1666 <td class="left"><tt>[4 x i8]</tt></td>
1667 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1668 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1669</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1670<p>Here are some examples of multidimensional arrays:</p>
1671<table class="layout">
1672 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1673 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1674 <td class="left">3x4 array of 32-bit integer values.</td>
1675 </tr>
1676 <tr class="layout">
1677 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1678 <td class="left">12x10 array of single precision floating point values.</td>
1679 </tr>
1680 <tr class="layout">
1681 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1682 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1683 </tr>
1684</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1685
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1686<p>There is no restriction on indexing beyond the end of the array implied by
1687 a static type (though there are restrictions on indexing beyond the bounds
1688 of an allocated object in some cases). This means that single-dimension
1689 'variable sized array' addressing can be implemented in LLVM with a zero
1690 length array type. An implementation of 'pascal style arrays' in LLVM could
1691 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1692
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1693</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1694
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1695<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1696<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1697
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1698<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1699
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1700<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1701<p>The function type can be thought of as a function signature. It consists of
1702 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]1703 function type is a scalar type, a void type, a struct type, or a union
1704 type. If the return type is a struct type then all struct elements must be
1705 of first class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1706
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1707<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1708<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1709 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1710</pre>
1711
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1712<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]1713 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1714 which indicates that the function takes a variable number of arguments.
1715 Variable argument functions can access their arguments with
1716 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1717 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1718 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1719
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1720<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1721<table class="layout">
1722 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1723 <td class="left"><tt>i32 (i32)</tt></td>
1724 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1725 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1726 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1727 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1728 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1729 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1730 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1731 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1732 </td>
1733 </tr><tr class="layout">
1734 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1735 <td class="left">A vararg function that takes at least one
1736 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1737 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1738 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1739 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1740 </tr><tr class="layout">
1741 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1742 <td class="left">A function taking an <tt>i32</tt>, returning a
1743 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1744 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1745 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1746</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1747
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1748</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1749
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1750<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1751<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1752
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1753<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1754
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1755<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1756<p>The structure type is used to represent a collection of data members together
1757 in memory. The packing of the field types is defined to match the ABI of the
1758 underlying processor. The elements of a structure may be any type that has a
1759 size.</p>
1760
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1761<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1762 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1763 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1764 Structures in registers are accessed using the
1765 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1766 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1767<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1768<pre>
1769 { &lt;type list&gt; }
1770</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1771
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1772<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1773<table class="layout">
1774 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1775 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1776 <td class="left">A triple of three <tt>i32</tt> values</td>
1777 </tr><tr class="layout">
1778 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1779 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1780 second element is a <a href="#t_pointer">pointer</a> to a
1781 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1782 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1783 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1784</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1785
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1786</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1787
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1788<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1789<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1790</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1791
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1792<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1793
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1794<h5>Overview:</h5>
1795<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1796 together in memory. There is no padding between fields. Further, the
1797 alignment of a packed structure is 1 byte. The elements of a packed
1798 structure may be any type that has a size.</p>
1799
1800<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1801 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1802 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1803
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1804<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1805<pre>
1806 &lt; { &lt;type list&gt; } &gt;
1807</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1808
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1809<h5>Examples:</h5>
1810<table class="layout">
1811 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1812 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1813 <td class="left">A triple of three <tt>i32</tt> values</td>
1814 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1815 <td class="left">
1816<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1817 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1818 second element is a <a href="#t_pointer">pointer</a> to a
1819 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1820 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1821 </tr>
1822</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1823
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1824</div>
1825
1826<!-- _______________________________________________________________________ -->
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1827<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1828
1829<div class="doc_text">
1830
1831<h5>Overview:</h5>
1832<p>A union type describes an object with size and alignment suitable for
1833 an object of any one of a given set of types (also known as an "untagged"
1834 union). It is similar in concept and usage to a
1835 <a href="#t_struct">struct</a>, except that all members of the union
1836 have an offset of zero. The elements of a union may be any type that has a
1837 size. Unions must have at least one member - empty unions are not allowed.
1838 </p>
1839
1840<p>The size of the union as a whole will be the size of its largest member,
1841 and the alignment requirements of the union as a whole will be the largest
1842 alignment requirement of any member.</p>
1843
Dan Gohman1ad14992010-02-25 16:51:31 +0000[diff] [blame]1844<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]1845 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1846 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1847 Since all members are at offset zero, the getelementptr instruction does
1848 not affect the address, only the type of the resulting pointer.</p>
1849
1850<h5>Syntax:</h5>
1851<pre>
1852 union { &lt;type list&gt; }
1853</pre>
1854
1855<h5>Examples:</h5>
1856<table class="layout">
1857 <tr class="layout">
1858 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1859 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1860 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1861 </tr><tr class="layout">
1862 <td class="left">
1863 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1864 <td class="left">A union, where the first element is a <tt>float</tt> and the
1865 second element is a <a href="#t_pointer">pointer</a> to a
1866 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1867 an <tt>i32</tt>.</td>
1868 </tr>
1869</table>
1870
1871</div>
1872
1873<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1874<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1875
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1876<div class="doc_text">
1877
1878<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1879<p>The pointer type is used to specify memory locations.
1880 Pointers are commonly used to reference objects in memory.</p>
1881
1882<p>Pointer types may have an optional address space attribute defining the
1883 numbered address space where the pointed-to object resides. The default
1884 address space is number zero. The semantics of non-zero address
1885 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1886
1887<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1888 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1889
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1890<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1891<pre>
1892 &lt;type&gt; *
1893</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1894
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1895<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1896<table class="layout">
1897 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1898 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1899 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1900 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1901 </tr>
1902 <tr class="layout">
1903 <td class="left"><tt>i32 (i32 *) *</tt></td>
1904 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1905 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1906 <tt>i32</tt>.</td>
1907 </tr>
1908 <tr class="layout">
1909 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1910 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1911 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1912 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1913</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1914
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1915</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1916
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1917<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1918<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1919
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1920<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1921
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1922<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1923<p>A vector type is a simple derived type that represents a vector of elements.
1924 Vector types are used when multiple primitive data are operated in parallel
1925 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1926 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1927 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1928
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1929<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1930<pre>
1931 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1932</pre>
1933
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1934<p>The number of elements is a constant integer value; elementtype may be any
1935 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1936
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1937<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1938<table class="layout">
1939 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1940 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1941 <td class="left">Vector of 4 32-bit integer values.</td>
1942 </tr>
1943 <tr class="layout">
1944 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1945 <td class="left">Vector of 8 32-bit floating-point values.</td>
1946 </tr>
1947 <tr class="layout">
1948 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1949 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1950 </tr>
1951</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1952
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1953</div>
1954
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1955<!-- _______________________________________________________________________ -->
1956<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1957<div class="doc_text">
1958
1959<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1960<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1961 corresponds (for example) to the C notion of a forward declared structure
1962 type. In LLVM, opaque types can eventually be resolved to any type (not just
1963 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1964
1965<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1966<pre>
1967 opaque
1968</pre>
1969
1970<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1971<table class="layout">
1972 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1973 <td class="left"><tt>opaque</tt></td>
1974 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1975 </tr>
1976</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1977
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1978</div>
1979
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1980<!-- ======================================================================= -->
1981<div class="doc_subsection">
1982 <a name="t_uprefs">Type Up-references</a>
1983</div>
1984
1985<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1986
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1987<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1988<p>An "up reference" allows you to refer to a lexically enclosing type without
1989 requiring it to have a name. For instance, a structure declaration may
1990 contain a pointer to any of the types it is lexically a member of. Example
1991 of up references (with their equivalent as named type declarations)
1992 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1993
1994<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1995 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1996 { \2 }* %y = type { %y }*
1997 \1* %z = type %z*
1998</pre>
1999
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2000<p>An up reference is needed by the asmprinter for printing out cyclic types
2001 when there is no declared name for a type in the cycle. Because the
2002 asmprinter does not want to print out an infinite type string, it needs a
2003 syntax to handle recursive types that have no names (all names are optional
2004 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2005
2006<h5>Syntax:</h5>
2007<pre>
2008 \&lt;level&gt;
2009</pre>
2010
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2011<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]2012
2013<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2014<table class="layout">
2015 <tr class="layout">
2016 <td class="left"><tt>\1*</tt></td>
2017 <td class="left">Self-referential pointer.</td>
2018 </tr>
2019 <tr class="layout">
2020 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2021 <td class="left">Recursive structure where the upref refers to the out-most
2022 structure.</td>
2023 </tr>
2024</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2025
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2026</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2027
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2028<!-- *********************************************************************** -->
2029<div class="doc_section"> <a name="constants">Constants</a> </div>
2030<!-- *********************************************************************** -->
2031
2032<div class="doc_text">
2033
2034<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2035 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2036
2037</div>
2038
2039<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]2040<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2041
2042<div class="doc_text">
2043
2044<dl>
2045 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2046 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2047 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2048
2049 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2050 <dd>Standard integers (such as '4') are constants of
2051 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2052 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2053
2054 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2055 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2056 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2057 notation (see below). The assembler requires the exact decimal value of a
2058 floating-point constant. For example, the assembler accepts 1.25 but
2059 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2060 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2061
2062 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2063 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2064 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2065</dl>
2066
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2067<p>The one non-intuitive notation for constants is the hexadecimal form of
2068 floating point constants. For example, the form '<tt>double
2069 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2070 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2071 constants are required (and the only time that they are generated by the
2072 disassembler) is when a floating point constant must be emitted but it cannot
2073 be represented as a decimal floating point number in a reasonable number of
2074 digits. For example, NaN's, infinities, and other special values are
2075 represented in their IEEE hexadecimal format so that assembly and disassembly
2076 do not cause any bits to change in the constants.</p>
2077
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2078<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2079 represented using the 16-digit form shown above (which matches the IEEE754
2080 representation for double); float values must, however, be exactly
2081 representable as IEE754 single precision. Hexadecimal format is always used
2082 for long double, and there are three forms of long double. The 80-bit format
2083 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2084 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2085 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2086 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2087 currently supported target uses this format. Long doubles will only work if
2088 they match the long double format on your target. All hexadecimal formats
2089 are big-endian (sign bit at the left).</p>
2090
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2091</div>
2092
2093<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2094<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2095<a name="aggregateconstants"></a> <!-- old anchor -->
2096<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2097</div>
2098
2099<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2100
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2101<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2102 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2103
2104<dl>
2105 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2106 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2107 type definitions (a comma separated list of elements, surrounded by braces
2108 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2109 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2110 Structure constants must have <a href="#t_struct">structure type</a>, and
2111 the number and types of elements must match those specified by the
2112 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2113
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2114 <dt><b>Union constants</b></dt>
2115 <dd>Union constants are represented with notation similar to a structure with
2116 a single element - that is, a single typed element surrounded
2117 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2118 <a href="#t_union">union type</a> can be initialized with a single-element
2119 struct as long as the type of the struct element matches the type of
2120 one of the union members.</dd>
2121
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2122 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2123 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2124 definitions (a comma separated list of elements, surrounded by square
2125 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2126 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2127 the number and types of elements must match those specified by the
2128 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2129
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2130 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2131 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2132 definitions (a comma separated list of elements, surrounded by
2133 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2134 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2135 have <a href="#t_vector">vector type</a>, and the number and types of
2136 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2137
2138 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2139 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2140 value to zero of <em>any</em> type, including scalar and
2141 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2142 This is often used to avoid having to print large zero initializers
2143 (e.g. for large arrays) and is always exactly equivalent to using explicit
2144 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2145
2146 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2147 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2148 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2149 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2150 be interpreted as part of the instruction stream, metadata is a place to
2151 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2152</dl>
2153
2154</div>
2155
2156<!-- ======================================================================= -->
2157<div class="doc_subsection">
2158 <a name="globalconstants">Global Variable and Function Addresses</a>
2159</div>
2160
2161<div class="doc_text">
2162
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2163<p>The addresses of <a href="#globalvars">global variables</a>
2164 and <a href="#functionstructure">functions</a> are always implicitly valid
2165 (link-time) constants. These constants are explicitly referenced when
2166 the <a href="#identifiers">identifier for the global</a> is used and always
2167 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2168 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2169
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2170<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2171<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2172@X = global i32 17
2173@Y = global i32 42
2174@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2175</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2176</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2177
2178</div>
2179
2180<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2181<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2182<div class="doc_text">
2183
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2184<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]2185 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2186 Undefined values may be of any type (other than label or void) and be used
2187 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2188
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2189<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2190 program is well defined no matter what value is used. This gives the
2191 compiler more freedom to optimize. Here are some examples of (potentially
2192 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2193
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2194
2195<div class="doc_code">
2196<pre>
2197 %A = add %X, undef
2198 %B = sub %X, undef
2199 %C = xor %X, undef
2200Safe:
2201 %A = undef
2202 %B = undef
2203 %C = undef
2204</pre>
2205</div>
2206
2207<p>This is safe because all of the output bits are affected by the undef bits.
2208Any output bit can have a zero or one depending on the input bits.</p>
2209
2210<div class="doc_code">
2211<pre>
2212 %A = or %X, undef
2213 %B = and %X, undef
2214Safe:
2215 %A = -1
2216 %B = 0
2217Unsafe:
2218 %A = undef
2219 %B = undef
2220</pre>
2221</div>
2222
2223<p>These logical operations have bits that are not always affected by the input.
2224For example, if "%X" has a zero bit, then the output of the 'and' operation will
2225always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2226such, 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]2227However, it is safe to assume that all bits of the undef could be 0, and
2228optimize the and to 0. Likewise, it is safe to assume that all the bits of
2229the 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]2230-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2231
2232<div class="doc_code">
2233<pre>
2234 %A = select undef, %X, %Y
2235 %B = select undef, 42, %Y
2236 %C = select %X, %Y, undef
2237Safe:
2238 %A = %X (or %Y)
2239 %B = 42 (or %Y)
2240 %C = %Y
2241Unsafe:
2242 %A = undef
2243 %B = undef
2244 %C = undef
2245</pre>
2246</div>
2247
2248<p>This set of examples show that undefined select (and conditional branch)
2249conditions can go "either way" but they have to come from one of the two
2250operands. In the %A example, if %X and %Y were both known to have a clear low
2251bit, then %A would have to have a cleared low bit. However, in the %C example,
2252the optimizer is allowed to assume that the undef operand could be the same as
2253%Y, allowing the whole select to be eliminated.</p>
2254
2255
2256<div class="doc_code">
2257<pre>
2258 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2259
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2260 %B = undef
2261 %C = xor %B, %B
2262
2263 %D = undef
2264 %E = icmp lt %D, 4
2265 %F = icmp gte %D, 4
2266
2267Safe:
2268 %A = undef
2269 %B = undef
2270 %C = undef
2271 %D = undef
2272 %E = undef
2273 %F = undef
2274</pre>
2275</div>
2276
2277<p>This example points out that two undef operands are not necessarily the same.
2278This can be surprising to people (and also matches C semantics) where they
2279assume that "X^X" is always zero, even if X is undef. This isn't true for a
2280number of reasons, but the short answer is that an undef "variable" can
2281arbitrarily change its value over its "live range". This is true because the
2282"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2283logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2284so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2285to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2286would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2287
2288<div class="doc_code">
2289<pre>
2290 %A = fdiv undef, %X
2291 %B = fdiv %X, undef
2292Safe:
2293 %A = undef
2294b: unreachable
2295</pre>
2296</div>
2297
2298<p>These examples show the crucial difference between an <em>undefined
2299value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2300allowed to have an arbitrary bit-pattern. This means that the %A operation
2301can be constant folded to undef because the undef could be an SNaN, and fdiv is
2302not (currently) defined on SNaN's. However, in the second example, we can make
2303a more aggressive assumption: because the undef is allowed to be an arbitrary
2304value, 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]2305has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2306does not execute at all. This allows us to delete the divide and all code after
2307it: since the undefined operation "can't happen", the optimizer can assume that
2308it occurs in dead code.
2309</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2310
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2311<div class="doc_code">
2312<pre>
2313a: store undef -> %X
2314b: store %X -> undef
2315Safe:
2316a: &lt;deleted&gt;
2317b: unreachable
2318</pre>
2319</div>
2320
2321<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2322can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2323overwritten with bits that happen to match what was already there. However, a
2324store "to" an undefined location could clobber arbitrary memory, therefore, it
2325has undefined behavior.</p>
2326
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2327</div>
2328
2329<!-- ======================================================================= -->
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2330<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2331<div class="doc_text">
2332
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2333<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2334 instead of representing an unspecified bit pattern, they represent the
2335 fact that an instruction or constant expression which cannot evoke side
2336 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2337 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2338
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame^]2339<p>There is currently no way of representing a trap value in the IR; they
2340 only exist when produced by instructions such as
2341 <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]2342
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame^]2343<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2344
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame^]2345<p>
2346<ul>
2347<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2348 their operands.</li>
2349
2350<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2351 to their dynamic predecessor basic block.</li>
2352
2353<li>Function arguments depend on the corresponding actual argument values in
2354 the dynamic callers of their functions.</li>
2355
2356<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2357 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2358 control back to them.</li>
2359
2360<li>Non-volatile loads and stores depend on the most recent stores to all of the
2361 referenced memory addresses, following the order in the IR
2362 (including loads and stores implied by intrinsics such as
2363 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2364
2365<!-- FIXME: padding in the middle of a struct -->
2366
2367<!-- TODO: In the case of multiple threads, this only applies to loads and
2368 stores from the same thread as the store, or which are sequenced after the
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2369 store by synchronization. -->
2370
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame^]2371<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2372
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame^]2373<li>An instruction with externally visible side effects depends on the most
2374 recent preceding instruction with externally visible side effects, following
2375 the order in the IR. (This includes volatile loads and stores.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2376
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame^]2377<li>An instruction <i>control-depends</i> on a <a href="#i_br"><tt>br</tt></a>,
2378 <a href="#i_switch"><tt>switch</tt></a>, or
2379 <a href="#i_indirectbr"><tt>indirectbr</tt></a> if the <tt>br</tt>,
2380 <tt>switch</tt>, or <tt>indirectbr</tt> has multiple successors and the
2381 instruction is always executed when control transfers to one of the
2382 successors, and may not be executed when control is transfered to
2383 another.</li>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2384
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame^]2385<!-- FIXME: invoke, unwind, exceptions -->
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>
Reid Spencer59b6b7d2006-11-08 01:11:31 +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
Reid Spencer59b6b7d2006-11-08 01:11:31 +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
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
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
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
Reid Spencer753163d2007-07-31 14:40:14 +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
Reid Spencer51b07252006-11-09 23:03:26 +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
Reid Spencer51b07252006-11-09 23:03:26 +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
Reid Spencer51b07252006-11-09 23:03:26 +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
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2532 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
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
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
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
2549 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]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
Robert Bocchino7e97a6d2006-01-10 19:31:34 +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
2559 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2560 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2561
2562 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
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
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
Robert Bocchinof72fdfe2006-01-15 20:48:27 +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
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
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2577 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2578 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2579 be any of the <a href="#binaryops">binary</a>
2580 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2581 on operands are the same as those for the corresponding instruction
2582 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2583</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2584
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2585</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2586
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2587<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2588<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2589<!-- *********************************************************************** -->
2590
2591<!-- ======================================================================= -->
2592<div class="doc_subsection">
2593<a name="inlineasm">Inline Assembler Expressions</a>
2594</div>
2595
2596<div class="doc_text">
2597
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2598<p>LLVM supports inline assembler expressions (as opposed
2599 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2600 a special value. This value represents the inline assembler as a string
2601 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2602 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2603 expression has side effects, and a flag indicating whether the function
2604 containing the asm needs to align its stack conservatively. An example
2605 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2606
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2607<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2608<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2609i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2610</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2611</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2612
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2613<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2614 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2615 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2616
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2617<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2618<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2619%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]2620</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2621</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2622
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2623<p>Inline asms with side effects not visible in the constraint list must be
2624 marked as having side effects. This is done through the use of the
2625 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2626
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2627<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2628<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2629call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2630</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2631</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2632
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2633<p>In some cases inline asms will contain code that will not work unless the
2634 stack is aligned in some way, such as calls or SSE instructions on x86,
2635 yet will not contain code that does that alignment within the asm.
2636 The compiler should make conservative assumptions about what the asm might
2637 contain and should generate its usual stack alignment code in the prologue
2638 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2639
2640<div class="doc_code">
2641<pre>
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2642call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2643</pre>
2644</div>
2645
2646<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2647 first.</p>
2648
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2649<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2650 documented here. Constraints on what can be done (e.g. duplication, moving,
2651 etc need to be documented). This is probably best done by reference to
2652 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2653</div>
2654
2655<div class="doc_subsubsection">
2656<a name="inlineasm_md">Inline Asm Metadata</a>
2657</div>
2658
2659<div class="doc_text">
2660
2661<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2662 attached to it that contains a constant integer. If present, the code
2663 generator will use the integer as the location cookie value when report
2664 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2665 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2666 source code that produced it. For example:</p>
2667
2668<div class="doc_code">
2669<pre>
2670call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2671...
2672!42 = !{ i32 1234567 }
2673</pre>
2674</div>
2675
2676<p>It is up to the front-end to make sense of the magic numbers it places in the
2677 IR.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2678
2679</div>
2680
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2681<!-- ======================================================================= -->
2682<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2683 Strings</a>
2684</div>
2685
2686<div class="doc_text">
2687
2688<p>LLVM IR allows metadata to be attached to instructions in the program that
2689 can convey extra information about the code to the optimizers and code
2690 generator. One example application of metadata is source-level debug
2691 information. There are two metadata primitives: strings and nodes. All
2692 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2693 preceding exclamation point ('<tt>!</tt>').</p>
2694
2695<p>A metadata string is a string surrounded by double quotes. It can contain
2696 any character by escaping non-printable characters with "\xx" where "xx" is
2697 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2698
2699<p>Metadata nodes are represented with notation similar to structure constants
2700 (a comma separated list of elements, surrounded by braces and preceded by an
2701 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2702 10}</tt>". Metadata nodes can have any values as their operand.</p>
2703
2704<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2705 metadata nodes, which can be looked up in the module symbol table. For
2706 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2707
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2708<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2709 function is using two metadata arguments.
2710
2711 <div class="doc_code">
2712 <pre>
2713 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2714 </pre>
2715 </div></p>
2716
2717<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2718 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2719
2720 <div class="doc_code">
2721 <pre>
2722 %indvar.next = add i64 %indvar, 1, !dbg !21
2723 </pre>
2724 </div></p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2725</div>
2726
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2727
2728<!-- *********************************************************************** -->
2729<div class="doc_section">
2730 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2731</div>
2732<!-- *********************************************************************** -->
2733
2734<p>LLVM has a number of "magic" global variables that contain data that affect
2735code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2736of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2737section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2738by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2739
2740<!-- ======================================================================= -->
2741<div class="doc_subsection">
2742<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2743</div>
2744
2745<div class="doc_text">
2746
2747<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2748href="#linkage_appending">appending linkage</a>. This array contains a list of
2749pointers to global variables and functions which may optionally have a pointer
2750cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2751
2752<pre>
2753 @X = global i8 4
2754 @Y = global i32 123
2755
2756 @llvm.used = appending global [2 x i8*] [
2757 i8* @X,
2758 i8* bitcast (i32* @Y to i8*)
2759 ], section "llvm.metadata"
2760</pre>
2761
2762<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2763compiler, assembler, and linker are required to treat the symbol as if there is
2764a reference to the global that it cannot see. For example, if a variable has
2765internal linkage and no references other than that from the <tt>@llvm.used</tt>
2766list, it cannot be deleted. This is commonly used to represent references from
2767inline asms and other things the compiler cannot "see", and corresponds to
2768"attribute((used))" in GNU C.</p>
2769
2770<p>On some targets, the code generator must emit a directive to the assembler or
2771object file to prevent the assembler and linker from molesting the symbol.</p>
2772
2773</div>
2774
2775<!-- ======================================================================= -->
2776<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2777<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2778</div>
2779
2780<div class="doc_text">
2781
2782<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2783<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2784touching the symbol. On targets that support it, this allows an intelligent
2785linker to optimize references to the symbol without being impeded as it would be
2786by <tt>@llvm.used</tt>.</p>
2787
2788<p>This is a rare construct that should only be used in rare circumstances, and
2789should not be exposed to source languages.</p>
2790
2791</div>
2792
2793<!-- ======================================================================= -->
2794<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2795<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2796</div>
2797
2798<div class="doc_text">
2799
2800<p>TODO: Describe this.</p>
2801
2802</div>
2803
2804<!-- ======================================================================= -->
2805<div class="doc_subsection">
2806<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2807</div>
2808
2809<div class="doc_text">
2810
2811<p>TODO: Describe this.</p>
2812
2813</div>
2814
2815
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2816<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2817<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2818<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2819
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2820<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2821
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2822<p>The LLVM instruction set consists of several different classifications of
2823 instructions: <a href="#terminators">terminator
2824 instructions</a>, <a href="#binaryops">binary instructions</a>,
2825 <a href="#bitwiseops">bitwise binary instructions</a>,
2826 <a href="#memoryops">memory instructions</a>, and
2827 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2828
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2829</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2830
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2831<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2832<div class="doc_subsection"> <a name="terminators">Terminator
2833Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2834
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2835<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2836
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2837<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2838 in a program ends with a "Terminator" instruction, which indicates which
2839 block should be executed after the current block is finished. These
2840 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2841 control flow, not values (the one exception being the
2842 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2843
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2844<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2845 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2846 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2847 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2848 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2849 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2850 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2851 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2852
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2853</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2854
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2855<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2856<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2857Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2858
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2859<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2860
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2861<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2862<pre>
2863 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]2864 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2865</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2866
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2867<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2868<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2869 a value) from a function back to the caller.</p>
2870
2871<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2872 value and then causes control flow, and one that just causes control flow to
2873 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2874
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2875<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2876<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2877 return value. The type of the return value must be a
2878 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2879
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2880<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2881 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2882 value or a return value with a type that does not match its type, or if it
2883 has a void return type and contains a '<tt>ret</tt>' instruction with a
2884 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2885
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2886<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2887<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2888 the calling function's context. If the caller is a
2889 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2890 instruction after the call. If the caller was an
2891 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2892 the beginning of the "normal" destination block. If the instruction returns
2893 a value, that value shall set the call or invoke instruction's return
2894 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2895
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2897<pre>
2898 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2899 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2900 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]2901</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2902
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2903</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2904<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2905<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2906
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2907<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2908
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2909<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2910<pre>
2911 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]2912</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2913
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2914<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2915<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2916 different basic block in the current function. There are two forms of this
2917 instruction, corresponding to a conditional branch and an unconditional
2918 branch.</p>
2919
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2920<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2921<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2922 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2923 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2924 target.</p>
2925
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2926<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2927<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2928 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2929 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2930 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2931
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2932<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2933<pre>
2934Test:
2935 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2936 br i1 %cond, label %IfEqual, label %IfUnequal
2937IfEqual:
2938 <a href="#i_ret">ret</a> i32 1
2939IfUnequal:
2940 <a href="#i_ret">ret</a> i32 0
2941</pre>
2942
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2943</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2944
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2945<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2946<div class="doc_subsubsection">
2947 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2948</div>
2949
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2950<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2951
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2952<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2953<pre>
2954 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2955</pre>
2956
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2957<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2958<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]2959 several different places. It is a generalization of the '<tt>br</tt>'
2960 instruction, allowing a branch to occur to one of many possible
2961 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2962
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2963<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2964<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2965 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2966 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2967 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2968
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2969<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2970<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2971 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2972 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2973 transferred to the corresponding destination; otherwise, control flow is
2974 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2975
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2976<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2977<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2978 <tt>switch</tt> instruction, this instruction may be code generated in
2979 different ways. For example, it could be generated as a series of chained
2980 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2981
2982<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2983<pre>
2984 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2985 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2986 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2987
2988 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2989 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2990
2991 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2992 switch i32 %val, label %otherwise [ i32 0, label %onzero
2993 i32 1, label %onone
2994 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2995</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2996
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2997</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2998
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2999
3000<!-- _______________________________________________________________________ -->
3001<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3002 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3003</div>
3004
3005<div class="doc_text">
3006
3007<h5>Syntax:</h5>
3008<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3009 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]3010</pre>
3011
3012<h5>Overview:</h5>
3013
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3014<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3015 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3016 "<tt>address</tt>". Address must be derived from a <a
3017 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3018
3019<h5>Arguments:</h5>
3020
3021<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3022 rest of the arguments indicate the full set of possible destinations that the
3023 address may point to. Blocks are allowed to occur multiple times in the
3024 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3025
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3026<p>This destination list is required so that dataflow analysis has an accurate
3027 understanding of the CFG.</p>
3028
3029<h5>Semantics:</h5>
3030
3031<p>Control transfers to the block specified in the address argument. All
3032 possible destination blocks must be listed in the label list, otherwise this
3033 instruction has undefined behavior. This implies that jumps to labels
3034 defined in other functions have undefined behavior as well.</p>
3035
3036<h5>Implementation:</h5>
3037
3038<p>This is typically implemented with a jump through a register.</p>
3039
3040<h5>Example:</h5>
3041<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3042 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3043</pre>
3044
3045</div>
3046
3047
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3048<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3049<div class="doc_subsubsection">
3050 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3051</div>
3052
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3053<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3054
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3055<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3056<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3057 &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]3058 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3059</pre>
3060
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3061<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3062<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3063 function, with the possibility of control flow transfer to either the
3064 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3065 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3066 control flow will return to the "normal" label. If the callee (or any
3067 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3068 instruction, control is interrupted and continued at the dynamically nearest
3069 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3070
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3071<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3072<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3073
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3074<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3075 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3076 convention</a> the call should use. If none is specified, the call
3077 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3078
3079 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3080 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3081 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3082
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3083 <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]3084 function value being invoked. In most cases, this is a direct function
3085 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3086 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3087
3088 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3089 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3090
3091 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3092 signature argument types and parameter attributes. All arguments must be
3093 of <a href="#t_firstclass">first class</a> type. If the function
3094 signature indicates the function accepts a variable number of arguments,
3095 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3096
3097 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3098 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3099
3100 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3101 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3102
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3103 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3104 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3105 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3106</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3107
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3108<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3109<p>This instruction is designed to operate as a standard
3110 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3111 primary difference is that it establishes an association with a label, which
3112 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3113
3114<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3115 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3116 exception. Additionally, this is important for implementation of
3117 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3118
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3119<p>For the purposes of the SSA form, the definition of the value returned by the
3120 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3121 block to the "normal" label. If the callee unwinds then no return value is
3122 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3123
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3124<p>Note that the code generator does not yet completely support unwind, and
3125that the invoke/unwind semantics are likely to change in future versions.</p>
3126
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3127<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3128<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3129 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3130 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3131 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3132 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3133</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3134
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3135</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3136
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3137<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3138
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3139<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3140Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3141
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3142<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3143
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3144<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3145<pre>
3146 unwind
3147</pre>
3148
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3149<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3150<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3151 at the first callee in the dynamic call stack which used
3152 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3153 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3154
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3155<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3156<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3157 immediately halt. The dynamic call stack is then searched for the
3158 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3159 Once found, execution continues at the "exceptional" destination block
3160 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3161 instruction in the dynamic call chain, undefined behavior results.</p>
3162
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3163<p>Note that the code generator does not yet completely support unwind, and
3164that the invoke/unwind semantics are likely to change in future versions.</p>
3165
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3166</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3167
3168<!-- _______________________________________________________________________ -->
3169
3170<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3171Instruction</a> </div>
3172
3173<div class="doc_text">
3174
3175<h5>Syntax:</h5>
3176<pre>
3177 unreachable
3178</pre>
3179
3180<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3181<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3182 instruction is used to inform the optimizer that a particular portion of the
3183 code is not reachable. This can be used to indicate that the code after a
3184 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3185
3186<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3187<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3188
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3189</div>
3190
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3191<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3192<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3193
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3194<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3195
3196<p>Binary operators are used to do most of the computation in a program. They
3197 require two operands of the same type, execute an operation on them, and
3198 produce a single value. The operands might represent multiple data, as is
3199 the case with the <a href="#t_vector">vector</a> data type. The result value
3200 has the same type as its operands.</p>
3201
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3202<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3203
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3204</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3205
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3206<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3207<div class="doc_subsubsection">
3208 <a name="i_add">'<tt>add</tt>' Instruction</a>
3209</div>
3210
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3211<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3212
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3213<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3214<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3215 &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]3216 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3217 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3218 &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]3219</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3220
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3221<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3222<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3223
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3224<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3225<p>The two arguments to the '<tt>add</tt>' instruction must
3226 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3227 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3228
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3229<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3230<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3231
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3232<p>If the sum has unsigned overflow, the result returned is the mathematical
3233 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]3234
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3235<p>Because LLVM integers use a two's complement representation, this instruction
3236 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3237
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3238<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3239 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3240 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3241 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3242 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3243
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3244<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3245<pre>
3246 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3247</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3248
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3249</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3250
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3251<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3252<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3253 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3254</div>
3255
3256<div class="doc_text">
3257
3258<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3259<pre>
3260 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3261</pre>
3262
3263<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3264<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3265
3266<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3267<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3268 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3269 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3270
3271<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3272<p>The value produced is the floating point sum of the two operands.</p>
3273
3274<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3275<pre>
3276 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3277</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3278
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3279</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3280
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3281<!-- _______________________________________________________________________ -->
3282<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3283 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3284</div>
3285
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3286<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3287
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3288<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3289<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3290 &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]3291 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3292 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3293 &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]3294</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3295
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3296<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3297<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3298 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3299
3300<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3301 '<tt>neg</tt>' instruction present in most other intermediate
3302 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3303
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3304<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3305<p>The two arguments to the '<tt>sub</tt>' instruction must
3306 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3307 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3308
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3309<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3310<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3311
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3312<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3313 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3314 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3315
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3316<p>Because LLVM integers use a two's complement representation, this instruction
3317 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3318
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3319<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3320 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3321 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3322 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3323 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3324
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3325<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3326<pre>
3327 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3328 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3329</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3330
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3331</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3332
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3333<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3334<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3335 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3336</div>
3337
3338<div class="doc_text">
3339
3340<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3341<pre>
3342 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3343</pre>
3344
3345<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3346<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3347 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3348
3349<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3350 '<tt>fneg</tt>' instruction present in most other intermediate
3351 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3352
3353<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3354<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3355 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3356 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3357
3358<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3359<p>The value produced is the floating point difference of the two operands.</p>
3360
3361<h5>Example:</h5>
3362<pre>
3363 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3364 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3365</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3366
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3367</div>
3368
3369<!-- _______________________________________________________________________ -->
3370<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3371 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3372</div>
3373
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3374<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3375
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3376<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3377<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3378 &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]3379 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3380 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3381 &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]3382</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3383
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3384<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3385<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3386
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3387<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3388<p>The two arguments to the '<tt>mul</tt>' instruction must
3389 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3390 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3391
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3392<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3393<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3394
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3395<p>If the result of the multiplication has unsigned overflow, the result
3396 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3397 width of the result.</p>
3398
3399<p>Because LLVM integers use a two's complement representation, and the result
3400 is the same width as the operands, this instruction returns the correct
3401 result for both signed and unsigned integers. If a full product
3402 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3403 be sign-extended or zero-extended as appropriate to the width of the full
3404 product.</p>
3405
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3406<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3407 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3408 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3409 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3410 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3411
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3412<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3413<pre>
3414 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3415</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3416
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3417</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3418
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3419<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3420<div class="doc_subsubsection">
3421 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3422</div>
3423
3424<div class="doc_text">
3425
3426<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3427<pre>
3428 &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]3429</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3430
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3431<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3432<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3433
3434<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3435<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3436 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3437 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3438
3439<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3440<p>The value produced is the floating point product of the two operands.</p>
3441
3442<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3443<pre>
3444 &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]3445</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3446
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3447</div>
3448
3449<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3450<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3451</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3452
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3453<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3454
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3455<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3456<pre>
3457 &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]3458</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3459
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3460<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3461<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3462
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3463<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3464<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3465 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3466 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3467
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3468<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3469<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3470
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3471<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3472 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3473
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3474<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3475
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3476<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3477<pre>
3478 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</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</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3482
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3483<!-- _______________________________________________________________________ -->
3484<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3485</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3486
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3487<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3488
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3489<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3490<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3491 &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]3492 &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]3493</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3494
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3495<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3496<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3497
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3498<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3499<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3500 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3501 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3502
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3503<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3504<p>The value produced is the signed integer quotient of the two operands rounded
3505 towards zero.</p>
3506
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3507<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3508 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3509
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3510<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3511 undefined behavior; this is a rare case, but can occur, for example, by doing
3512 a 32-bit division of -2147483648 by -1.</p>
3513
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3514<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3515 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3516 be rounded or if overflow would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3517
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3518<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3519<pre>
3520 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3521</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3522
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3523</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3524
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3525<!-- _______________________________________________________________________ -->
3526<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3527Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3528
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3529<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3530
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3531<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3532<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3533 &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]3534</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3535
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3536<h5>Overview:</h5>
3537<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3538
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3539<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3540<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3541 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3542 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3543
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3544<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3545<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3546
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3547<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3548<pre>
3549 &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]3550</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3551
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3552</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3553
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3554<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3555<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3556</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3557
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3558<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3559
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3560<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3561<pre>
3562 &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]3563</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3564
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3565<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3566<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3567 division of its two arguments.</p>
3568
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3569<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3570<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3571 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3572 values. Both arguments must have identical types.</p>
3573
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3574<h5>Semantics:</h5>
3575<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3576 This instruction always performs an unsigned division to get the
3577 remainder.</p>
3578
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3579<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3580 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3581
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3582<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3583
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3584<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3585<pre>
3586 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3587</pre>
3588
3589</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3590
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3591<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3592<div class="doc_subsubsection">
3593 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3594</div>
3595
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3596<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3597
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3598<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3599<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3600 &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]3601</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3602
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3603<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3604<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3605 division of its two operands. This instruction can also take
3606 <a href="#t_vector">vector</a> versions of the values in which case the
3607 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3608
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3609<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3610<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3611 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3612 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3613
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3614<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3615<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3616 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3617 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3618 a value. For more information about the difference,
3619 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3620 Math Forum</a>. For a table of how this is implemented in various languages,
3621 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3622 Wikipedia: modulo operation</a>.</p>
3623
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3624<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3625 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3626
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3627<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3628 Overflow also leads to undefined behavior; this is a rare case, but can
3629 occur, for example, by taking the remainder of a 32-bit division of
3630 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3631 lets srem be implemented using instructions that return both the result of
3632 the division and the remainder.)</p>
3633
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3634<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3635<pre>
3636 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3637</pre>
3638
3639</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3640
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3641<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3642<div class="doc_subsubsection">
3643 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3644
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3645<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3646
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3647<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3648<pre>
3649 &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]3650</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3651
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3652<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3653<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3654 its two operands.</p>
3655
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3656<h5>Arguments:</h5>
3657<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3658 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3659 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3660
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3661<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3662<p>This instruction returns the <i>remainder</i> of a division. The remainder
3663 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3664
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3665<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3666<pre>
3667 &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]3668</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3669
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3670</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3671
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3672<!-- ======================================================================= -->
3673<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3674Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3675
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3676<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3677
3678<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3679 program. They are generally very efficient instructions and can commonly be
3680 strength reduced from other instructions. They require two operands of the
3681 same type, execute an operation on them, and produce a single value. The
3682 resulting value is the same type as its operands.</p>
3683
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3684</div>
3685
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3686<!-- _______________________________________________________________________ -->
3687<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3688Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3689
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3690<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3691
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3692<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3693<pre>
3694 &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]3695</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3696
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3697<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3698<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3699 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3700
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3701<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3702<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3703 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3704 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3705
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3706<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3707<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3708 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3709 is (statically or dynamically) negative or equal to or larger than the number
3710 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3711 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3712 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3713
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3714<h5>Example:</h5>
3715<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3716 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3717 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3718 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3719 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3720 &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]3721</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3722
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3723</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3724
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3725<!-- _______________________________________________________________________ -->
3726<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3727Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3728
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3729<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3730
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3731<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3732<pre>
3733 &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]3734</pre>
3735
3736<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3737<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3738 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3739
3740<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3741<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3742 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3743 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3744
3745<h5>Semantics:</h5>
3746<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3747 significant bits of the result will be filled with zero bits after the shift.
3748 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3749 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3750 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3751 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3752
3753<h5>Example:</h5>
3754<pre>
3755 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3756 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3757 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3758 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3759 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3760 &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]3761</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3762
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3763</div>
3764
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3765<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3766<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3767Instruction</a> </div>
3768<div class="doc_text">
3769
3770<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3771<pre>
3772 &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]3773</pre>
3774
3775<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3776<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3777 operand shifted to the right a specified number of bits with sign
3778 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3779
3780<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3781<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3782 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3783 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3784
3785<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3786<p>This instruction always performs an arithmetic shift right operation, The
3787 most significant bits of the result will be filled with the sign bit
3788 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3789 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3790 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3791 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3792
3793<h5>Example:</h5>
3794<pre>
3795 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3796 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3797 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3798 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3799 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3800 &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]3801</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3802
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3803</div>
3804
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3805<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3806<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3807Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3808
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3809<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3810
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3811<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3812<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3813 &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]3814</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3815
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3816<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3817<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3818 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3819
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3820<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3821<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3822 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3823 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3824
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3825<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3826<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3827
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3828<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3829 <tbody>
3830 <tr>
3831 <td>In0</td>
3832 <td>In1</td>
3833 <td>Out</td>
3834 </tr>
3835 <tr>
3836 <td>0</td>
3837 <td>0</td>
3838 <td>0</td>
3839 </tr>
3840 <tr>
3841 <td>0</td>
3842 <td>1</td>
3843 <td>0</td>
3844 </tr>
3845 <tr>
3846 <td>1</td>
3847 <td>0</td>
3848 <td>0</td>
3849 </tr>
3850 <tr>
3851 <td>1</td>
3852 <td>1</td>
3853 <td>1</td>
3854 </tr>
3855 </tbody>
3856</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3857
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3858<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3859<pre>
3860 &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]3861 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3862 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3863</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3864</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3865<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3866<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3867
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3868<div class="doc_text">
3869
3870<h5>Syntax:</h5>
3871<pre>
3872 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3873</pre>
3874
3875<h5>Overview:</h5>
3876<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3877 two operands.</p>
3878
3879<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3880<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3881 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3882 values. Both arguments must have identical types.</p>
3883
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3884<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3885<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3886
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3887<table border="1" cellspacing="0" cellpadding="4">
3888 <tbody>
3889 <tr>
3890 <td>In0</td>
3891 <td>In1</td>
3892 <td>Out</td>
3893 </tr>
3894 <tr>
3895 <td>0</td>
3896 <td>0</td>
3897 <td>0</td>
3898 </tr>
3899 <tr>
3900 <td>0</td>
3901 <td>1</td>
3902 <td>1</td>
3903 </tr>
3904 <tr>
3905 <td>1</td>
3906 <td>0</td>
3907 <td>1</td>
3908 </tr>
3909 <tr>
3910 <td>1</td>
3911 <td>1</td>
3912 <td>1</td>
3913 </tr>
3914 </tbody>
3915</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3916
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3917<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3918<pre>
3919 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3920 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3921 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3922</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3923
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3924</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3925
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3926<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3927<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3928Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3929
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3930<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3931
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3932<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3933<pre>
3934 &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]3935</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3936
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3937<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3938<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3939 its two operands. The <tt>xor</tt> is used to implement the "one's
3940 complement" operation, which is the "~" operator in C.</p>
3941
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3942<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3943<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3944 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3945 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3946
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3947<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3948<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3949
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3950<table border="1" cellspacing="0" cellpadding="4">
3951 <tbody>
3952 <tr>
3953 <td>In0</td>
3954 <td>In1</td>
3955 <td>Out</td>
3956 </tr>
3957 <tr>
3958 <td>0</td>
3959 <td>0</td>
3960 <td>0</td>
3961 </tr>
3962 <tr>
3963 <td>0</td>
3964 <td>1</td>
3965 <td>1</td>
3966 </tr>
3967 <tr>
3968 <td>1</td>
3969 <td>0</td>
3970 <td>1</td>
3971 </tr>
3972 <tr>
3973 <td>1</td>
3974 <td>1</td>
3975 <td>0</td>
3976 </tr>
3977 </tbody>
3978</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3979
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3980<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3981<pre>
3982 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3983 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3984 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3985 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3986</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3987
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3988</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3989
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3990<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3991<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3992 <a name="vectorops">Vector Operations</a>
3993</div>
3994
3995<div class="doc_text">
3996
3997<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3998 target-independent manner. These instructions cover the element-access and
3999 vector-specific operations needed to process vectors effectively. While LLVM
4000 does directly support these vector operations, many sophisticated algorithms
4001 will want to use target-specific intrinsics to take full advantage of a
4002 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4003
4004</div>
4005
4006<!-- _______________________________________________________________________ -->
4007<div class="doc_subsubsection">
4008 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4009</div>
4010
4011<div class="doc_text">
4012
4013<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4014<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4015 &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]4016</pre>
4017
4018<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4019<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4020 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4021
4022
4023<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4024<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4025 of <a href="#t_vector">vector</a> type. The second operand is an index
4026 indicating the position from which to extract the element. The index may be
4027 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4028
4029<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4030<p>The result is a scalar of the same type as the element type of
4031 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4032 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4033 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4034
4035<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4036<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4037 &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]4038</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4039
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4040</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4041
4042<!-- _______________________________________________________________________ -->
4043<div class="doc_subsubsection">
4044 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4045</div>
4046
4047<div class="doc_text">
4048
4049<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4050<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4051 &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]4052</pre>
4053
4054<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4055<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4056 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4057
4058<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4059<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4060 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4061 whose type must equal the element type of the first operand. The third
4062 operand is an index indicating the position at which to insert the value.
4063 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4064
4065<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4066<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4067 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4068 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4069 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4070
4071<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4072<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4073 &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]4074</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4075
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4076</div>
4077
4078<!-- _______________________________________________________________________ -->
4079<div class="doc_subsubsection">
4080 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4081</div>
4082
4083<div class="doc_text">
4084
4085<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4086<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4087 &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]4088</pre>
4089
4090<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4091<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4092 from two input vectors, returning a vector with the same element type as the
4093 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4094
4095<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4096<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4097 with types that match each other. The third argument is a shuffle mask whose
4098 element type is always 'i32'. The result of the instruction is a vector
4099 whose length is the same as the shuffle mask and whose element type is the
4100 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4101
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4102<p>The shuffle mask operand is required to be a constant vector with either
4103 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4104
4105<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4106<p>The elements of the two input vectors are numbered from left to right across
4107 both of the vectors. The shuffle mask operand specifies, for each element of
4108 the result vector, which element of the two input vectors the result element
4109 gets. The element selector may be undef (meaning "don't care") and the
4110 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4111
4112<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4113<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4114 &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]4115 &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]4116 &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]4117 &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]4118 &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]4119 &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]4120 &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]4121 &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]4122</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4123
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4124</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4125
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4126<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4127<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4128 <a name="aggregateops">Aggregate Operations</a>
4129</div>
4130
4131<div class="doc_text">
4132
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4133<p>LLVM supports several instructions for working with
4134 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4135
4136</div>
4137
4138<!-- _______________________________________________________________________ -->
4139<div class="doc_subsubsection">
4140 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4141</div>
4142
4143<div class="doc_text">
4144
4145<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4146<pre>
4147 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4148</pre>
4149
4150<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4151<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4152 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4153
4154<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4155<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4156 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4157 <a href="#t_array">array</a> type. The operands are constant indices to
4158 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4159 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4160
4161<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4162<p>The result is the value at the position in the aggregate specified by the
4163 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4164
4165<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4166<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4167 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4168</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4169
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4170</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4171
4172<!-- _______________________________________________________________________ -->
4173<div class="doc_subsubsection">
4174 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4175</div>
4176
4177<div class="doc_text">
4178
4179<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4180<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4181 &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]4182</pre>
4183
4184<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4185<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4186 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4187
4188<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4189<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4190 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4191 <a href="#t_array">array</a> type. The second operand is a first-class
4192 value to insert. The following operands are constant indices indicating
4193 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]4194 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4195 value to insert must have the same type as the value identified by the
4196 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4197
4198<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4199<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4200 that of <tt>val</tt> except that the value at the position specified by the
4201 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4202
4203<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4204<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4205 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4206 %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]4207</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4208
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4209</div>
4210
4211
4212<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4213<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4214 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4215</div>
4216
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4217<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4218
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4219<p>A key design point of an SSA-based representation is how it represents
4220 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4221 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4222 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4223
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4224</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4225
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4226<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4227<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4228 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4229</div>
4230
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4231<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4232
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4233<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4234<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4235 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4236</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4237
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4238<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4239<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4240 currently executing function, to be automatically released when this function
4241 returns to its caller. The object is always allocated in the generic address
4242 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4243
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4244<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4245<p>The '<tt>alloca</tt>' instruction
4246 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4247 runtime stack, returning a pointer of the appropriate type to the program.
4248 If "NumElements" is specified, it is the number of elements allocated,
4249 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4250 specified, the value result of the allocation is guaranteed to be aligned to
4251 at least that boundary. If not specified, or if zero, the target can choose
4252 to align the allocation on any convenient boundary compatible with the
4253 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4254
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4255<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4256
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4257<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4258<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4259 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4260 memory is automatically released when the function returns. The
4261 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4262 variables that must have an address available. When the function returns
4263 (either with the <tt><a href="#i_ret">ret</a></tt>
4264 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4265 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4266
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4267<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4268<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4269 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4270 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4271 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4272 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4273</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4274
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4275</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4276
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4277<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4278<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4279Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4280
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4281<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4282
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4283<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4284<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4285 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4286 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4287 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4288</pre>
4289
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4290<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4291<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4292
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4293<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4294<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4295 from which to load. The pointer must point to
4296 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4297 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4298 number or order of execution of this <tt>load</tt> with other <a
4299 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4300
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4301<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4302 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]4303 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4304 alignment for the target. It is the responsibility of the code emitter to
4305 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4306 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4307 produce less efficient code. An alignment of 1 is always safe.</p>
4308
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4309<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4310 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4311 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4312 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4313 and code generator that this load is not expected to be reused in the cache.
4314 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4315 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4316
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4317<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4318<p>The location of memory pointed to is loaded. If the value being loaded is of
4319 scalar type then the number of bytes read does not exceed the minimum number
4320 of bytes needed to hold all bits of the type. For example, loading an
4321 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4322 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4323 is undefined if the value was not originally written using a store of the
4324 same type.</p>
4325
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4326<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4327<pre>
4328 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4329 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4330 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4331</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4332
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4333</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4334
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4335<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4336<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4337Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4338
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4339<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4340
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4341<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4342<pre>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4343 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4344 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]4345</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4346
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4347<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4348<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4349
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4350<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4351<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4352 and an address at which to store it. The type of the
4353 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4354 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4355 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4356 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4357 order of execution of this <tt>store</tt> with other <a
4358 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4359
4360<p>The optional constant "align" argument specifies the alignment of the
4361 operation (that is, the alignment of the memory address). A value of 0 or an
4362 omitted "align" argument means that the operation has the preferential
4363 alignment for the target. It is the responsibility of the code emitter to
4364 ensure that the alignment information is correct. Overestimating the
4365 alignment results in an undefined behavior. Underestimating the alignment may
4366 produce less efficient code. An alignment of 1 is always safe.</p>
4367
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4368<p>The optional !nontemporal metadata must reference a single metatadata
4369 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4370 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4371 instruction tells the optimizer and code generator that this load is
4372 not expected to be reused in the cache. The code generator may
4373 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4374 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4375
4376
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4377<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4378<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4379 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4380 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4381 does not exceed the minimum number of bytes needed to hold all bits of the
4382 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4383 writing a value of a type like <tt>i20</tt> with a size that is not an
4384 integral number of bytes, it is unspecified what happens to the extra bits
4385 that do not belong to the type, but they will typically be overwritten.</p>
4386
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4387<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4388<pre>
4389 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4390 store i32 3, i32* %ptr <i>; yields {void}</i>
4391 %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]4392</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4393
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4394</div>
4395
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4396<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4397<div class="doc_subsubsection">
4398 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4399</div>
4400
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4401<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4402
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4403<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4404<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4405 &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]4406 &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]4407</pre>
4408
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4409<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4410<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4411 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4412 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4413
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4414<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4415<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4416 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4417 elements of the aggregate object are indexed. The interpretation of each
4418 index is dependent on the type being indexed into. The first index always
4419 indexes the pointer value given as the first argument, the second index
4420 indexes a value of the type pointed to (not necessarily the value directly
4421 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4422 indexed into must be a pointer value, subsequent types can be arrays,
4423 vectors, structs and unions. Note that subsequent types being indexed into
4424 can never be pointers, since that would require loading the pointer before
4425 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4426
4427<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]4428 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4429 integer <b>constants</b> are allowed. When indexing into an array, pointer
4430 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]4431 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4432
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4433<p>For example, let's consider a C code fragment and how it gets compiled to
4434 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4435
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4436<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4437<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4438struct RT {
4439 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4440 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4441 char C;
4442};
4443struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4444 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4445 double Y;
4446 struct RT Z;
4447};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4448
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4449int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4450 return &amp;s[1].Z.B[5][13];
4451}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4452</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4453</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4454
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4455<p>The LLVM code generated by the GCC frontend is:</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>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4459%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4460%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4461
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4462define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4463entry:
4464 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4465 ret i32* %reg
4466}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4467</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4468</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4469
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4470<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4471<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]4472 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4473 }</tt>' type, a structure. The second index indexes into the third element
4474 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4475 i8 }</tt>' type, another structure. The third index indexes into the second
4476 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4477 array. The two dimensions of the array are subscripted into, yielding an
4478 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4479 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4480
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4481<p>Note that it is perfectly legal to index partially through a structure,
4482 returning a pointer to an inner element. Because of this, the LLVM code for
4483 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4484
4485<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4486 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4487 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4488 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4489 %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]4490 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4491 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4492 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4493 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4494</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4495
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4496<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4497 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4498 base pointer is not an <i>in bounds</i> address of an allocated object,
4499 or if any of the addresses that would be formed by successive addition of
4500 the offsets implied by the indices to the base address with infinitely
4501 precise arithmetic are not an <i>in bounds</i> address of that allocated
4502 object. The <i>in bounds</i> addresses for an allocated object are all
4503 the addresses that point into the object, plus the address one byte past
4504 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4505
4506<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4507 the base address with silently-wrapping two's complement arithmetic, and
4508 the result value of the <tt>getelementptr</tt> may be outside the object
4509 pointed to by the base pointer. The result value may not necessarily be
4510 used to access memory though, even if it happens to point into allocated
4511 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4512 section for more information.</p>
4513
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4514<p>The getelementptr instruction is often confusing. For some more insight into
4515 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4516
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4517<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4518<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4519 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4520 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4521 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4522 %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]4523 <i>; yields i8*:eptr</i>
4524 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4525 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4526 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4527</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4528
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4529</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4530
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4531<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4532<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4533</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4534
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4535<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4536
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4537<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4538 which all take a single operand and a type. They perform various bit
4539 conversions on the operand.</p>
4540
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4541</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4542
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4543<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4544<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4545 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4546</div>
4547<div class="doc_text">
4548
4549<h5>Syntax:</h5>
4550<pre>
4551 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4552</pre>
4553
4554<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4555<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4556 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4557
4558<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4559<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4560 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4561 size and type of the result, which must be
4562 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4563 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4564 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4565
4566<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4567<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4568 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4569 source size must be larger than the destination size, <tt>trunc</tt> cannot
4570 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4571
4572<h5>Example:</h5>
4573<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4574 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4575 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4576 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4577</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4578
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4579</div>
4580
4581<!-- _______________________________________________________________________ -->
4582<div class="doc_subsubsection">
4583 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4584</div>
4585<div class="doc_text">
4586
4587<h5>Syntax:</h5>
4588<pre>
4589 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4590</pre>
4591
4592<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4593<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4594 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4595
4596
4597<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4598<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]4599 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4600 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]4601 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4602 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4603
4604<h5>Semantics:</h5>
4605<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]4606 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4607
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4608<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]4609
4610<h5>Example:</h5>
4611<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4612 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4613 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4614</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4615
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4616</div>
4617
4618<!-- _______________________________________________________________________ -->
4619<div class="doc_subsubsection">
4620 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4621</div>
4622<div class="doc_text">
4623
4624<h5>Syntax:</h5>
4625<pre>
4626 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4627</pre>
4628
4629<h5>Overview:</h5>
4630<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4631
4632<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4633<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]4634 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4635 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]4636 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4637 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4638
4639<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4640<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4641 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4642 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4643
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4644<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]4645
4646<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4647<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4648 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4649 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4650</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4651
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4652</div>
4653
4654<!-- _______________________________________________________________________ -->
4655<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4656 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4657</div>
4658
4659<div class="doc_text">
4660
4661<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4662<pre>
4663 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4664</pre>
4665
4666<h5>Overview:</h5>
4667<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4668 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4669
4670<h5>Arguments:</h5>
4671<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4672 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4673 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]4674 <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]4675 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4676
4677<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4678<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4679 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4680 <a href="#t_floating">floating point</a> type. If the value cannot fit
4681 within the destination type, <tt>ty2</tt>, then the results are
4682 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4683
4684<h5>Example:</h5>
4685<pre>
4686 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4687 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4688</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4689
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4690</div>
4691
4692<!-- _______________________________________________________________________ -->
4693<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4694 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4695</div>
4696<div class="doc_text">
4697
4698<h5>Syntax:</h5>
4699<pre>
4700 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4701</pre>
4702
4703<h5>Overview:</h5>
4704<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]4705 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4706
4707<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4708<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4709 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4710 a <a href="#t_floating">floating point</a> type to cast it to. The source
4711 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4712
4713<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4714<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4715 <a href="#t_floating">floating point</a> type to a larger
4716 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4717 used to make a <i>no-op cast</i> because it always changes bits. Use
4718 <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]4719
4720<h5>Example:</h5>
4721<pre>
4722 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4723 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4724</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4725
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4726</div>
4727
4728<!-- _______________________________________________________________________ -->
4729<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4730 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4731</div>
4732<div class="doc_text">
4733
4734<h5>Syntax:</h5>
4735<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4736 &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]4737</pre>
4738
4739<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4740<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4741 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4742
4743<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4744<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4745 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4746 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4747 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4748 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4749
4750<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4751<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4752 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4753 towards zero) unsigned integer value. If the value cannot fit
4754 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4755
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4756<h5>Example:</h5>
4757<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4758 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4759 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4760 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4761</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4762
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4763</div>
4764
4765<!-- _______________________________________________________________________ -->
4766<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4767 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4768</div>
4769<div class="doc_text">
4770
4771<h5>Syntax:</h5>
4772<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4773 &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]4774</pre>
4775
4776<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4777<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4778 <a href="#t_floating">floating point</a> <tt>value</tt> to
4779 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4780
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4781<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4782<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4783 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4784 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4785 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4786 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4787
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4788<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4789<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4790 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4791 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4792 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4793
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4794<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4795<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4796 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4797 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4798 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4799</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4800
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4801</div>
4802
4803<!-- _______________________________________________________________________ -->
4804<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4805 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4806</div>
4807<div class="doc_text">
4808
4809<h5>Syntax:</h5>
4810<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4811 &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]4812</pre>
4813
4814<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4815<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4816 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4817
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4818<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4819<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]4820 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4821 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4822 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4823 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4824
4825<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4826<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4827 integer quantity and converts it to the corresponding floating point
4828 value. If the value cannot fit in the floating point value, the results are
4829 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4830
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4831<h5>Example:</h5>
4832<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4833 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4834 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4835</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4836
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4837</div>
4838
4839<!-- _______________________________________________________________________ -->
4840<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4841 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4842</div>
4843<div class="doc_text">
4844
4845<h5>Syntax:</h5>
4846<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4847 &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]4848</pre>
4849
4850<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4851<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4852 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4853
4854<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4855<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]4856 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4857 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4858 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4859 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4860
4861<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4862<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4863 quantity and converts it to the corresponding floating point value. If the
4864 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4865
4866<h5>Example:</h5>
4867<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4868 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4869 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4870</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4871
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4872</div>
4873
4874<!-- _______________________________________________________________________ -->
4875<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4876 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4877</div>
4878<div class="doc_text">
4879
4880<h5>Syntax:</h5>
4881<pre>
4882 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4883</pre>
4884
4885<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4886<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4887 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4888
4889<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4890<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4891 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4892 <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]4893
4894<h5>Semantics:</h5>
4895<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4896 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4897 truncating or zero extending that value to the size of the integer type. If
4898 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4899 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4900 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4901 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4902
4903<h5>Example:</h5>
4904<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4905 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4906 %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]4907</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4908
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4909</div>
4910
4911<!-- _______________________________________________________________________ -->
4912<div class="doc_subsubsection">
4913 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4914</div>
4915<div class="doc_text">
4916
4917<h5>Syntax:</h5>
4918<pre>
4919 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4920</pre>
4921
4922<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4923<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4924 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4925
4926<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4927<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4928 value to cast, and a type to cast it to, which must be a
4929 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4930
4931<h5>Semantics:</h5>
4932<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4933 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4934 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4935 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4936 than the size of a pointer then a zero extension is done. If they are the
4937 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4938
4939<h5>Example:</h5>
4940<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4941 %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]4942 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4943 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4944</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4945
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4946</div>
4947
4948<!-- _______________________________________________________________________ -->
4949<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4950 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4951</div>
4952<div class="doc_text">
4953
4954<h5>Syntax:</h5>
4955<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4956 &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]4957</pre>
4958
4959<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4960<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4961 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4962
4963<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4964<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4965 non-aggregate first class value, and a type to cast it to, which must also be
4966 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4967 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4968 identical. If the source type is a pointer, the destination type must also be
4969 a pointer. This instruction supports bitwise conversion of vectors to
4970 integers and to vectors of other types (as long as they have the same
4971 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4972
4973<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4974<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4975 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4976 this conversion. The conversion is done as if the <tt>value</tt> had been
4977 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4978 be converted to other pointer types with this instruction. To convert
4979 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4980 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4981
4982<h5>Example:</h5>
4983<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4984 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4985 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4986 %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]4987</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4988
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4989</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4990
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4991<!-- ======================================================================= -->
4992<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4993
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4994<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4995
4996<p>The instructions in this category are the "miscellaneous" instructions, which
4997 defy better classification.</p>
4998
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4999</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5000
5001<!-- _______________________________________________________________________ -->
5002<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5003</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5004
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5005<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5006
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5007<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5008<pre>
5009 &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]5010</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5011
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5012<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5013<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5014 boolean values based on comparison of its two integer, integer vector, or
5015 pointer operands.</p>
5016
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5017<h5>Arguments:</h5>
5018<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5019 the condition code indicating the kind of comparison to perform. It is not a
5020 value, just a keyword. The possible condition code are:</p>
5021
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5022<ol>
5023 <li><tt>eq</tt>: equal</li>
5024 <li><tt>ne</tt>: not equal </li>
5025 <li><tt>ugt</tt>: unsigned greater than</li>
5026 <li><tt>uge</tt>: unsigned greater or equal</li>
5027 <li><tt>ult</tt>: unsigned less than</li>
5028 <li><tt>ule</tt>: unsigned less or equal</li>
5029 <li><tt>sgt</tt>: signed greater than</li>
5030 <li><tt>sge</tt>: signed greater or equal</li>
5031 <li><tt>slt</tt>: signed less than</li>
5032 <li><tt>sle</tt>: signed less or equal</li>
5033</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5034
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5035<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5036 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5037 typed. They must also be identical types.</p>
5038
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5039<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5040<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5041 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5042 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]5043 result, as follows:</p>
5044
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5045<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5046 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5047 <tt>false</tt> otherwise. No sign interpretation is necessary or
5048 performed.</li>
5049
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5050 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5051 <tt>false</tt> otherwise. No sign interpretation is necessary or
5052 performed.</li>
5053
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5054 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5055 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5056
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5057 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5058 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5059 to <tt>op2</tt>.</li>
5060
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5061 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5062 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5063
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5064 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5065 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5066
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5067 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5068 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5069
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5070 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5071 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5072 to <tt>op2</tt>.</li>
5073
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5074 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5075 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5076
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5077 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5078 <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]5079</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5080
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5081<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5082 values are compared as if they were integers.</p>
5083
5084<p>If the operands are integer vectors, then they are compared element by
5085 element. The result is an <tt>i1</tt> vector with the same number of elements
5086 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5087
5088<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5089<pre>
5090 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5091 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5092 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5093 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5094 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5095 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5096</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5097
5098<p>Note that the code generator does not yet support vector types with
5099 the <tt>icmp</tt> instruction.</p>
5100
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5101</div>
5102
5103<!-- _______________________________________________________________________ -->
5104<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5105</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5106
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5107<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5108
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5109<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5110<pre>
5111 &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]5112</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5113
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5114<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5115<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5116 values based on comparison of its operands.</p>
5117
5118<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]5119(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5120
5121<p>If the operands are floating point vectors, then the result type is a vector
5122 of boolean with the same number of elements as the operands being
5123 compared.</p>
5124
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5125<h5>Arguments:</h5>
5126<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5127 the condition code indicating the kind of comparison to perform. It is not a
5128 value, just a keyword. The possible condition code are:</p>
5129
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5130<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5131 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5132 <li><tt>oeq</tt>: ordered and equal</li>
5133 <li><tt>ogt</tt>: ordered and greater than </li>
5134 <li><tt>oge</tt>: ordered and greater than or equal</li>
5135 <li><tt>olt</tt>: ordered and less than </li>
5136 <li><tt>ole</tt>: ordered and less than or equal</li>
5137 <li><tt>one</tt>: ordered and not equal</li>
5138 <li><tt>ord</tt>: ordered (no nans)</li>
5139 <li><tt>ueq</tt>: unordered or equal</li>
5140 <li><tt>ugt</tt>: unordered or greater than </li>
5141 <li><tt>uge</tt>: unordered or greater than or equal</li>
5142 <li><tt>ult</tt>: unordered or less than </li>
5143 <li><tt>ule</tt>: unordered or less than or equal</li>
5144 <li><tt>une</tt>: unordered or not equal</li>
5145 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5146 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5147</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5148
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5149<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5150 <i>unordered</i> means that either operand may be a QNAN.</p>
5151
5152<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5153 a <a href="#t_floating">floating point</a> type or
5154 a <a href="#t_vector">vector</a> of floating point type. They must have
5155 identical types.</p>
5156
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5157<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5158<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5159 according to the condition code given as <tt>cond</tt>. If the operands are
5160 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5161 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5162 follows:</p>
5163
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5164<ol>
5165 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5166
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5167 <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]5168 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5169
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5170 <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]5171 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5172
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5173 <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]5174 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5175
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5176 <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]5177 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5178
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5179 <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]5180 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5181
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5182 <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]5183 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5184
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5185 <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]5186
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5187 <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]5188 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5189
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5190 <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]5191 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5192
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5193 <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]5194 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5195
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5196 <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]5197 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5198
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5199 <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]5200 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5201
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5202 <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]5203 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5204
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5205 <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]5206
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5207 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5208</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5209
5210<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5211<pre>
5212 &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]5213 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5214 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5215 &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]5216</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5217
5218<p>Note that the code generator does not yet support vector types with
5219 the <tt>fcmp</tt> instruction.</p>
5220
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5221</div>
5222
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5223<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5224<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5225 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5226</div>
5227
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5228<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5229
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5230<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5231<pre>
5232 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5233</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5234
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5235<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5236<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5237 SSA graph representing the function.</p>
5238
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5239<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5240<p>The type of the incoming values is specified with the first type field. After
5241 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5242 one pair for each predecessor basic block of the current block. Only values
5243 of <a href="#t_firstclass">first class</a> type may be used as the value
5244 arguments to the PHI node. Only labels may be used as the label
5245 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5246
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5247<p>There must be no non-phi instructions between the start of a basic block and
5248 the PHI instructions: i.e. PHI instructions must be first in a basic
5249 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5250
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5251<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5252 occur on the edge from the corresponding predecessor block to the current
5253 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5254 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5255
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5256<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5257<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5258 specified by the pair corresponding to the predecessor basic block that
5259 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5260
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5261<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5262<pre>
5263Loop: ; Infinite loop that counts from 0 on up...
5264 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5265 %nextindvar = add i32 %indvar, 1
5266 br label %Loop
5267</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5268
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5269</div>
5270
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5271<!-- _______________________________________________________________________ -->
5272<div class="doc_subsubsection">
5273 <a name="i_select">'<tt>select</tt>' Instruction</a>
5274</div>
5275
5276<div class="doc_text">
5277
5278<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5279<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5280 &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>
5281
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5282 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5283</pre>
5284
5285<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5286<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5287 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5288
5289
5290<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5291<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5292 values indicating the condition, and two values of the
5293 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5294 vectors and the condition is a scalar, then entire vectors are selected, not
5295 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5296
5297<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5298<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5299 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5300
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5301<p>If the condition is a vector of i1, then the value arguments must be vectors
5302 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5303
5304<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5305<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5306 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5307</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5308
5309<p>Note that the code generator does not yet support conditions
5310 with vector type.</p>
5311
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5312</div>
5313
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5314<!-- _______________________________________________________________________ -->
5315<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5316 <a name="i_call">'<tt>call</tt>' Instruction</a>
5317</div>
5318
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5319<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5320
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5321<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5322<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5323 &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]5324</pre>
5325
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5326<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5327<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5328
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5329<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5330<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5331
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5332<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5333 <li>The optional "tail" marker indicates that the callee function does not
5334 access any allocas or varargs in the caller. Note that calls may be
5335 marked "tail" even if they do not occur before
5336 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5337 present, the function call is eligible for tail call optimization,
5338 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5339 optimized into a jump</a>. The code generator may optimize calls marked
5340 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5341 sibling call optimization</a> when the caller and callee have
5342 matching signatures, or 2) forced tail call optimization when the
5343 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5344 <ul>
5345 <li>Caller and callee both have the calling
5346 convention <tt>fastcc</tt>.</li>
5347 <li>The call is in tail position (ret immediately follows call and ret
5348 uses value of call or is void).</li>
5349 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5350 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5351 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5352 constraints are met.</a></li>
5353 </ul>
5354 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5355
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5356 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5357 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5358 defaults to using C calling conventions. The calling convention of the
5359 call must match the calling convention of the target function, or else the
5360 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5361
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5362 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5363 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5364 '<tt>inreg</tt>' attributes are valid here.</li>
5365
5366 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5367 type of the return value. Functions that return no value are marked
5368 <tt><a href="#t_void">void</a></tt>.</li>
5369
5370 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5371 being invoked. The argument types must match the types implied by this
5372 signature. This type can be omitted if the function is not varargs and if
5373 the function type does not return a pointer to a function.</li>
5374
5375 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5376 be invoked. In most cases, this is a direct function invocation, but
5377 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5378 to function value.</li>
5379
5380 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5381 signature argument types and parameter attributes. All arguments must be
5382 of <a href="#t_firstclass">first class</a> type. If the function
5383 signature indicates the function accepts a variable number of arguments,
5384 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5385
5386 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5387 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5388 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5389</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5390
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5391<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5392<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5393 a specified function, with its incoming arguments bound to the specified
5394 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5395 function, control flow continues with the instruction after the function
5396 call, and the return value of the function is bound to the result
5397 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5398
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5399<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5400<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5401 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5402 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5403 %X = tail call i32 @foo() <i>; yields i32</i>
5404 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5405 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5406
5407 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5408 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5409 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5410 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5411 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5412 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5413</pre>
5414
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5415<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5416standard C99 library as being the C99 library functions, and may perform
5417optimizations or generate code for them under that assumption. This is
5418something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5419freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5420
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5421</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5422
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5423<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5424<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5425 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5426</div>
5427
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5428<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5429
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5430<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5431<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5432 &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]5433</pre>
5434
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5435<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5436<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5437 the "variable argument" area of a function call. It is used to implement the
5438 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5439
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5440<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5441<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5442 argument. It returns a value of the specified argument type and increments
5443 the <tt>va_list</tt> to point to the next argument. The actual type
5444 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5445
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5446<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5447<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5448 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5449 to the next argument. For more information, see the variable argument
5450 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5451
5452<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]5453 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5454 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5455
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5456<p><tt>va_arg</tt> is an LLVM instruction instead of
5457 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5458 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5459
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5460<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5461<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5462
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5463<p>Note that the code generator does not yet fully support va_arg on many
5464 targets. Also, it does not currently support va_arg with aggregate types on
5465 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5466
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5467</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5468
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5469<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5470<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5471<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5472
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5473<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5474
5475<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5476 well known names and semantics and are required to follow certain
5477 restrictions. Overall, these intrinsics represent an extension mechanism for
5478 the LLVM language that does not require changing all of the transformations
5479 in LLVM when adding to the language (or the bitcode reader/writer, the
5480 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5481
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5482<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5483 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5484 begin with this prefix. Intrinsic functions must always be external
5485 functions: you cannot define the body of intrinsic functions. Intrinsic
5486 functions may only be used in call or invoke instructions: it is illegal to
5487 take the address of an intrinsic function. Additionally, because intrinsic
5488 functions are part of the LLVM language, it is required if any are added that
5489 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5490
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5491<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5492 family of functions that perform the same operation but on different data
5493 types. Because LLVM can represent over 8 million different integer types,
5494 overloading is used commonly to allow an intrinsic function to operate on any
5495 integer type. One or more of the argument types or the result type can be
5496 overloaded to accept any integer type. Argument types may also be defined as
5497 exactly matching a previous argument's type or the result type. This allows
5498 an intrinsic function which accepts multiple arguments, but needs all of them
5499 to be of the same type, to only be overloaded with respect to a single
5500 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5501
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5502<p>Overloaded intrinsics will have the names of its overloaded argument types
5503 encoded into its function name, each preceded by a period. Only those types
5504 which are overloaded result in a name suffix. Arguments whose type is matched
5505 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5506 can take an integer of any width and returns an integer of exactly the same
5507 integer width. This leads to a family of functions such as
5508 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5509 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5510 suffix is required. Because the argument's type is matched against the return
5511 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5512
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5513<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5514 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5515
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5516</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5517
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5518<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5519<div class="doc_subsection">
5520 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5521</div>
5522
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5523<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5524
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5525<p>Variable argument support is defined in LLVM with
5526 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5527 intrinsic functions. These functions are related to the similarly named
5528 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5529
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5530<p>All of these functions operate on arguments that use a target-specific value
5531 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5532 not define what this type is, so all transformations should be prepared to
5533 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5534
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5535<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]5536 instruction and the variable argument handling intrinsic functions are
5537 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5538
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5539<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5540<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5541define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5542 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5543 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5544 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5545 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5546
5547 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5548 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5549
5550 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5551 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5552 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5553 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5554 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5555
5556 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5557 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5558 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5559}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5560
5561declare void @llvm.va_start(i8*)
5562declare void @llvm.va_copy(i8*, i8*)
5563declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5564</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5565</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5566
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5567</div>
5568
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5569<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5570<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5571 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5572</div>
5573
5574
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5575<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5576
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5577<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5578<pre>
5579 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5580</pre>
5581
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5582<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5583<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5584 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]5585
5586<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5587<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]5588
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5589<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5590<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]5591 macro available in C. In a target-dependent way, it initializes
5592 the <tt>va_list</tt> element to which the argument points, so that the next
5593 call to <tt>va_arg</tt> will produce the first variable argument passed to
5594 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5595 need to know the last argument of the function as the compiler can figure
5596 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5597
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5598</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5599
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5600<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5601<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5602 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5603</div>
5604
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5605<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5606
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5607<h5>Syntax:</h5>
5608<pre>
5609 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5610</pre>
5611
5612<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5613<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5614 which has been initialized previously
5615 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5616 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5617
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5618<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5619<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]5620
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5621<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5622<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]5623 macro available in C. In a target-dependent way, it destroys
5624 the <tt>va_list</tt> element to which the argument points. Calls
5625 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5626 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5627 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5628
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5629</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5630
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5631<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5632<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5633 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5634</div>
5635
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5636<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5637
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5638<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5639<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5640 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5641</pre>
5642
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5643<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5644<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5645 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5646
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5647<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5648<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]5649 The second argument is a pointer to a <tt>va_list</tt> element to copy
5650 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5651
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5652<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5653<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]5654 macro available in C. In a target-dependent way, it copies the
5655 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5656 element. This intrinsic is necessary because
5657 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5658 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5659
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5660</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5661
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5662<!-- ======================================================================= -->
5663<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5664 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5665</div>
5666
5667<div class="doc_text">
5668
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5669<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5670Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5671intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5672roots on the stack</a>, as well as garbage collector implementations that
5673require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5674barriers. Front-ends for type-safe garbage collected languages should generate
5675these intrinsics to make use of the LLVM garbage collectors. For more details,
5676see <a href="GarbageCollection.html">Accurate Garbage Collection with
5677LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5678
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5679<p>The garbage collection intrinsics only operate on objects in the generic
5680 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5681
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5682</div>
5683
5684<!-- _______________________________________________________________________ -->
5685<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5686 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5687</div>
5688
5689<div class="doc_text">
5690
5691<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5692<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5693 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5694</pre>
5695
5696<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5697<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]5698 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5699
5700<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5701<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5702 root pointer. The second pointer (which must be either a constant or a
5703 global value address) contains the meta-data to be associated with the
5704 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5705
5706<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5707<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]5708 location. At compile-time, the code generator generates information to allow
5709 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5710 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5711 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5712
5713</div>
5714
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5715<!-- _______________________________________________________________________ -->
5716<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5717 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5718</div>
5719
5720<div class="doc_text">
5721
5722<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5723<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5724 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5725</pre>
5726
5727<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5728<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5729 locations, allowing garbage collector implementations that require read
5730 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5731
5732<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5733<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]5734 allocated from the garbage collector. The first object is a pointer to the
5735 start of the referenced object, if needed by the language runtime (otherwise
5736 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5737
5738<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5739<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5740 instruction, but may be replaced with substantially more complex code by the
5741 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5742 may only be used in a function which <a href="#gc">specifies a GC
5743 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5744
5745</div>
5746
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5747<!-- _______________________________________________________________________ -->
5748<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5749 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5750</div>
5751
5752<div class="doc_text">
5753
5754<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5755<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5756 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5757</pre>
5758
5759<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5760<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5761 locations, allowing garbage collector implementations that require write
5762 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5763
5764<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5765<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]5766 object to store it to, and the third is the address of the field of Obj to
5767 store to. If the runtime does not require a pointer to the object, Obj may
5768 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5769
5770<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5771<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5772 instruction, but may be replaced with substantially more complex code by the
5773 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5774 may only be used in a function which <a href="#gc">specifies a GC
5775 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5776
5777</div>
5778
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5779<!-- ======================================================================= -->
5780<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5781 <a name="int_codegen">Code Generator Intrinsics</a>
5782</div>
5783
5784<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5785
5786<p>These intrinsics are provided by LLVM to expose special features that may
5787 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5788
5789</div>
5790
5791<!-- _______________________________________________________________________ -->
5792<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5793 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5794</div>
5795
5796<div class="doc_text">
5797
5798<h5>Syntax:</h5>
5799<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5800 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5801</pre>
5802
5803<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5804<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5805 target-specific value indicating the return address of the current function
5806 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5807
5808<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5809<p>The argument to this intrinsic indicates which function to return the address
5810 for. Zero indicates the calling function, one indicates its caller, etc.
5811 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5812
5813<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5814<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5815 indicating the return address of the specified call frame, or zero if it
5816 cannot be identified. The value returned by this intrinsic is likely to be
5817 incorrect or 0 for arguments other than zero, so it should only be used for
5818 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5819
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5820<p>Note that calling this intrinsic does not prevent function inlining or other
5821 aggressive transformations, so the value returned may not be that of the
5822 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5823
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5824</div>
5825
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5826<!-- _______________________________________________________________________ -->
5827<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5828 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5829</div>
5830
5831<div class="doc_text">
5832
5833<h5>Syntax:</h5>
5834<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5835 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5836</pre>
5837
5838<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5839<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5840 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5841
5842<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5843<p>The argument to this intrinsic indicates which function to return the frame
5844 pointer for. Zero indicates the calling function, one indicates its caller,
5845 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5846
5847<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5848<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5849 indicating the frame address of the specified call frame, or zero if it
5850 cannot be identified. The value returned by this intrinsic is likely to be
5851 incorrect or 0 for arguments other than zero, so it should only be used for
5852 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5853
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5854<p>Note that calling this intrinsic does not prevent function inlining or other
5855 aggressive transformations, so the value returned may not be that of the
5856 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5857
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5858</div>
5859
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5860<!-- _______________________________________________________________________ -->
5861<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5862 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5863</div>
5864
5865<div class="doc_text">
5866
5867<h5>Syntax:</h5>
5868<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5869 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5870</pre>
5871
5872<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5873<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5874 of the function stack, for use
5875 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5876 useful for implementing language features like scoped automatic variable
5877 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5878
5879<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5880<p>This intrinsic returns a opaque pointer value that can be passed
5881 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5882 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5883 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5884 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5885 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5886 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5887
5888</div>
5889
5890<!-- _______________________________________________________________________ -->
5891<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5892 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5893</div>
5894
5895<div class="doc_text">
5896
5897<h5>Syntax:</h5>
5898<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5899 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5900</pre>
5901
5902<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5903<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5904 the function stack to the state it was in when the
5905 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5906 executed. This is useful for implementing language features like scoped
5907 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5908
5909<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5910<p>See the description
5911 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5912
5913</div>
5914
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5915<!-- _______________________________________________________________________ -->
5916<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5917 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5918</div>
5919
5920<div class="doc_text">
5921
5922<h5>Syntax:</h5>
5923<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5924 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]5925</pre>
5926
5927<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5928<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5929 insert a prefetch instruction if supported; otherwise, it is a noop.
5930 Prefetches have no effect on the behavior of the program but can change its
5931 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5932
5933<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5934<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5935 specifier determining if the fetch should be for a read (0) or write (1),
5936 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5937 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5938 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5939
5940<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5941<p>This intrinsic does not modify the behavior of the program. In particular,
5942 prefetches cannot trap and do not produce a value. On targets that support
5943 this intrinsic, the prefetch can provide hints to the processor cache for
5944 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5945
5946</div>
5947
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5948<!-- _______________________________________________________________________ -->
5949<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5950 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5951</div>
5952
5953<div class="doc_text">
5954
5955<h5>Syntax:</h5>
5956<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5957 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5958</pre>
5959
5960<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5961<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5962 Counter (PC) in a region of code to simulators and other tools. The method
5963 is target specific, but it is expected that the marker will use exported
5964 symbols to transmit the PC of the marker. The marker makes no guarantees
5965 that it will remain with any specific instruction after optimizations. It is
5966 possible that the presence of a marker will inhibit optimizations. The
5967 intended use is to be inserted after optimizations to allow correlations of
5968 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5969
5970<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5971<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5972
5973<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5974<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5975 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5976
5977</div>
5978
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5979<!-- _______________________________________________________________________ -->
5980<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5981 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5982</div>
5983
5984<div class="doc_text">
5985
5986<h5>Syntax:</h5>
5987<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5988 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5989</pre>
5990
5991<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5992<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5993 counter register (or similar low latency, high accuracy clocks) on those
5994 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5995 should map to RPCC. As the backing counters overflow quickly (on the order
5996 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5997
5998<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5999<p>When directly supported, reading the cycle counter should not modify any
6000 memory. Implementations are allowed to either return a application specific
6001 value or a system wide value. On backends without support, this is lowered
6002 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6003
6004</div>
6005
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6006<!-- ======================================================================= -->
6007<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6008 <a name="int_libc">Standard C Library Intrinsics</a>
6009</div>
6010
6011<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6012
6013<p>LLVM provides intrinsics for a few important standard C library functions.
6014 These intrinsics allow source-language front-ends to pass information about
6015 the alignment of the pointer arguments to the code generator, providing
6016 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6017
6018</div>
6019
6020<!-- _______________________________________________________________________ -->
6021<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6022 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6023</div>
6024
6025<div class="doc_text">
6026
6027<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6028<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]6029 integer bit width and for different address spaces. Not all targets support
6030 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6031
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6032<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6033 declare void @llvm.memcpy.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6034 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6035 declare void @llvm.memcpy.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6036 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6037</pre>
6038
6039<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6040<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6041 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6042
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6043<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6044 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6045 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6046
6047<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6048
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6049<p>The first argument is a pointer to the destination, the second is a pointer
6050 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6051 number of bytes to copy, the fourth argument is the alignment of the
6052 source and destination locations, and the fifth is a boolean indicating a
6053 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6054
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6055<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]6056 then the caller guarantees that both the source and destination pointers are
6057 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6058
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6059<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6060 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6061 The detailed access behavior is not very cleanly specified and it is unwise
6062 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6063
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6064<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6065
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6066<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6067 source location to the destination location, which are not allowed to
6068 overlap. It copies "len" bytes of memory over. If the argument is known to
6069 be aligned to some boundary, this can be specified as the fourth argument,
6070 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6071
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6072</div>
6073
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6074<!-- _______________________________________________________________________ -->
6075<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6076 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6077</div>
6078
6079<div class="doc_text">
6080
6081<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6082<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]6083 width and for different address space. Not all targets support all bit
6084 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6085
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6086<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6087 declare void @llvm.memmove.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6088 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6089 declare void @llvm.memmove.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6090 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6091</pre>
6092
6093<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6094<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6095 source location to the destination location. It is similar to the
6096 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6097 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6098
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6099<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6100 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6101 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6102
6103<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6104
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6105<p>The first argument is a pointer to the destination, the second is a pointer
6106 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6107 number of bytes to copy, the fourth argument is the alignment of the
6108 source and destination locations, and the fifth is a boolean indicating a
6109 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6110
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6111<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]6112 then the caller guarantees that the source and destination pointers are
6113 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6114
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6115<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6116 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6117 The detailed access behavior is not very cleanly specified and it is unwise
6118 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6119
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6120<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6121
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6122<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6123 source location to the destination location, which may overlap. It copies
6124 "len" bytes of memory over. If the argument is known to be aligned to some
6125 boundary, this can be specified as the fourth argument, otherwise it should
6126 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6127
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6128</div>
6129
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6130<!-- _______________________________________________________________________ -->
6131<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6132 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6133</div>
6134
6135<div class="doc_text">
6136
6137<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6138<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]6139 width and for different address spaces. Not all targets support all bit
6140 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6141
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6142<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6143 declare void @llvm.memset.p0i8.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6144 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6145 declare void @llvm.memset.p0i8.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6146 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6147</pre>
6148
6149<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6150<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6151 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6152
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6153<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6154 intrinsic does not return a value, takes extra alignment/volatile arguments,
6155 and the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6156
6157<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6158<p>The first argument is a pointer to the destination to fill, the second is the
6159 byte value to fill it with, the third argument is an integer argument
6160 specifying the number of bytes to fill, and the fourth argument is the known
6161 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6162
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6163<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]6164 then the caller guarantees that the destination pointer is aligned to that
6165 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6166
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6167<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6168 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6169 The detailed access behavior is not very cleanly specified and it is unwise
6170 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6171
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6172<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6173<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6174 at the destination location. If the argument is known to be aligned to some
6175 boundary, this can be specified as the fourth argument, otherwise it should
6176 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6177
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6178</div>
6179
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6180<!-- _______________________________________________________________________ -->
6181<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6182 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6183</div>
6184
6185<div class="doc_text">
6186
6187<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6188<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6189 floating point or vector of floating point type. Not all targets support all
6190 types however.</p>
6191
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6192<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6193 declare float @llvm.sqrt.f32(float %Val)
6194 declare double @llvm.sqrt.f64(double %Val)
6195 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6196 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6197 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6198</pre>
6199
6200<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6201<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6202 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6203 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6204 behavior for negative numbers other than -0.0 (which allows for better
6205 optimization, because there is no need to worry about errno being
6206 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]6207
6208<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6209<p>The argument and return value are floating point numbers of the same
6210 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6211
6212<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6213<p>This function returns the sqrt of the specified operand if it is a
6214 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6215
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6216</div>
6217
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6218<!-- _______________________________________________________________________ -->
6219<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6220 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6221</div>
6222
6223<div class="doc_text">
6224
6225<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6226<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6227 floating point or vector of floating point type. Not all targets support all
6228 types however.</p>
6229
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6230<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6231 declare float @llvm.powi.f32(float %Val, i32 %power)
6232 declare double @llvm.powi.f64(double %Val, i32 %power)
6233 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6234 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6235 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6236</pre>
6237
6238<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6239<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6240 specified (positive or negative) power. The order of evaluation of
6241 multiplications is not defined. When a vector of floating point type is
6242 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6243
6244<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6245<p>The second argument is an integer power, and the first is a value to raise to
6246 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6247
6248<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6249<p>This function returns the first value raised to the second power with an
6250 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6251
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6252</div>
6253
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6254<!-- _______________________________________________________________________ -->
6255<div class="doc_subsubsection">
6256 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6257</div>
6258
6259<div class="doc_text">
6260
6261<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6262<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6263 floating point or vector of floating point type. Not all targets support all
6264 types however.</p>
6265
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6266<pre>
6267 declare float @llvm.sin.f32(float %Val)
6268 declare double @llvm.sin.f64(double %Val)
6269 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6270 declare fp128 @llvm.sin.f128(fp128 %Val)
6271 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6272</pre>
6273
6274<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6275<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6276
6277<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6278<p>The argument and return value are floating point numbers of the same
6279 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6280
6281<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6282<p>This function returns the sine of the specified operand, returning the same
6283 values as the libm <tt>sin</tt> functions would, and handles error conditions
6284 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6285
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6286</div>
6287
6288<!-- _______________________________________________________________________ -->
6289<div class="doc_subsubsection">
6290 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6291</div>
6292
6293<div class="doc_text">
6294
6295<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6296<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6297 floating point or vector of floating point type. Not all targets support all
6298 types however.</p>
6299
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6300<pre>
6301 declare float @llvm.cos.f32(float %Val)
6302 declare double @llvm.cos.f64(double %Val)
6303 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6304 declare fp128 @llvm.cos.f128(fp128 %Val)
6305 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6306</pre>
6307
6308<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6309<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6310
6311<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6312<p>The argument and return value are floating point numbers of the same
6313 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6314
6315<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6316<p>This function returns the cosine of the specified operand, returning the same
6317 values as the libm <tt>cos</tt> functions would, and handles error conditions
6318 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6319
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6320</div>
6321
6322<!-- _______________________________________________________________________ -->
6323<div class="doc_subsubsection">
6324 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6325</div>
6326
6327<div class="doc_text">
6328
6329<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6330<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6331 floating point or vector of floating point type. Not all targets support all
6332 types however.</p>
6333
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6334<pre>
6335 declare float @llvm.pow.f32(float %Val, float %Power)
6336 declare double @llvm.pow.f64(double %Val, double %Power)
6337 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6338 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6339 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6340</pre>
6341
6342<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6343<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6344 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6345
6346<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6347<p>The second argument is a floating point power, and the first is a value to
6348 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6349
6350<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6351<p>This function returns the first value raised to the second power, returning
6352 the same values as the libm <tt>pow</tt> functions would, and handles error
6353 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6354
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6355</div>
6356
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6357<!-- ======================================================================= -->
6358<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6359 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6360</div>
6361
6362<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6363
6364<p>LLVM provides intrinsics for a few important bit manipulation operations.
6365 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6366
6367</div>
6368
6369<!-- _______________________________________________________________________ -->
6370<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6371 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6372</div>
6373
6374<div class="doc_text">
6375
6376<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6377<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6378 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6379
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6380<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6381 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6382 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6383 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6384</pre>
6385
6386<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6387<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6388 values with an even number of bytes (positive multiple of 16 bits). These
6389 are useful for performing operations on data that is not in the target's
6390 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6391
6392<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6393<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6394 and low byte of the input i16 swapped. Similarly,
6395 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6396 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6397 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6398 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6399 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6400 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6401
6402</div>
6403
6404<!-- _______________________________________________________________________ -->
6405<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6406 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6407</div>
6408
6409<div class="doc_text">
6410
6411<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6412<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]6413 width. Not all targets support all bit widths however.</p>
6414
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6415<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6416 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6417 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6418 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6419 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6420 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6421</pre>
6422
6423<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6424<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6425 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6426
6427<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6428<p>The only argument is the value to be counted. The argument may be of any
6429 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6430
6431<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6432<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]6433
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6434</div>
6435
6436<!-- _______________________________________________________________________ -->
6437<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6438 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6439</div>
6440
6441<div class="doc_text">
6442
6443<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6444<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6445 integer bit width. Not all targets support all bit widths however.</p>
6446
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6447<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6448 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6449 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6450 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6451 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6452 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6453</pre>
6454
6455<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6456<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6457 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6458
6459<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6460<p>The only argument is the value to be counted. The argument may be of any
6461 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6462
6463<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6464<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6465 zeros in a variable. If the src == 0 then the result is the size in bits of
6466 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6467
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6468</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6469
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6470<!-- _______________________________________________________________________ -->
6471<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6472 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6473</div>
6474
6475<div class="doc_text">
6476
6477<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6478<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6479 integer bit width. Not all targets support all bit widths however.</p>
6480
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6481<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6482 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6483 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6484 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6485 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6486 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6487</pre>
6488
6489<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6490<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6491 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6492
6493<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6494<p>The only argument is the value to be counted. The argument may be of any
6495 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6496
6497<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6498<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6499 zeros in a variable. If the src == 0 then the result is the size in bits of
6500 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6501
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6502</div>
6503
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6504<!-- ======================================================================= -->
6505<div class="doc_subsection">
6506 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6507</div>
6508
6509<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6510
6511<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6512
6513</div>
6514
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6515<!-- _______________________________________________________________________ -->
6516<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6517 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6518</div>
6519
6520<div class="doc_text">
6521
6522<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6523<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]6524 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6525
6526<pre>
6527 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6528 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6529 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6530</pre>
6531
6532<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6533<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6534 a signed addition of the two arguments, and indicate whether an overflow
6535 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6536
6537<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6538<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]6539 be of integer types of any bit width, but they must have the same bit
6540 width. The second element of the result structure must be of
6541 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6542 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6543
6544<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6545<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6546 a signed addition of the two variables. They return a structure &mdash; the
6547 first element of which is the signed summation, and the second element of
6548 which is a bit specifying if the signed summation resulted in an
6549 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6550
6551<h5>Examples:</h5>
6552<pre>
6553 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6554 %sum = extractvalue {i32, i1} %res, 0
6555 %obit = extractvalue {i32, i1} %res, 1
6556 br i1 %obit, label %overflow, label %normal
6557</pre>
6558
6559</div>
6560
6561<!-- _______________________________________________________________________ -->
6562<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6563 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6564</div>
6565
6566<div class="doc_text">
6567
6568<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6569<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]6570 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6571
6572<pre>
6573 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6574 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6575 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6576</pre>
6577
6578<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6579<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6580 an unsigned addition of the two arguments, and indicate whether a carry
6581 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6582
6583<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6584<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]6585 be of integer types of any bit width, but they must have the same bit
6586 width. The second element of the result structure must be of
6587 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6588 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6589
6590<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6591<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6592 an unsigned addition of the two arguments. They return a structure &mdash;
6593 the first element of which is the sum, and the second element of which is a
6594 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6595
6596<h5>Examples:</h5>
6597<pre>
6598 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6599 %sum = extractvalue {i32, i1} %res, 0
6600 %obit = extractvalue {i32, i1} %res, 1
6601 br i1 %obit, label %carry, label %normal
6602</pre>
6603
6604</div>
6605
6606<!-- _______________________________________________________________________ -->
6607<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6608 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6609</div>
6610
6611<div class="doc_text">
6612
6613<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6614<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]6615 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6616
6617<pre>
6618 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6619 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6620 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6621</pre>
6622
6623<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6624<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6625 a signed subtraction of the two arguments, and indicate whether an overflow
6626 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6627
6628<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6629<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]6630 be of integer types of any bit width, but they must have the same bit
6631 width. The second element of the result structure must be of
6632 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6633 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6634
6635<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6636<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6637 a signed subtraction of the two arguments. They return a structure &mdash;
6638 the first element of which is the subtraction, and the second element of
6639 which is a bit specifying if the signed subtraction resulted in an
6640 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6641
6642<h5>Examples:</h5>
6643<pre>
6644 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6645 %sum = extractvalue {i32, i1} %res, 0
6646 %obit = extractvalue {i32, i1} %res, 1
6647 br i1 %obit, label %overflow, label %normal
6648</pre>
6649
6650</div>
6651
6652<!-- _______________________________________________________________________ -->
6653<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6654 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6655</div>
6656
6657<div class="doc_text">
6658
6659<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6660<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]6661 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6662
6663<pre>
6664 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6665 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6666 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6667</pre>
6668
6669<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6670<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6671 an unsigned subtraction of the two arguments, and indicate whether an
6672 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6673
6674<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6675<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]6676 be of integer types of any bit width, but they must have the same bit
6677 width. The second element of the result structure must be of
6678 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6679 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6680
6681<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6682<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6683 an unsigned subtraction of the two arguments. They return a structure &mdash;
6684 the first element of which is the subtraction, and the second element of
6685 which is a bit specifying if the unsigned subtraction resulted in an
6686 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6687
6688<h5>Examples:</h5>
6689<pre>
6690 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6691 %sum = extractvalue {i32, i1} %res, 0
6692 %obit = extractvalue {i32, i1} %res, 1
6693 br i1 %obit, label %overflow, label %normal
6694</pre>
6695
6696</div>
6697
6698<!-- _______________________________________________________________________ -->
6699<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6700 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6701</div>
6702
6703<div class="doc_text">
6704
6705<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6706<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]6707 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6708
6709<pre>
6710 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6711 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6712 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6713</pre>
6714
6715<h5>Overview:</h5>
6716
6717<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6718 a signed multiplication of the two arguments, and indicate whether an
6719 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6720
6721<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6722<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]6723 be of integer types of any bit width, but they must have the same bit
6724 width. The second element of the result structure must be of
6725 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6726 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6727
6728<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6729<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6730 a signed multiplication of the two arguments. They return a structure &mdash;
6731 the first element of which is the multiplication, and the second element of
6732 which is a bit specifying if the signed multiplication resulted in an
6733 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6734
6735<h5>Examples:</h5>
6736<pre>
6737 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6738 %sum = extractvalue {i32, i1} %res, 0
6739 %obit = extractvalue {i32, i1} %res, 1
6740 br i1 %obit, label %overflow, label %normal
6741</pre>
6742
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6743</div>
6744
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6745<!-- _______________________________________________________________________ -->
6746<div class="doc_subsubsection">
6747 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6748</div>
6749
6750<div class="doc_text">
6751
6752<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6753<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]6754 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6755
6756<pre>
6757 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6758 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6759 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6760</pre>
6761
6762<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6763<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6764 a unsigned multiplication of the two arguments, and indicate whether an
6765 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6766
6767<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6768<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]6769 be of integer types of any bit width, but they must have the same bit
6770 width. The second element of the result structure must be of
6771 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6772 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6773
6774<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6775<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6776 an unsigned multiplication of the two arguments. They return a structure
6777 &mdash; the first element of which is the multiplication, and the second
6778 element of which is a bit specifying if the unsigned multiplication resulted
6779 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6780
6781<h5>Examples:</h5>
6782<pre>
6783 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6784 %sum = extractvalue {i32, i1} %res, 0
6785 %obit = extractvalue {i32, i1} %res, 1
6786 br i1 %obit, label %overflow, label %normal
6787</pre>
6788
6789</div>
6790
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6791<!-- ======================================================================= -->
6792<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6793 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6794</div>
6795
6796<div class="doc_text">
6797
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6798<p>Half precision floating point is a storage-only format. This means that it is
6799 a dense encoding (in memory) but does not support computation in the
6800 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6801
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6802<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6803 value as an i16, then convert it to float with <a
6804 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6805 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6806 double etc). To store the value back to memory, it is first converted to
6807 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6808 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6809 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6810</div>
6811
6812<!-- _______________________________________________________________________ -->
6813<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6814 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6815</div>
6816
6817<div class="doc_text">
6818
6819<h5>Syntax:</h5>
6820<pre>
6821 declare i16 @llvm.convert.to.fp16(f32 %a)
6822</pre>
6823
6824<h5>Overview:</h5>
6825<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6826 a conversion from single precision floating point format to half precision
6827 floating point format.</p>
6828
6829<h5>Arguments:</h5>
6830<p>The intrinsic function contains single argument - the value to be
6831 converted.</p>
6832
6833<h5>Semantics:</h5>
6834<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6835 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6836 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6837 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6838
6839<h5>Examples:</h5>
6840<pre>
6841 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6842 store i16 %res, i16* @x, align 2
6843</pre>
6844
6845</div>
6846
6847<!-- _______________________________________________________________________ -->
6848<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6849 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6850</div>
6851
6852<div class="doc_text">
6853
6854<h5>Syntax:</h5>
6855<pre>
6856 declare f32 @llvm.convert.from.fp16(i16 %a)
6857</pre>
6858
6859<h5>Overview:</h5>
6860<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6861 a conversion from half precision floating point format to single precision
6862 floating point format.</p>
6863
6864<h5>Arguments:</h5>
6865<p>The intrinsic function contains single argument - the value to be
6866 converted.</p>
6867
6868<h5>Semantics:</h5>
6869<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6870 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6871 precision floating point format. The input half-float value is represented by
6872 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6873
6874<h5>Examples:</h5>
6875<pre>
6876 %a = load i16* @x, align 2
6877 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6878</pre>
6879
6880</div>
6881
6882<!-- ======================================================================= -->
6883<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6884 <a name="int_debugger">Debugger Intrinsics</a>
6885</div>
6886
6887<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6888
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6889<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6890 prefix), are described in
6891 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6892 Level Debugging</a> document.</p>
6893
6894</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6895
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6896<!-- ======================================================================= -->
6897<div class="doc_subsection">
6898 <a name="int_eh">Exception Handling Intrinsics</a>
6899</div>
6900
6901<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6902
6903<p>The LLVM exception handling intrinsics (which all start with
6904 <tt>llvm.eh.</tt> prefix), are described in
6905 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6906 Handling</a> document.</p>
6907
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6908</div>
6909
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6910<!-- ======================================================================= -->
6911<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6912 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6913</div>
6914
6915<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6916
6917<p>This intrinsic makes it possible to excise one parameter, marked with
6918 the <tt>nest</tt> attribute, from a function. The result is a callable
6919 function pointer lacking the nest parameter - the caller does not need to
6920 provide a value for it. Instead, the value to use is stored in advance in a
6921 "trampoline", a block of memory usually allocated on the stack, which also
6922 contains code to splice the nest value into the argument list. This is used
6923 to implement the GCC nested function address extension.</p>
6924
6925<p>For example, if the function is
6926 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6927 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6928 follows:</p>
6929
6930<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6931<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6932 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6933 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6934 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6935 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6936</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6937</div>
6938
6939<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6940 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6941
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6942</div>
6943
6944<!-- _______________________________________________________________________ -->
6945<div class="doc_subsubsection">
6946 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6947</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6948
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6949<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6950
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6951<h5>Syntax:</h5>
6952<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6953 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]6954</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6955
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6956<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6957<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6958 function pointer suitable for executing it.</p>
6959
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6960<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6961<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6962 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6963 sufficiently aligned block of memory; this memory is written to by the
6964 intrinsic. Note that the size and the alignment are target-specific - LLVM
6965 currently provides no portable way of determining them, so a front-end that
6966 generates this intrinsic needs to have some target-specific knowledge.
6967 The <tt>func</tt> argument must hold a function bitcast to
6968 an <tt>i8*</tt>.</p>
6969
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6970<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6971<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6972 dependent code, turning it into a function. A pointer to this function is
6973 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6974 function pointer type</a> before being called. The new function's signature
6975 is the same as that of <tt>func</tt> with any arguments marked with
6976 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6977 is allowed, and it must be of pointer type. Calling the new function is
6978 equivalent to calling <tt>func</tt> with the same argument list, but
6979 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6980 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6981 by <tt>tramp</tt> is modified, then the effect of any later call to the
6982 returned function pointer is undefined.</p>
6983
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6984</div>
6985
6986<!-- ======================================================================= -->
6987<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6988 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6989</div>
6990
6991<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6992
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6993<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6994 hardware constructs for atomic operations and memory synchronization. This
6995 provides an interface to the hardware, not an interface to the programmer. It
6996 is aimed at a low enough level to allow any programming models or APIs
6997 (Application Programming Interfaces) which need atomic behaviors to map
6998 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6999 hardware provides a "universal IR" for source languages, it also provides a
7000 starting point for developing a "universal" atomic operation and
7001 synchronization IR.</p>
7002
7003<p>These do <em>not</em> form an API such as high-level threading libraries,
7004 software transaction memory systems, atomic primitives, and intrinsic
7005 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7006 application libraries. The hardware interface provided by LLVM should allow
7007 a clean implementation of all of these APIs and parallel programming models.
7008 No one model or paradigm should be selected above others unless the hardware
7009 itself ubiquitously does so.</p>
7010
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7011</div>
7012
7013<!-- _______________________________________________________________________ -->
7014<div class="doc_subsubsection">
7015 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7016</div>
7017<div class="doc_text">
7018<h5>Syntax:</h5>
7019<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7020 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]7021</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7022
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7023<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7024<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7025 specific pairs of memory access types.</p>
7026
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7027<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7028<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7029 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7030 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7031 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7032
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7033<ul>
7034 <li><tt>ll</tt>: load-load barrier</li>
7035 <li><tt>ls</tt>: load-store barrier</li>
7036 <li><tt>sl</tt>: store-load barrier</li>
7037 <li><tt>ss</tt>: store-store barrier</li>
7038 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7039</ul>
7040
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7041<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7042<p>This intrinsic causes the system to enforce some ordering constraints upon
7043 the loads and stores of the program. This barrier does not
7044 indicate <em>when</em> any events will occur, it only enforces
7045 an <em>order</em> in which they occur. For any of the specified pairs of load
7046 and store operations (f.ex. load-load, or store-load), all of the first
7047 operations preceding the barrier will complete before any of the second
7048 operations succeeding the barrier begin. Specifically the semantics for each
7049 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7050
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7051<ul>
7052 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7053 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7054 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7055 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7056 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7057 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7058 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7059 load after the barrier begins.</li>
7060</ul>
7061
7062<p>These semantics are applied with a logical "and" behavior when more than one
7063 is enabled in a single memory barrier intrinsic.</p>
7064
7065<p>Backends may implement stronger barriers than those requested when they do
7066 not support as fine grained a barrier as requested. Some architectures do
7067 not need all types of barriers and on such architectures, these become
7068 noops.</p>
7069
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7070<h5>Example:</h5>
7071<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7072%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7073%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7074 store i32 4, %ptr
7075
7076%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
7077 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
7078 <i>; guarantee the above finishes</i>
7079 store i32 8, %ptr <i>; before this begins</i>
7080</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7081
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7082</div>
7083
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7084<!-- _______________________________________________________________________ -->
7085<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7086 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7087</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7088
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7089<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7090
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7091<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7092<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7093 any integer bit width and for different address spaces. Not all targets
7094 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7095
7096<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7097 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
7098 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
7099 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
7100 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]7101</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7102
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7103<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7104<p>This loads a value in memory and compares it to a given value. If they are
7105 equal, it stores a new value into the memory.</p>
7106
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7107<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7108<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7109 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7110 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7111 this integer type. While any bit width integer may be used, targets may only
7112 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7113
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7114<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7115<p>This entire intrinsic must be executed atomically. It first loads the value
7116 in memory pointed to by <tt>ptr</tt> and compares it with the
7117 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7118 memory. The loaded value is yielded in all cases. This provides the
7119 equivalent of an atomic compare-and-swap operation within the SSA
7120 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7121
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7122<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7123<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7124%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7125%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7126 store i32 4, %ptr
7127
7128%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7129%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7130 <i>; yields {i32}:result1 = 4</i>
7131%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7132%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7133
7134%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7135%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7136 <i>; yields {i32}:result2 = 8</i>
7137%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7138
7139%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7140</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7141
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7142</div>
7143
7144<!-- _______________________________________________________________________ -->
7145<div class="doc_subsubsection">
7146 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7147</div>
7148<div class="doc_text">
7149<h5>Syntax:</h5>
7150
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7151<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7152 integer bit width. Not all targets support all bit widths however.</p>
7153
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7154<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7155 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
7156 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
7157 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
7158 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]7159</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7160
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7161<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7162<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7163 the value from memory. It then stores the value in <tt>val</tt> in the memory
7164 at <tt>ptr</tt>.</p>
7165
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7166<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7167<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7168 the <tt>val</tt> argument and the result must be integers of the same bit
7169 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7170 integer type. The targets may only lower integer representations they
7171 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7172
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7173<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7174<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7175 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7176 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7177
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7178<h5>Examples:</h5>
7179<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7180%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7181%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7182 store i32 4, %ptr
7183
7184%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7185%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7186 <i>; yields {i32}:result1 = 4</i>
7187%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7188%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7189
7190%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7191%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7192 <i>; yields {i32}:result2 = 8</i>
7193
7194%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7195%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7196</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7197
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7198</div>
7199
7200<!-- _______________________________________________________________________ -->
7201<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7202 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7203
7204</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7205
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7206<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7207
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7208<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7209<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7210 any integer bit width. Not all targets support all bit widths however.</p>
7211
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7212<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7213 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7214 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7215 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7216 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]7217</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7218
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7219<h5>Overview:</h5>
7220<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7221 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7222
7223<h5>Arguments:</h5>
7224<p>The intrinsic takes two arguments, the first a pointer to an integer value
7225 and the second an integer value. The result is also an integer value. These
7226 integer types can have any bit width, but they must all have the same bit
7227 width. The targets may only lower integer representations they support.</p>
7228
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7229<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7230<p>This intrinsic does a series of operations atomically. It first loads the
7231 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7232 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]7233
7234<h5>Examples:</h5>
7235<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7236%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7237%ptr = bitcast i8* %mallocP to i32*
7238 store i32 4, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7239%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7240 <i>; yields {i32}:result1 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7241%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7242 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7243%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7244 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7245%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7246</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7247
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7248</div>
7249
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7250<!-- _______________________________________________________________________ -->
7251<div class="doc_subsubsection">
7252 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7253
7254</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7255
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7256<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7257
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7258<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7259<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7260 any integer bit width and for different address spaces. Not all targets
7261 support all bit widths however.</p>
7262
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7263<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7264 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7265 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7266 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7267 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]7268</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7269
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7270<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7271<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7272 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7273
7274<h5>Arguments:</h5>
7275<p>The intrinsic takes two arguments, the first a pointer to an integer value
7276 and the second an integer value. The result is also an integer value. These
7277 integer types can have any bit width, but they must all have the same bit
7278 width. The targets may only lower integer representations they support.</p>
7279
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7280<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7281<p>This intrinsic does a series of operations atomically. It first loads the
7282 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7283 result to <tt>ptr</tt>. It yields the original value stored
7284 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7285
7286<h5>Examples:</h5>
7287<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7288%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7289%ptr = bitcast i8* %mallocP to i32*
7290 store i32 8, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7291%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7292 <i>; yields {i32}:result1 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7293%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7294 <i>; yields {i32}:result2 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7295%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7296 <i>; yields {i32}:result3 = 2</i>
7297%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7298</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7299
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7300</div>
7301
7302<!-- _______________________________________________________________________ -->
7303<div class="doc_subsubsection">
7304 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7305 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7306 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7307 <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]7308</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7309
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7310<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7311
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7312<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7313<p>These are overloaded intrinsics. You can
7314 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7315 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7316 bit width and for different address spaces. Not all targets support all bit
7317 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7318
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7319<pre>
7320 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7321 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7322 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7323 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]7324</pre>
7325
7326<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7327 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7328 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7329 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7330 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]7331</pre>
7332
7333<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7334 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7335 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7336 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7337 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]7338</pre>
7339
7340<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7341 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7342 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7343 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7344 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]7345</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7346
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7347<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7348<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7349 the value stored in memory at <tt>ptr</tt>. It yields the original value
7350 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7351
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7352<h5>Arguments:</h5>
7353<p>These intrinsics take two arguments, the first a pointer to an integer value
7354 and the second an integer value. The result is also an integer value. These
7355 integer types can have any bit width, but they must all have the same bit
7356 width. The targets may only lower integer representations they support.</p>
7357
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7358<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7359<p>These intrinsics does a series of operations atomically. They first load the
7360 value stored at <tt>ptr</tt>. They then do the bitwise
7361 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7362 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7363
7364<h5>Examples:</h5>
7365<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7366%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7367%ptr = bitcast i8* %mallocP to i32*
7368 store i32 0x0F0F, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7369%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7370 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7371%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7372 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7373%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7374 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7375%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7376 <i>; yields {i32}:result3 = FF</i>
7377%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7378</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7379
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7380</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7381
7382<!-- _______________________________________________________________________ -->
7383<div class="doc_subsubsection">
7384 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7385 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7386 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7387 <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]7388</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7389
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7390<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7391
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7392<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7393<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7394 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7395 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7396 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7397
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7398<pre>
7399 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7400 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7401 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7402 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]7403</pre>
7404
7405<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7406 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7407 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7408 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7409 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]7410</pre>
7411
7412<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7413 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7414 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7415 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7416 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]7417</pre>
7418
7419<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7420 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7421 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7422 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7423 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]7424</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7425
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7426<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7427<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7428 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7429 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7430
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7431<h5>Arguments:</h5>
7432<p>These intrinsics take two arguments, the first a pointer to an integer value
7433 and the second an integer value. The result is also an integer value. These
7434 integer types can have any bit width, but they must all have the same bit
7435 width. The targets may only lower integer representations they support.</p>
7436
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7437<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7438<p>These intrinsics does a series of operations atomically. They first load the
7439 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7440 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7441 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7442
7443<h5>Examples:</h5>
7444<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7445%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7446%ptr = bitcast i8* %mallocP to i32*
7447 store i32 7, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7448%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7449 <i>; yields {i32}:result0 = 7</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7450%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7451 <i>; yields {i32}:result1 = -2</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7452%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7453 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7454%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7455 <i>; yields {i32}:result3 = 8</i>
7456%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7457</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7458
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7459</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7460
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7461
7462<!-- ======================================================================= -->
7463<div class="doc_subsection">
7464 <a name="int_memorymarkers">Memory Use Markers</a>
7465</div>
7466
7467<div class="doc_text">
7468
7469<p>This class of intrinsics exists to information about the lifetime of memory
7470 objects and ranges where variables are immutable.</p>
7471
7472</div>
7473
7474<!-- _______________________________________________________________________ -->
7475<div class="doc_subsubsection">
7476 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7477</div>
7478
7479<div class="doc_text">
7480
7481<h5>Syntax:</h5>
7482<pre>
7483 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7484</pre>
7485
7486<h5>Overview:</h5>
7487<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7488 object's lifetime.</p>
7489
7490<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7491<p>The first argument is a constant integer representing the size of the
7492 object, or -1 if it is variable sized. The second argument is a pointer to
7493 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7494
7495<h5>Semantics:</h5>
7496<p>This intrinsic indicates that before this point in the code, the value of the
7497 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]7498 never be used and has an undefined value. A load from the pointer that
7499 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7500 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7501
7502</div>
7503
7504<!-- _______________________________________________________________________ -->
7505<div class="doc_subsubsection">
7506 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7507</div>
7508
7509<div class="doc_text">
7510
7511<h5>Syntax:</h5>
7512<pre>
7513 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7514</pre>
7515
7516<h5>Overview:</h5>
7517<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7518 object's lifetime.</p>
7519
7520<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7521<p>The first argument is a constant integer representing the size of the
7522 object, or -1 if it is variable sized. The second argument is a pointer to
7523 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7524
7525<h5>Semantics:</h5>
7526<p>This intrinsic indicates that after this point in the code, the value of the
7527 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7528 never be used and has an undefined value. Any stores into the memory object
7529 following this intrinsic may be removed as dead.
7530
7531</div>
7532
7533<!-- _______________________________________________________________________ -->
7534<div class="doc_subsubsection">
7535 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7536</div>
7537
7538<div class="doc_text">
7539
7540<h5>Syntax:</h5>
7541<pre>
7542 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7543</pre>
7544
7545<h5>Overview:</h5>
7546<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7547 a memory object will not change.</p>
7548
7549<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7550<p>The first argument is a constant integer representing the size of the
7551 object, or -1 if it is variable sized. The second argument is a pointer to
7552 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7553
7554<h5>Semantics:</h5>
7555<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7556 the return value, the referenced memory location is constant and
7557 unchanging.</p>
7558
7559</div>
7560
7561<!-- _______________________________________________________________________ -->
7562<div class="doc_subsubsection">
7563 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7564</div>
7565
7566<div class="doc_text">
7567
7568<h5>Syntax:</h5>
7569<pre>
7570 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7571</pre>
7572
7573<h5>Overview:</h5>
7574<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7575 a memory object are mutable.</p>
7576
7577<h5>Arguments:</h5>
7578<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7579 The second argument is a constant integer representing the size of the
7580 object, or -1 if it is variable sized and the third argument is a pointer
7581 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7582
7583<h5>Semantics:</h5>
7584<p>This intrinsic indicates that the memory is mutable again.</p>
7585
7586</div>
7587
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7588<!-- ======================================================================= -->
7589<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7590 <a name="int_general">General Intrinsics</a>
7591</div>
7592
7593<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7594
7595<p>This class of intrinsics is designed to be generic and has no specific
7596 purpose.</p>
7597
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7598</div>
7599
7600<!-- _______________________________________________________________________ -->
7601<div class="doc_subsubsection">
7602 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7603</div>
7604
7605<div class="doc_text">
7606
7607<h5>Syntax:</h5>
7608<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]7609 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]7610</pre>
7611
7612<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7613<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7614
7615<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7616<p>The first argument is a pointer to a value, the second is a pointer to a
7617 global string, the third is a pointer to a global string which is the source
7618 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7619
7620<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7621<p>This intrinsic allows annotation of local variables with arbitrary strings.
7622 This can be useful for special purpose optimizations that want to look for
7623 these annotations. These have no other defined use, they are ignored by code
7624 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7625
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7626</div>
7627
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7628<!-- _______________________________________________________________________ -->
7629<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7630 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7631</div>
7632
7633<div class="doc_text">
7634
7635<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7636<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7637 any integer bit width.</p>
7638
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7639<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]7640 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7641 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7642 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7643 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7644 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]7645</pre>
7646
7647<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7648<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7649
7650<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7651<p>The first argument is an integer value (result of some expression), the
7652 second is a pointer to a global string, the third is a pointer to a global
7653 string which is the source file name, and the last argument is the line
7654 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7655
7656<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7657<p>This intrinsic allows annotations to be put on arbitrary expressions with
7658 arbitrary strings. This can be useful for special purpose optimizations that
7659 want to look for these annotations. These have no other defined use, they
7660 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7661
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7662</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7663
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7664<!-- _______________________________________________________________________ -->
7665<div class="doc_subsubsection">
7666 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7667</div>
7668
7669<div class="doc_text">
7670
7671<h5>Syntax:</h5>
7672<pre>
7673 declare void @llvm.trap()
7674</pre>
7675
7676<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7677<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7678
7679<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7680<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7681
7682<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7683<p>This intrinsics is lowered to the target dependent trap instruction. If the
7684 target does not have a trap instruction, this intrinsic will be lowered to
7685 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7686
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7687</div>
7688
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7689<!-- _______________________________________________________________________ -->
7690<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7691 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7692</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7693
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7694<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7695
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7696<h5>Syntax:</h5>
7697<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7698 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7699</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7700
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7701<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7702<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7703 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7704 ensure that it is placed on the stack before local variables.</p>
7705
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7706<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7707<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7708 arguments. The first argument is the value loaded from the stack
7709 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7710 that has enough space to hold the value of the guard.</p>
7711
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7712<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7713<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7714 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7715 stack. This is to ensure that if a local variable on the stack is
7716 overwritten, it will destroy the value of the guard. When the function exits,
7717 the guard on the stack is checked against the original guard. If they're
7718 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7719 function.</p>
7720
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7721</div>
7722
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7723<!-- _______________________________________________________________________ -->
7724<div class="doc_subsubsection">
7725 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7726</div>
7727
7728<div class="doc_text">
7729
7730<h5>Syntax:</h5>
7731<pre>
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7732 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7733 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7734</pre>
7735
7736<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7737<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7738 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7739 operation like memcpy will either overflow a buffer that corresponds to
7740 an object, or b) to determine that a runtime check for overflow isn't
7741 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7742 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7743
7744<h5>Arguments:</h5>
7745<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7746 argument is a pointer to or into the <tt>object</tt>. The second argument
7747 is a boolean 0 or 1. This argument determines whether you want the
7748 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7749 1, variables are not allowed.</p>
7750
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7751<h5>Semantics:</h5>
7752<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7753 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7754 (depending on the <tt>type</tt> argument if the size cannot be determined
7755 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7756
7757</div>
7758
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7759<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7760<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7761<address>
7762 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7763 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7764 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7765 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7766
7767 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7768 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7769 Last modified: $Date$
7770</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7771
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7772</body>
7773</html>