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gerrit-public.fairphone.software / toolchain / llvm-project / ac355aaf9e7f15abf11c1a3279786ff4b0252733 / . / 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
Dan Gohmanac355aa2010-05-03 14:51:43 +0000[diff] [blame^]2340 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]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">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2799<pre>
2800%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2801@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2802</pre>
2803<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
2804</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2805
2806</div>
2807
2808<!-- ======================================================================= -->
2809<div class="doc_subsection">
2810<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2811</div>
2812
2813<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2814<pre>
2815%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2816@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2817</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2818
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2819<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
2820</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2821
2822</div>
2823
2824
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2825<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2826<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2827<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2828
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2829<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2830
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2831<p>The LLVM instruction set consists of several different classifications of
2832 instructions: <a href="#terminators">terminator
2833 instructions</a>, <a href="#binaryops">binary instructions</a>,
2834 <a href="#bitwiseops">bitwise binary instructions</a>,
2835 <a href="#memoryops">memory instructions</a>, and
2836 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2837
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2838</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2839
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2840<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2841<div class="doc_subsection"> <a name="terminators">Terminator
2842Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2843
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2844<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2845
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2846<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2847 in a program ends with a "Terminator" instruction, which indicates which
2848 block should be executed after the current block is finished. These
2849 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2850 control flow, not values (the one exception being the
2851 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2852
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2853<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2854 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2855 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2856 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2857 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2858 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2859 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2860 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2861
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2862</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2863
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2864<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2865<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2866Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2867
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2868<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2869
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2870<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2871<pre>
2872 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]2873 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2874</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2875
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2876<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2877<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2878 a value) from a function back to the caller.</p>
2879
2880<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2881 value and then causes control flow, and one that just causes control flow to
2882 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2883
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2884<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2885<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2886 return value. The type of the return value must be a
2887 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2888
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2889<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2890 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2891 value or a return value with a type that does not match its type, or if it
2892 has a void return type and contains a '<tt>ret</tt>' instruction with a
2893 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2894
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2895<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2896<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2897 the calling function's context. If the caller is a
2898 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2899 instruction after the call. If the caller was an
2900 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2901 the beginning of the "normal" destination block. If the instruction returns
2902 a value, that value shall set the call or invoke instruction's return
2903 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2904
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2905<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2906<pre>
2907 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2908 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2909 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]2910</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2911
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2912</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2913<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2914<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2915
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2916<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2917
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2918<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2919<pre>
2920 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]2921</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2922
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2923<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2924<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2925 different basic block in the current function. There are two forms of this
2926 instruction, corresponding to a conditional branch and an unconditional
2927 branch.</p>
2928
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2929<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2930<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2931 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2932 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2933 target.</p>
2934
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2935<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2936<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2937 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2938 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2939 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2940
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2941<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2942<pre>
2943Test:
2944 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2945 br i1 %cond, label %IfEqual, label %IfUnequal
2946IfEqual:
2947 <a href="#i_ret">ret</a> i32 1
2948IfUnequal:
2949 <a href="#i_ret">ret</a> i32 0
2950</pre>
2951
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2952</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2953
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2954<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2955<div class="doc_subsubsection">
2956 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2957</div>
2958
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2959<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2960
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2961<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2962<pre>
2963 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2964</pre>
2965
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2966<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2967<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]2968 several different places. It is a generalization of the '<tt>br</tt>'
2969 instruction, allowing a branch to occur to one of many possible
2970 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2971
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2972<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2973<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2974 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2975 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2976 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2977
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2978<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2979<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2980 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2981 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2982 transferred to the corresponding destination; otherwise, control flow is
2983 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2984
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2985<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2986<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2987 <tt>switch</tt> instruction, this instruction may be code generated in
2988 different ways. For example, it could be generated as a series of chained
2989 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2990
2991<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2992<pre>
2993 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2994 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2995 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2996
2997 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2998 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2999
3000 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3001 switch i32 %val, label %otherwise [ i32 0, label %onzero
3002 i32 1, label %onone
3003 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3004</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3005
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3006</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3007
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3008
3009<!-- _______________________________________________________________________ -->
3010<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3011 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3012</div>
3013
3014<div class="doc_text">
3015
3016<h5>Syntax:</h5>
3017<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3018 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]3019</pre>
3020
3021<h5>Overview:</h5>
3022
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3023<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3024 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3025 "<tt>address</tt>". Address must be derived from a <a
3026 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3027
3028<h5>Arguments:</h5>
3029
3030<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3031 rest of the arguments indicate the full set of possible destinations that the
3032 address may point to. Blocks are allowed to occur multiple times in the
3033 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3034
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3035<p>This destination list is required so that dataflow analysis has an accurate
3036 understanding of the CFG.</p>
3037
3038<h5>Semantics:</h5>
3039
3040<p>Control transfers to the block specified in the address argument. All
3041 possible destination blocks must be listed in the label list, otherwise this
3042 instruction has undefined behavior. This implies that jumps to labels
3043 defined in other functions have undefined behavior as well.</p>
3044
3045<h5>Implementation:</h5>
3046
3047<p>This is typically implemented with a jump through a register.</p>
3048
3049<h5>Example:</h5>
3050<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3051 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3052</pre>
3053
3054</div>
3055
3056
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3057<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3058<div class="doc_subsubsection">
3059 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3060</div>
3061
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3062<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3063
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3064<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3065<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3066 &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]3067 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3068</pre>
3069
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3070<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3071<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3072 function, with the possibility of control flow transfer to either the
3073 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3074 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3075 control flow will return to the "normal" label. If the callee (or any
3076 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3077 instruction, control is interrupted and continued at the dynamically nearest
3078 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3079
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3080<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3081<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3082
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3083<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3084 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3085 convention</a> the call should use. If none is specified, the call
3086 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3087
3088 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3089 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3090 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3091
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3092 <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]3093 function value being invoked. In most cases, this is a direct function
3094 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3095 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3096
3097 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3098 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3099
3100 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3101 signature argument types and parameter attributes. All arguments must be
3102 of <a href="#t_firstclass">first class</a> type. If the function
3103 signature indicates the function accepts a variable number of arguments,
3104 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3105
3106 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3107 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3108
3109 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3110 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3111
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3112 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3113 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3114 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3115</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3116
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3117<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3118<p>This instruction is designed to operate as a standard
3119 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3120 primary difference is that it establishes an association with a label, which
3121 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3122
3123<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3124 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3125 exception. Additionally, this is important for implementation of
3126 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3127
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3128<p>For the purposes of the SSA form, the definition of the value returned by the
3129 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3130 block to the "normal" label. If the callee unwinds then no return value is
3131 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3132
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3133<p>Note that the code generator does not yet completely support unwind, and
3134that the invoke/unwind semantics are likely to change in future versions.</p>
3135
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3136<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3137<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3138 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3139 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3140 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3141 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3142</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3143
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3144</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3145
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3146<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3147
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3148<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3149Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3150
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3151<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3152
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3153<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3154<pre>
3155 unwind
3156</pre>
3157
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3158<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3159<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3160 at the first callee in the dynamic call stack which used
3161 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3162 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3163
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3164<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3165<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3166 immediately halt. The dynamic call stack is then searched for the
3167 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3168 Once found, execution continues at the "exceptional" destination block
3169 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3170 instruction in the dynamic call chain, undefined behavior results.</p>
3171
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3172<p>Note that the code generator does not yet completely support unwind, and
3173that the invoke/unwind semantics are likely to change in future versions.</p>
3174
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3175</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3176
3177<!-- _______________________________________________________________________ -->
3178
3179<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3180Instruction</a> </div>
3181
3182<div class="doc_text">
3183
3184<h5>Syntax:</h5>
3185<pre>
3186 unreachable
3187</pre>
3188
3189<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3190<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3191 instruction is used to inform the optimizer that a particular portion of the
3192 code is not reachable. This can be used to indicate that the code after a
3193 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3194
3195<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3196<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3197
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3198</div>
3199
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3200<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3201<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3202
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3203<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3204
3205<p>Binary operators are used to do most of the computation in a program. They
3206 require two operands of the same type, execute an operation on them, and
3207 produce a single value. The operands might represent multiple data, as is
3208 the case with the <a href="#t_vector">vector</a> data type. The result value
3209 has the same type as its operands.</p>
3210
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3211<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3212
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3213</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3214
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3215<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3216<div class="doc_subsubsection">
3217 <a name="i_add">'<tt>add</tt>' Instruction</a>
3218</div>
3219
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3220<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3221
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3222<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3223<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3224 &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]3225 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3226 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3227 &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]3228</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3229
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3230<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3231<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3232
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3233<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3234<p>The two arguments to the '<tt>add</tt>' instruction must
3235 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3236 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3237
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3238<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3239<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3240
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3241<p>If the sum has unsigned overflow, the result returned is the mathematical
3242 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]3243
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3244<p>Because LLVM integers use a two's complement representation, this instruction
3245 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3246
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3247<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3248 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3249 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3250 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3251 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3252
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3253<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3254<pre>
3255 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3256</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3257
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3258</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3259
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3260<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3261<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3262 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3263</div>
3264
3265<div class="doc_text">
3266
3267<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3268<pre>
3269 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3270</pre>
3271
3272<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3273<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3274
3275<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3276<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3277 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3278 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3279
3280<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3281<p>The value produced is the floating point sum of the two operands.</p>
3282
3283<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3284<pre>
3285 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3286</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3287
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3288</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3289
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3290<!-- _______________________________________________________________________ -->
3291<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3292 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3293</div>
3294
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3295<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3296
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3297<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3298<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3299 &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]3300 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3301 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3302 &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]3303</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3304
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3305<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3306<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3307 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3308
3309<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3310 '<tt>neg</tt>' instruction present in most other intermediate
3311 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3312
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3313<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3314<p>The two arguments to the '<tt>sub</tt>' instruction must
3315 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3316 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3317
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3318<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3319<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3320
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3321<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3322 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3323 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3324
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3325<p>Because LLVM integers use a two's complement representation, this instruction
3326 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3327
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3328<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3329 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3330 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3331 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3332 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3333
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3334<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3335<pre>
3336 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3337 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3338</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3339
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3340</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3341
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3342<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3343<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3344 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3345</div>
3346
3347<div class="doc_text">
3348
3349<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3350<pre>
3351 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3352</pre>
3353
3354<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3355<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3356 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3357
3358<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3359 '<tt>fneg</tt>' instruction present in most other intermediate
3360 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3361
3362<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3363<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3364 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3365 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3366
3367<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3368<p>The value produced is the floating point difference of the two operands.</p>
3369
3370<h5>Example:</h5>
3371<pre>
3372 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3373 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3374</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3375
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3376</div>
3377
3378<!-- _______________________________________________________________________ -->
3379<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3380 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3381</div>
3382
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3383<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3384
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3385<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3386<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3387 &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]3388 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3389 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3390 &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]3391</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3392
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3393<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3394<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3395
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3396<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3397<p>The two arguments to the '<tt>mul</tt>' instruction must
3398 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3399 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3400
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3401<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3402<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3403
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3404<p>If the result of the multiplication has unsigned overflow, the result
3405 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3406 width of the result.</p>
3407
3408<p>Because LLVM integers use a two's complement representation, and the result
3409 is the same width as the operands, this instruction returns the correct
3410 result for both signed and unsigned integers. If a full product
3411 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3412 be sign-extended or zero-extended as appropriate to the width of the full
3413 product.</p>
3414
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3415<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3416 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3417 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3418 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3419 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3420
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3421<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3422<pre>
3423 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3424</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3425
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3426</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3427
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3428<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3429<div class="doc_subsubsection">
3430 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3431</div>
3432
3433<div class="doc_text">
3434
3435<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3436<pre>
3437 &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]3438</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3439
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3440<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3441<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3442
3443<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3444<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3445 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3446 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3447
3448<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3449<p>The value produced is the floating point product of the two operands.</p>
3450
3451<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3452<pre>
3453 &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]3454</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3455
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3456</div>
3457
3458<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3459<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3460</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3461
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3462<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3463
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3464<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3465<pre>
3466 &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]3467</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3468
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3469<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3470<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3471
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3472<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3473<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3474 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3475 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3476
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3477<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3478<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3479
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3480<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3481 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3482
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3483<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3484
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3485<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3486<pre>
3487 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3488</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3489
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3490</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3491
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3492<!-- _______________________________________________________________________ -->
3493<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3494</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3495
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3496<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3497
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3498<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3499<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3500 &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]3501 &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]3502</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3503
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3504<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3505<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3506
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3507<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3508<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3509 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3510 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3511
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3512<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3513<p>The value produced is the signed integer quotient of the two operands rounded
3514 towards zero.</p>
3515
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3516<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3517 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3518
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3519<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3520 undefined behavior; this is a rare case, but can occur, for example, by doing
3521 a 32-bit division of -2147483648 by -1.</p>
3522
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3523<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3524 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3525 be rounded or if overflow would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3526
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3527<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3528<pre>
3529 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3530</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3531
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3532</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3533
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3534<!-- _______________________________________________________________________ -->
3535<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3536Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3537
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3538<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3539
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3540<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3541<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3542 &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]3543</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3544
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3545<h5>Overview:</h5>
3546<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3547
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3548<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3549<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3550 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3551 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3552
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3553<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3554<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3555
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3556<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3557<pre>
3558 &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]3559</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3560
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3561</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3562
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3563<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3564<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3565</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3566
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3567<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3568
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3569<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3570<pre>
3571 &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]3572</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3573
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3574<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3575<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3576 division of its two arguments.</p>
3577
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3578<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3579<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3580 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3581 values. Both arguments must have identical types.</p>
3582
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3583<h5>Semantics:</h5>
3584<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3585 This instruction always performs an unsigned division to get the
3586 remainder.</p>
3587
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3588<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3589 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3590
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3591<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3592
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3593<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3594<pre>
3595 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3596</pre>
3597
3598</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3599
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3600<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3601<div class="doc_subsubsection">
3602 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3603</div>
3604
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3605<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3606
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3607<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3608<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3609 &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]3610</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3611
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3612<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3613<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3614 division of its two operands. This instruction can also take
3615 <a href="#t_vector">vector</a> versions of the values in which case the
3616 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3617
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3618<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3619<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3620 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3621 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3622
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3623<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3624<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3625 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3626 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3627 a value. For more information about the difference,
3628 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3629 Math Forum</a>. For a table of how this is implemented in various languages,
3630 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3631 Wikipedia: modulo operation</a>.</p>
3632
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3633<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3634 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3635
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3636<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3637 Overflow also leads to undefined behavior; this is a rare case, but can
3638 occur, for example, by taking the remainder of a 32-bit division of
3639 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3640 lets srem be implemented using instructions that return both the result of
3641 the division and the remainder.)</p>
3642
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3643<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3644<pre>
3645 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3646</pre>
3647
3648</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3649
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3650<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3651<div class="doc_subsubsection">
3652 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3653
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3654<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3655
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3656<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3657<pre>
3658 &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]3659</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3660
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3661<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3662<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3663 its two operands.</p>
3664
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3665<h5>Arguments:</h5>
3666<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3667 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3668 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3669
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3670<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3671<p>This instruction returns the <i>remainder</i> of a division. The remainder
3672 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3673
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3674<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3675<pre>
3676 &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]3677</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3678
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3679</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3680
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3681<!-- ======================================================================= -->
3682<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3683Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3684
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3685<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3686
3687<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3688 program. They are generally very efficient instructions and can commonly be
3689 strength reduced from other instructions. They require two operands of the
3690 same type, execute an operation on them, and produce a single value. The
3691 resulting value is the same type as its operands.</p>
3692
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3693</div>
3694
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3695<!-- _______________________________________________________________________ -->
3696<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3697Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3698
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3699<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3700
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3701<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3702<pre>
3703 &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]3704</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3705
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3706<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3707<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3708 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3709
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3710<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3711<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3712 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3713 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3714
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3715<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3716<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3717 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3718 is (statically or dynamically) negative or equal to or larger than the number
3719 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3720 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3721 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3722
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3723<h5>Example:</h5>
3724<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3725 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3726 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3727 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3728 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3729 &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]3730</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3731
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3732</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3733
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3734<!-- _______________________________________________________________________ -->
3735<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3736Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3737
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3738<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3739
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3740<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3741<pre>
3742 &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]3743</pre>
3744
3745<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3746<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3747 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3748
3749<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3750<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3751 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3752 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3753
3754<h5>Semantics:</h5>
3755<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3756 significant bits of the result will be filled with zero bits after the shift.
3757 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3758 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3759 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3760 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3761
3762<h5>Example:</h5>
3763<pre>
3764 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3765 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3766 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3767 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3768 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3769 &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]3770</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3771
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3772</div>
3773
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3774<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3775<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3776Instruction</a> </div>
3777<div class="doc_text">
3778
3779<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3780<pre>
3781 &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]3782</pre>
3783
3784<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3785<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3786 operand shifted to the right a specified number of bits with sign
3787 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3788
3789<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3790<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3791 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3792 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3793
3794<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3795<p>This instruction always performs an arithmetic shift right operation, The
3796 most significant bits of the result will be filled with the sign bit
3797 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3798 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3799 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3800 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3801
3802<h5>Example:</h5>
3803<pre>
3804 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3805 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3806 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3807 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3808 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3809 &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]3810</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3811
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3812</div>
3813
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3814<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3815<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3816Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3817
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3818<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3819
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3820<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3821<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3822 &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]3823</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3824
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3825<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3826<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3827 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3828
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3829<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3830<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3831 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3832 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3833
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3834<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3835<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3836
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3837<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3838 <tbody>
3839 <tr>
3840 <td>In0</td>
3841 <td>In1</td>
3842 <td>Out</td>
3843 </tr>
3844 <tr>
3845 <td>0</td>
3846 <td>0</td>
3847 <td>0</td>
3848 </tr>
3849 <tr>
3850 <td>0</td>
3851 <td>1</td>
3852 <td>0</td>
3853 </tr>
3854 <tr>
3855 <td>1</td>
3856 <td>0</td>
3857 <td>0</td>
3858 </tr>
3859 <tr>
3860 <td>1</td>
3861 <td>1</td>
3862 <td>1</td>
3863 </tr>
3864 </tbody>
3865</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3866
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3867<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3868<pre>
3869 &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]3870 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3871 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3872</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3873</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3874<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3875<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3876
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3877<div class="doc_text">
3878
3879<h5>Syntax:</h5>
3880<pre>
3881 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3882</pre>
3883
3884<h5>Overview:</h5>
3885<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3886 two operands.</p>
3887
3888<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3889<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3890 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3891 values. Both arguments must have identical types.</p>
3892
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3893<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3894<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3895
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3896<table border="1" cellspacing="0" cellpadding="4">
3897 <tbody>
3898 <tr>
3899 <td>In0</td>
3900 <td>In1</td>
3901 <td>Out</td>
3902 </tr>
3903 <tr>
3904 <td>0</td>
3905 <td>0</td>
3906 <td>0</td>
3907 </tr>
3908 <tr>
3909 <td>0</td>
3910 <td>1</td>
3911 <td>1</td>
3912 </tr>
3913 <tr>
3914 <td>1</td>
3915 <td>0</td>
3916 <td>1</td>
3917 </tr>
3918 <tr>
3919 <td>1</td>
3920 <td>1</td>
3921 <td>1</td>
3922 </tr>
3923 </tbody>
3924</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3925
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3926<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3927<pre>
3928 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3929 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3930 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3931</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3932
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3933</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3934
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3935<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3936<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3937Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3938
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3939<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3940
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3941<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3942<pre>
3943 &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]3944</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3945
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3946<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3947<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3948 its two operands. The <tt>xor</tt> is used to implement the "one's
3949 complement" operation, which is the "~" operator in C.</p>
3950
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3951<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3952<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3953 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3954 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3955
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3956<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3957<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3958
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3959<table border="1" cellspacing="0" cellpadding="4">
3960 <tbody>
3961 <tr>
3962 <td>In0</td>
3963 <td>In1</td>
3964 <td>Out</td>
3965 </tr>
3966 <tr>
3967 <td>0</td>
3968 <td>0</td>
3969 <td>0</td>
3970 </tr>
3971 <tr>
3972 <td>0</td>
3973 <td>1</td>
3974 <td>1</td>
3975 </tr>
3976 <tr>
3977 <td>1</td>
3978 <td>0</td>
3979 <td>1</td>
3980 </tr>
3981 <tr>
3982 <td>1</td>
3983 <td>1</td>
3984 <td>0</td>
3985 </tr>
3986 </tbody>
3987</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3988
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3989<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3990<pre>
3991 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3992 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3993 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3994 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3995</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3996
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3997</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3998
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3999<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4000<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4001 <a name="vectorops">Vector Operations</a>
4002</div>
4003
4004<div class="doc_text">
4005
4006<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4007 target-independent manner. These instructions cover the element-access and
4008 vector-specific operations needed to process vectors effectively. While LLVM
4009 does directly support these vector operations, many sophisticated algorithms
4010 will want to use target-specific intrinsics to take full advantage of a
4011 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4012
4013</div>
4014
4015<!-- _______________________________________________________________________ -->
4016<div class="doc_subsubsection">
4017 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4018</div>
4019
4020<div class="doc_text">
4021
4022<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4023<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4024 &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]4025</pre>
4026
4027<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4028<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4029 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4030
4031
4032<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4033<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4034 of <a href="#t_vector">vector</a> type. The second operand is an index
4035 indicating the position from which to extract the element. The index may be
4036 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4037
4038<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4039<p>The result is a scalar of the same type as the element type of
4040 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4041 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4042 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4043
4044<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4045<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4046 &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]4047</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4048
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4049</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4050
4051<!-- _______________________________________________________________________ -->
4052<div class="doc_subsubsection">
4053 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4054</div>
4055
4056<div class="doc_text">
4057
4058<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4059<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4060 &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]4061</pre>
4062
4063<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4064<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4065 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4066
4067<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4068<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4069 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4070 whose type must equal the element type of the first operand. The third
4071 operand is an index indicating the position at which to insert the value.
4072 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4073
4074<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4075<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4076 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4077 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4078 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4079
4080<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4081<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4082 &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]4083</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4084
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4085</div>
4086
4087<!-- _______________________________________________________________________ -->
4088<div class="doc_subsubsection">
4089 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4090</div>
4091
4092<div class="doc_text">
4093
4094<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4095<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4096 &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]4097</pre>
4098
4099<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4100<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4101 from two input vectors, returning a vector with the same element type as the
4102 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4103
4104<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4105<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4106 with types that match each other. The third argument is a shuffle mask whose
4107 element type is always 'i32'. The result of the instruction is a vector
4108 whose length is the same as the shuffle mask and whose element type is the
4109 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4110
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4111<p>The shuffle mask operand is required to be a constant vector with either
4112 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4113
4114<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4115<p>The elements of the two input vectors are numbered from left to right across
4116 both of the vectors. The shuffle mask operand specifies, for each element of
4117 the result vector, which element of the two input vectors the result element
4118 gets. The element selector may be undef (meaning "don't care") and the
4119 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4120
4121<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4122<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4123 &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]4124 &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]4125 &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]4126 &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]4127 &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]4128 &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]4129 &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]4130 &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]4131</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4132
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4133</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4134
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4135<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4136<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4137 <a name="aggregateops">Aggregate Operations</a>
4138</div>
4139
4140<div class="doc_text">
4141
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4142<p>LLVM supports several instructions for working with
4143 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4144
4145</div>
4146
4147<!-- _______________________________________________________________________ -->
4148<div class="doc_subsubsection">
4149 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4150</div>
4151
4152<div class="doc_text">
4153
4154<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4155<pre>
4156 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4157</pre>
4158
4159<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4160<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4161 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4162
4163<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4164<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4165 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4166 <a href="#t_array">array</a> type. The operands are constant indices to
4167 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4168 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4169
4170<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4171<p>The result is the value at the position in the aggregate specified by the
4172 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4173
4174<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4175<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4176 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4177</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4178
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4179</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4180
4181<!-- _______________________________________________________________________ -->
4182<div class="doc_subsubsection">
4183 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4184</div>
4185
4186<div class="doc_text">
4187
4188<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4189<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4190 &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]4191</pre>
4192
4193<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4194<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4195 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4196
4197<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4198<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4199 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4200 <a href="#t_array">array</a> type. The second operand is a first-class
4201 value to insert. The following operands are constant indices indicating
4202 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]4203 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4204 value to insert must have the same type as the value identified by the
4205 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4206
4207<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4208<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4209 that of <tt>val</tt> except that the value at the position specified by the
4210 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4211
4212<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4213<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4214 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4215 %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]4216</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4217
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4218</div>
4219
4220
4221<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4222<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4223 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4224</div>
4225
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4226<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4227
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4228<p>A key design point of an SSA-based representation is how it represents
4229 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4230 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4231 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4232
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4233</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4234
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4235<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4236<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4237 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4238</div>
4239
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4240<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4241
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4242<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4243<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4244 &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]4245</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4246
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4247<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4248<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4249 currently executing function, to be automatically released when this function
4250 returns to its caller. The object is always allocated in the generic address
4251 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4252
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4253<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4254<p>The '<tt>alloca</tt>' instruction
4255 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4256 runtime stack, returning a pointer of the appropriate type to the program.
4257 If "NumElements" is specified, it is the number of elements allocated,
4258 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4259 specified, the value result of the allocation is guaranteed to be aligned to
4260 at least that boundary. If not specified, or if zero, the target can choose
4261 to align the allocation on any convenient boundary compatible with the
4262 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4263
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4264<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4265
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4266<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4267<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4268 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4269 memory is automatically released when the function returns. The
4270 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4271 variables that must have an address available. When the function returns
4272 (either with the <tt><a href="#i_ret">ret</a></tt>
4273 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4274 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4275
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4276<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4277<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4278 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4279 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4280 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4281 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4282</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4283
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4284</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4285
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4286<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4287<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4288Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4289
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4290<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4291
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4292<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4293<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4294 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4295 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4296 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4297</pre>
4298
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4299<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4300<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4301
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4302<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4303<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4304 from which to load. The pointer must point to
4305 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4306 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4307 number or order of execution of this <tt>load</tt> with other <a
4308 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4309
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4310<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4311 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]4312 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4313 alignment for the target. It is the responsibility of the code emitter to
4314 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4315 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4316 produce less efficient code. An alignment of 1 is always safe.</p>
4317
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4318<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4319 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4320 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4321 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4322 and code generator that this load is not expected to be reused in the cache.
4323 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4324 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4325
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4326<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4327<p>The location of memory pointed to is loaded. If the value being loaded is of
4328 scalar type then the number of bytes read does not exceed the minimum number
4329 of bytes needed to hold all bits of the type. For example, loading an
4330 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4331 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4332 is undefined if the value was not originally written using a store of the
4333 same type.</p>
4334
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4335<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4336<pre>
4337 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4338 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4339 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4340</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4341
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4342</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4343
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4344<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4345<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4346Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4347
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4348<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4349
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4350<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4351<pre>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4352 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4353 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]4354</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4355
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4356<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4357<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4358
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4359<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4360<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4361 and an address at which to store it. The type of the
4362 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4363 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4364 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4365 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4366 order of execution of this <tt>store</tt> with other <a
4367 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4368
4369<p>The optional constant "align" argument specifies the alignment of the
4370 operation (that is, the alignment of the memory address). A value of 0 or an
4371 omitted "align" argument means that the operation has the preferential
4372 alignment for the target. It is the responsibility of the code emitter to
4373 ensure that the alignment information is correct. Overestimating the
4374 alignment results in an undefined behavior. Underestimating the alignment may
4375 produce less efficient code. An alignment of 1 is always safe.</p>
4376
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4377<p>The optional !nontemporal metadata must reference a single metatadata
4378 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4379 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4380 instruction tells the optimizer and code generator that this load is
4381 not expected to be reused in the cache. The code generator may
4382 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4383 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4384
4385
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4386<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4387<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4388 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4389 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4390 does not exceed the minimum number of bytes needed to hold all bits of the
4391 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4392 writing a value of a type like <tt>i20</tt> with a size that is not an
4393 integral number of bytes, it is unspecified what happens to the extra bits
4394 that do not belong to the type, but they will typically be overwritten.</p>
4395
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4396<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4397<pre>
4398 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4399 store i32 3, i32* %ptr <i>; yields {void}</i>
4400 %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]4401</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4402
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4403</div>
4404
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4405<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4406<div class="doc_subsubsection">
4407 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4408</div>
4409
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4410<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4411
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4412<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4413<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4414 &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]4415 &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]4416</pre>
4417
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4418<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4419<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4420 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4421 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4422
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4423<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4424<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4425 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4426 elements of the aggregate object are indexed. The interpretation of each
4427 index is dependent on the type being indexed into. The first index always
4428 indexes the pointer value given as the first argument, the second index
4429 indexes a value of the type pointed to (not necessarily the value directly
4430 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4431 indexed into must be a pointer value, subsequent types can be arrays,
4432 vectors, structs and unions. Note that subsequent types being indexed into
4433 can never be pointers, since that would require loading the pointer before
4434 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4435
4436<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]4437 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4438 integer <b>constants</b> are allowed. When indexing into an array, pointer
4439 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]4440 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4441
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4442<p>For example, let's consider a C code fragment and how it gets compiled to
4443 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4444
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4445<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4446<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4447struct RT {
4448 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4449 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4450 char C;
4451};
4452struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4453 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4454 double Y;
4455 struct RT Z;
4456};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4457
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4458int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4459 return &amp;s[1].Z.B[5][13];
4460}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4461</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4462</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4463
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4464<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4465
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4466<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4467<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4468%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4469%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4470
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4471define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4472entry:
4473 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4474 ret i32* %reg
4475}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4476</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4477</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4478
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4479<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4480<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]4481 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4482 }</tt>' type, a structure. The second index indexes into the third element
4483 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4484 i8 }</tt>' type, another structure. The third index indexes into the second
4485 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4486 array. The two dimensions of the array are subscripted into, yielding an
4487 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4488 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4489
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4490<p>Note that it is perfectly legal to index partially through a structure,
4491 returning a pointer to an inner element. Because of this, the LLVM code for
4492 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4493
4494<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4495 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4496 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4497 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4498 %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]4499 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4500 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4501 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4502 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4503</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4504
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4505<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4506 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4507 base pointer is not an <i>in bounds</i> address of an allocated object,
4508 or if any of the addresses that would be formed by successive addition of
4509 the offsets implied by the indices to the base address with infinitely
4510 precise arithmetic are not an <i>in bounds</i> address of that allocated
4511 object. The <i>in bounds</i> addresses for an allocated object are all
4512 the addresses that point into the object, plus the address one byte past
4513 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4514
4515<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4516 the base address with silently-wrapping two's complement arithmetic, and
4517 the result value of the <tt>getelementptr</tt> may be outside the object
4518 pointed to by the base pointer. The result value may not necessarily be
4519 used to access memory though, even if it happens to point into allocated
4520 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4521 section for more information.</p>
4522
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4523<p>The getelementptr instruction is often confusing. For some more insight into
4524 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4525
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4526<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4527<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4528 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4529 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4530 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4531 %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]4532 <i>; yields i8*:eptr</i>
4533 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4534 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4535 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4536</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4537
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4538</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4539
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4540<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4541<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4542</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4543
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4544<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4545
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4546<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4547 which all take a single operand and a type. They perform various bit
4548 conversions on the operand.</p>
4549
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4550</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4551
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4552<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4553<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4554 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4555</div>
4556<div class="doc_text">
4557
4558<h5>Syntax:</h5>
4559<pre>
4560 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4561</pre>
4562
4563<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4564<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4565 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4566
4567<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4568<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4569 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4570 size and type of the result, which must be
4571 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4572 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4573 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4574
4575<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4576<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4577 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4578 source size must be larger than the destination size, <tt>trunc</tt> cannot
4579 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4580
4581<h5>Example:</h5>
4582<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4583 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4584 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4585 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4586</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4587
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4588</div>
4589
4590<!-- _______________________________________________________________________ -->
4591<div class="doc_subsubsection">
4592 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4593</div>
4594<div class="doc_text">
4595
4596<h5>Syntax:</h5>
4597<pre>
4598 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4599</pre>
4600
4601<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4602<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4603 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4604
4605
4606<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4607<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]4608 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4609 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]4610 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4611 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4612
4613<h5>Semantics:</h5>
4614<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]4615 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4616
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4617<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]4618
4619<h5>Example:</h5>
4620<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4621 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4622 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4623</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4624
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4625</div>
4626
4627<!-- _______________________________________________________________________ -->
4628<div class="doc_subsubsection">
4629 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4630</div>
4631<div class="doc_text">
4632
4633<h5>Syntax:</h5>
4634<pre>
4635 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4636</pre>
4637
4638<h5>Overview:</h5>
4639<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4640
4641<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4642<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]4643 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4644 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]4645 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4646 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4647
4648<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4649<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4650 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4651 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4652
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4653<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]4654
4655<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4656<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4657 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4658 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4659</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4660
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4661</div>
4662
4663<!-- _______________________________________________________________________ -->
4664<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4665 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4666</div>
4667
4668<div class="doc_text">
4669
4670<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4671<pre>
4672 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4673</pre>
4674
4675<h5>Overview:</h5>
4676<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4677 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4678
4679<h5>Arguments:</h5>
4680<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4681 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4682 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]4683 <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]4684 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4685
4686<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4687<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4688 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4689 <a href="#t_floating">floating point</a> type. If the value cannot fit
4690 within the destination type, <tt>ty2</tt>, then the results are
4691 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4692
4693<h5>Example:</h5>
4694<pre>
4695 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4696 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4697</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4698
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4699</div>
4700
4701<!-- _______________________________________________________________________ -->
4702<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4703 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4704</div>
4705<div class="doc_text">
4706
4707<h5>Syntax:</h5>
4708<pre>
4709 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4710</pre>
4711
4712<h5>Overview:</h5>
4713<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]4714 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4715
4716<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4717<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4718 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4719 a <a href="#t_floating">floating point</a> type to cast it to. The source
4720 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4721
4722<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4723<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4724 <a href="#t_floating">floating point</a> type to a larger
4725 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4726 used to make a <i>no-op cast</i> because it always changes bits. Use
4727 <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]4728
4729<h5>Example:</h5>
4730<pre>
4731 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4732 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4733</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4734
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4735</div>
4736
4737<!-- _______________________________________________________________________ -->
4738<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4739 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4740</div>
4741<div class="doc_text">
4742
4743<h5>Syntax:</h5>
4744<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4745 &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]4746</pre>
4747
4748<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4749<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4750 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4751
4752<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4753<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4754 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4755 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4756 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4757 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4758
4759<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4760<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4761 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4762 towards zero) unsigned integer value. If the value cannot fit
4763 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4764
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4765<h5>Example:</h5>
4766<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4767 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4768 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4769 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4770</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4771
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4772</div>
4773
4774<!-- _______________________________________________________________________ -->
4775<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4776 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4777</div>
4778<div class="doc_text">
4779
4780<h5>Syntax:</h5>
4781<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4782 &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]4783</pre>
4784
4785<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4786<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4787 <a href="#t_floating">floating point</a> <tt>value</tt> to
4788 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4789
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4790<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4791<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4792 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4793 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4794 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4795 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4796
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4797<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4798<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4799 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4800 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4801 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4802
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4803<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4804<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4805 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4806 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4807 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4808</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4809
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4810</div>
4811
4812<!-- _______________________________________________________________________ -->
4813<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4814 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4815</div>
4816<div class="doc_text">
4817
4818<h5>Syntax:</h5>
4819<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4820 &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]4821</pre>
4822
4823<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4824<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4825 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4826
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4827<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4828<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]4829 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4830 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4831 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4832 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4833
4834<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4835<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4836 integer quantity and converts it to the corresponding floating point
4837 value. If the value cannot fit in the floating point value, the results are
4838 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4839
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4840<h5>Example:</h5>
4841<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4842 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4843 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4844</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4845
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4846</div>
4847
4848<!-- _______________________________________________________________________ -->
4849<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4850 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4851</div>
4852<div class="doc_text">
4853
4854<h5>Syntax:</h5>
4855<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4856 &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]4857</pre>
4858
4859<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4860<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4861 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4862
4863<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4864<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]4865 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4866 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4867 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4868 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4869
4870<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4871<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4872 quantity and converts it to the corresponding floating point value. If the
4873 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4874
4875<h5>Example:</h5>
4876<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4877 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4878 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4879</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4880
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4881</div>
4882
4883<!-- _______________________________________________________________________ -->
4884<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4885 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4886</div>
4887<div class="doc_text">
4888
4889<h5>Syntax:</h5>
4890<pre>
4891 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4892</pre>
4893
4894<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4895<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4896 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4897
4898<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4899<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4900 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4901 <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]4902
4903<h5>Semantics:</h5>
4904<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4905 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4906 truncating or zero extending that value to the size of the integer type. If
4907 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4908 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4909 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4910 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4911
4912<h5>Example:</h5>
4913<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4914 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4915 %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]4916</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4917
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4918</div>
4919
4920<!-- _______________________________________________________________________ -->
4921<div class="doc_subsubsection">
4922 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4923</div>
4924<div class="doc_text">
4925
4926<h5>Syntax:</h5>
4927<pre>
4928 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4929</pre>
4930
4931<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4932<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4933 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4934
4935<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4936<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4937 value to cast, and a type to cast it to, which must be a
4938 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4939
4940<h5>Semantics:</h5>
4941<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4942 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4943 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4944 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4945 than the size of a pointer then a zero extension is done. If they are the
4946 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4947
4948<h5>Example:</h5>
4949<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4950 %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]4951 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4952 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4953</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4954
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4955</div>
4956
4957<!-- _______________________________________________________________________ -->
4958<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4959 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4960</div>
4961<div class="doc_text">
4962
4963<h5>Syntax:</h5>
4964<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4965 &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]4966</pre>
4967
4968<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4969<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4970 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4971
4972<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4973<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4974 non-aggregate first class value, and a type to cast it to, which must also be
4975 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4976 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4977 identical. If the source type is a pointer, the destination type must also be
4978 a pointer. This instruction supports bitwise conversion of vectors to
4979 integers and to vectors of other types (as long as they have the same
4980 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4981
4982<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4983<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4984 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4985 this conversion. The conversion is done as if the <tt>value</tt> had been
4986 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4987 be converted to other pointer types with this instruction. To convert
4988 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4989 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4990
4991<h5>Example:</h5>
4992<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4993 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4994 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4995 %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]4996</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4997
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4998</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4999
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5000<!-- ======================================================================= -->
5001<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5002
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5003<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5004
5005<p>The instructions in this category are the "miscellaneous" instructions, which
5006 defy better classification.</p>
5007
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5008</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5009
5010<!-- _______________________________________________________________________ -->
5011<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5012</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5013
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5014<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5015
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5016<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5017<pre>
5018 &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]5019</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5020
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5021<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5022<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5023 boolean values based on comparison of its two integer, integer vector, or
5024 pointer operands.</p>
5025
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5026<h5>Arguments:</h5>
5027<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5028 the condition code indicating the kind of comparison to perform. It is not a
5029 value, just a keyword. The possible condition code are:</p>
5030
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5031<ol>
5032 <li><tt>eq</tt>: equal</li>
5033 <li><tt>ne</tt>: not equal </li>
5034 <li><tt>ugt</tt>: unsigned greater than</li>
5035 <li><tt>uge</tt>: unsigned greater or equal</li>
5036 <li><tt>ult</tt>: unsigned less than</li>
5037 <li><tt>ule</tt>: unsigned less or equal</li>
5038 <li><tt>sgt</tt>: signed greater than</li>
5039 <li><tt>sge</tt>: signed greater or equal</li>
5040 <li><tt>slt</tt>: signed less than</li>
5041 <li><tt>sle</tt>: signed less or equal</li>
5042</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5043
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5044<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5045 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5046 typed. They must also be identical types.</p>
5047
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5048<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5049<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5050 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5051 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]5052 result, as follows:</p>
5053
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5054<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5055 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5056 <tt>false</tt> otherwise. No sign interpretation is necessary or
5057 performed.</li>
5058
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5059 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5060 <tt>false</tt> otherwise. No sign interpretation is necessary or
5061 performed.</li>
5062
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5063 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5064 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5065
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5066 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5067 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5068 to <tt>op2</tt>.</li>
5069
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5070 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5071 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5072
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5073 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5074 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5075
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5076 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5077 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5078
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5079 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5080 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5081 to <tt>op2</tt>.</li>
5082
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5083 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5084 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5085
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5086 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5087 <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]5088</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5089
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5090<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5091 values are compared as if they were integers.</p>
5092
5093<p>If the operands are integer vectors, then they are compared element by
5094 element. The result is an <tt>i1</tt> vector with the same number of elements
5095 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5096
5097<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5098<pre>
5099 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5100 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5101 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5102 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5103 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5104 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5105</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5106
5107<p>Note that the code generator does not yet support vector types with
5108 the <tt>icmp</tt> instruction.</p>
5109
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5110</div>
5111
5112<!-- _______________________________________________________________________ -->
5113<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5114</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5115
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5116<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5117
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5118<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5119<pre>
5120 &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]5121</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5122
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5123<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5124<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5125 values based on comparison of its operands.</p>
5126
5127<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]5128(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5129
5130<p>If the operands are floating point vectors, then the result type is a vector
5131 of boolean with the same number of elements as the operands being
5132 compared.</p>
5133
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5134<h5>Arguments:</h5>
5135<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5136 the condition code indicating the kind of comparison to perform. It is not a
5137 value, just a keyword. The possible condition code are:</p>
5138
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5139<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5140 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5141 <li><tt>oeq</tt>: ordered and equal</li>
5142 <li><tt>ogt</tt>: ordered and greater than </li>
5143 <li><tt>oge</tt>: ordered and greater than or equal</li>
5144 <li><tt>olt</tt>: ordered and less than </li>
5145 <li><tt>ole</tt>: ordered and less than or equal</li>
5146 <li><tt>one</tt>: ordered and not equal</li>
5147 <li><tt>ord</tt>: ordered (no nans)</li>
5148 <li><tt>ueq</tt>: unordered or equal</li>
5149 <li><tt>ugt</tt>: unordered or greater than </li>
5150 <li><tt>uge</tt>: unordered or greater than or equal</li>
5151 <li><tt>ult</tt>: unordered or less than </li>
5152 <li><tt>ule</tt>: unordered or less than or equal</li>
5153 <li><tt>une</tt>: unordered or not equal</li>
5154 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5155 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5156</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5157
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5158<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5159 <i>unordered</i> means that either operand may be a QNAN.</p>
5160
5161<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5162 a <a href="#t_floating">floating point</a> type or
5163 a <a href="#t_vector">vector</a> of floating point type. They must have
5164 identical types.</p>
5165
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5166<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5167<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5168 according to the condition code given as <tt>cond</tt>. If the operands are
5169 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5170 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5171 follows:</p>
5172
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5173<ol>
5174 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5175
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5176 <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]5177 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5178
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5179 <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]5180 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5181
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5182 <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]5183 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5184
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5185 <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]5186 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5187
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5188 <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]5189 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5190
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5191 <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]5192 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5193
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5194 <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]5195
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5196 <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]5197 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5198
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5199 <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]5200 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5201
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5202 <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]5203 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5204
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5205 <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]5206 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5207
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5208 <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]5209 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5210
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5211 <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]5212 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5213
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5214 <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]5215
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5216 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5217</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5218
5219<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5220<pre>
5221 &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]5222 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5223 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5224 &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]5225</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5226
5227<p>Note that the code generator does not yet support vector types with
5228 the <tt>fcmp</tt> instruction.</p>
5229
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5230</div>
5231
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5232<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5233<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5234 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5235</div>
5236
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5237<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5238
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5239<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5240<pre>
5241 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5242</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5243
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5244<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5245<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5246 SSA graph representing the function.</p>
5247
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5248<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5249<p>The type of the incoming values is specified with the first type field. After
5250 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5251 one pair for each predecessor basic block of the current block. Only values
5252 of <a href="#t_firstclass">first class</a> type may be used as the value
5253 arguments to the PHI node. Only labels may be used as the label
5254 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5255
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5256<p>There must be no non-phi instructions between the start of a basic block and
5257 the PHI instructions: i.e. PHI instructions must be first in a basic
5258 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5259
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5260<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5261 occur on the edge from the corresponding predecessor block to the current
5262 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5263 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5264
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5265<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5266<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5267 specified by the pair corresponding to the predecessor basic block that
5268 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5269
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5270<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5271<pre>
5272Loop: ; Infinite loop that counts from 0 on up...
5273 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5274 %nextindvar = add i32 %indvar, 1
5275 br label %Loop
5276</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5277
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5278</div>
5279
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5280<!-- _______________________________________________________________________ -->
5281<div class="doc_subsubsection">
5282 <a name="i_select">'<tt>select</tt>' Instruction</a>
5283</div>
5284
5285<div class="doc_text">
5286
5287<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5288<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5289 &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>
5290
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5291 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5292</pre>
5293
5294<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5295<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5296 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5297
5298
5299<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5300<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5301 values indicating the condition, and two values of the
5302 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5303 vectors and the condition is a scalar, then entire vectors are selected, not
5304 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5305
5306<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5307<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5308 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5309
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5310<p>If the condition is a vector of i1, then the value arguments must be vectors
5311 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5312
5313<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5314<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5315 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5316</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5317
5318<p>Note that the code generator does not yet support conditions
5319 with vector type.</p>
5320
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5321</div>
5322
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5323<!-- _______________________________________________________________________ -->
5324<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5325 <a name="i_call">'<tt>call</tt>' Instruction</a>
5326</div>
5327
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5328<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5329
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5330<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5331<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5332 &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]5333</pre>
5334
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5335<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5336<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5337
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5338<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5339<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5340
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5341<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5342 <li>The optional "tail" marker indicates that the callee function does not
5343 access any allocas or varargs in the caller. Note that calls may be
5344 marked "tail" even if they do not occur before
5345 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5346 present, the function call is eligible for tail call optimization,
5347 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5348 optimized into a jump</a>. The code generator may optimize calls marked
5349 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5350 sibling call optimization</a> when the caller and callee have
5351 matching signatures, or 2) forced tail call optimization when the
5352 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5353 <ul>
5354 <li>Caller and callee both have the calling
5355 convention <tt>fastcc</tt>.</li>
5356 <li>The call is in tail position (ret immediately follows call and ret
5357 uses value of call or is void).</li>
5358 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5359 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5360 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5361 constraints are met.</a></li>
5362 </ul>
5363 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5364
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5365 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5366 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5367 defaults to using C calling conventions. The calling convention of the
5368 call must match the calling convention of the target function, or else the
5369 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5370
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5371 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5372 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5373 '<tt>inreg</tt>' attributes are valid here.</li>
5374
5375 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5376 type of the return value. Functions that return no value are marked
5377 <tt><a href="#t_void">void</a></tt>.</li>
5378
5379 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5380 being invoked. The argument types must match the types implied by this
5381 signature. This type can be omitted if the function is not varargs and if
5382 the function type does not return a pointer to a function.</li>
5383
5384 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5385 be invoked. In most cases, this is a direct function invocation, but
5386 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5387 to function value.</li>
5388
5389 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5390 signature argument types and parameter attributes. All arguments must be
5391 of <a href="#t_firstclass">first class</a> type. If the function
5392 signature indicates the function accepts a variable number of arguments,
5393 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5394
5395 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5396 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5397 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5398</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5399
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5400<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5401<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5402 a specified function, with its incoming arguments bound to the specified
5403 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5404 function, control flow continues with the instruction after the function
5405 call, and the return value of the function is bound to the result
5406 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5407
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5408<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5409<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5410 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5411 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5412 %X = tail call i32 @foo() <i>; yields i32</i>
5413 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5414 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5415
5416 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5417 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5418 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5419 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5420 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5421 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5422</pre>
5423
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5424<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5425standard C99 library as being the C99 library functions, and may perform
5426optimizations or generate code for them under that assumption. This is
5427something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5428freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5429
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5430</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5431
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5432<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5433<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5434 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5435</div>
5436
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5437<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5438
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5439<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5440<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5441 &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]5442</pre>
5443
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5444<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5445<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5446 the "variable argument" area of a function call. It is used to implement the
5447 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5448
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5449<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5450<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5451 argument. It returns a value of the specified argument type and increments
5452 the <tt>va_list</tt> to point to the next argument. The actual type
5453 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5454
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5455<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5456<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5457 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5458 to the next argument. For more information, see the variable argument
5459 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5460
5461<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]5462 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5463 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5464
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5465<p><tt>va_arg</tt> is an LLVM instruction instead of
5466 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5467 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5468
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5469<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5470<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5471
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5472<p>Note that the code generator does not yet fully support va_arg on many
5473 targets. Also, it does not currently support va_arg with aggregate types on
5474 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5475
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5476</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5477
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5478<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5479<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5480<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5481
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5482<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5483
5484<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5485 well known names and semantics and are required to follow certain
5486 restrictions. Overall, these intrinsics represent an extension mechanism for
5487 the LLVM language that does not require changing all of the transformations
5488 in LLVM when adding to the language (or the bitcode reader/writer, the
5489 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5490
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5491<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5492 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5493 begin with this prefix. Intrinsic functions must always be external
5494 functions: you cannot define the body of intrinsic functions. Intrinsic
5495 functions may only be used in call or invoke instructions: it is illegal to
5496 take the address of an intrinsic function. Additionally, because intrinsic
5497 functions are part of the LLVM language, it is required if any are added that
5498 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5499
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5500<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5501 family of functions that perform the same operation but on different data
5502 types. Because LLVM can represent over 8 million different integer types,
5503 overloading is used commonly to allow an intrinsic function to operate on any
5504 integer type. One or more of the argument types or the result type can be
5505 overloaded to accept any integer type. Argument types may also be defined as
5506 exactly matching a previous argument's type or the result type. This allows
5507 an intrinsic function which accepts multiple arguments, but needs all of them
5508 to be of the same type, to only be overloaded with respect to a single
5509 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5510
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5511<p>Overloaded intrinsics will have the names of its overloaded argument types
5512 encoded into its function name, each preceded by a period. Only those types
5513 which are overloaded result in a name suffix. Arguments whose type is matched
5514 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5515 can take an integer of any width and returns an integer of exactly the same
5516 integer width. This leads to a family of functions such as
5517 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5518 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5519 suffix is required. Because the argument's type is matched against the return
5520 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5521
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5522<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5523 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5524
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5525</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5526
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5527<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5528<div class="doc_subsection">
5529 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5530</div>
5531
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5532<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5533
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5534<p>Variable argument support is defined in LLVM with
5535 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5536 intrinsic functions. These functions are related to the similarly named
5537 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5538
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5539<p>All of these functions operate on arguments that use a target-specific value
5540 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5541 not define what this type is, so all transformations should be prepared to
5542 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5543
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5544<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]5545 instruction and the variable argument handling intrinsic functions are
5546 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5547
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5548<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5549<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5550define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5551 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5552 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5553 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5554 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5555
5556 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5557 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5558
5559 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5560 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5561 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5562 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5563 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5564
5565 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5566 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5567 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5568}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5569
5570declare void @llvm.va_start(i8*)
5571declare void @llvm.va_copy(i8*, i8*)
5572declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5573</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5574</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5575
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5576</div>
5577
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5578<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5579<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5580 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5581</div>
5582
5583
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5584<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5585
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5586<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5587<pre>
5588 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5589</pre>
5590
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5591<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5592<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5593 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]5594
5595<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5596<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]5597
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5598<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5599<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]5600 macro available in C. In a target-dependent way, it initializes
5601 the <tt>va_list</tt> element to which the argument points, so that the next
5602 call to <tt>va_arg</tt> will produce the first variable argument passed to
5603 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5604 need to know the last argument of the function as the compiler can figure
5605 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5606
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5607</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5608
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5609<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5610<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5611 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5612</div>
5613
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5614<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5615
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5616<h5>Syntax:</h5>
5617<pre>
5618 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5619</pre>
5620
5621<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5622<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5623 which has been initialized previously
5624 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5625 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5626
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5627<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5628<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]5629
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5630<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5631<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]5632 macro available in C. In a target-dependent way, it destroys
5633 the <tt>va_list</tt> element to which the argument points. Calls
5634 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5635 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5636 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5637
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5638</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5639
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5640<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5641<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5642 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5643</div>
5644
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5645<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5646
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5647<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5648<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5649 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5650</pre>
5651
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5652<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5653<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5654 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5655
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5656<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5657<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]5658 The second argument is a pointer to a <tt>va_list</tt> element to copy
5659 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5660
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5661<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5662<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]5663 macro available in C. In a target-dependent way, it copies the
5664 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5665 element. This intrinsic is necessary because
5666 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5667 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5668
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5669</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5670
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5671<!-- ======================================================================= -->
5672<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5673 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5674</div>
5675
5676<div class="doc_text">
5677
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5678<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5679Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5680intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5681roots on the stack</a>, as well as garbage collector implementations that
5682require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5683barriers. Front-ends for type-safe garbage collected languages should generate
5684these intrinsics to make use of the LLVM garbage collectors. For more details,
5685see <a href="GarbageCollection.html">Accurate Garbage Collection with
5686LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5687
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5688<p>The garbage collection intrinsics only operate on objects in the generic
5689 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5690
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5691</div>
5692
5693<!-- _______________________________________________________________________ -->
5694<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5695 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5696</div>
5697
5698<div class="doc_text">
5699
5700<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5701<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5702 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5703</pre>
5704
5705<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5706<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]5707 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5708
5709<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5710<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5711 root pointer. The second pointer (which must be either a constant or a
5712 global value address) contains the meta-data to be associated with the
5713 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5714
5715<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5716<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]5717 location. At compile-time, the code generator generates information to allow
5718 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5719 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5720 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5721
5722</div>
5723
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5724<!-- _______________________________________________________________________ -->
5725<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5726 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5727</div>
5728
5729<div class="doc_text">
5730
5731<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5732<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5733 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5734</pre>
5735
5736<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5737<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5738 locations, allowing garbage collector implementations that require read
5739 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5740
5741<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5742<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]5743 allocated from the garbage collector. The first object is a pointer to the
5744 start of the referenced object, if needed by the language runtime (otherwise
5745 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5746
5747<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5748<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5749 instruction, but may be replaced with substantially more complex code by the
5750 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5751 may only be used in a function which <a href="#gc">specifies a GC
5752 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5753
5754</div>
5755
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5756<!-- _______________________________________________________________________ -->
5757<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5758 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5759</div>
5760
5761<div class="doc_text">
5762
5763<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5764<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5765 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5766</pre>
5767
5768<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5769<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5770 locations, allowing garbage collector implementations that require write
5771 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5772
5773<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5774<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]5775 object to store it to, and the third is the address of the field of Obj to
5776 store to. If the runtime does not require a pointer to the object, Obj may
5777 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5778
5779<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5780<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5781 instruction, but may be replaced with substantially more complex code by the
5782 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5783 may only be used in a function which <a href="#gc">specifies a GC
5784 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5785
5786</div>
5787
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5788<!-- ======================================================================= -->
5789<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5790 <a name="int_codegen">Code Generator Intrinsics</a>
5791</div>
5792
5793<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5794
5795<p>These intrinsics are provided by LLVM to expose special features that may
5796 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5797
5798</div>
5799
5800<!-- _______________________________________________________________________ -->
5801<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5802 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5803</div>
5804
5805<div class="doc_text">
5806
5807<h5>Syntax:</h5>
5808<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5809 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5810</pre>
5811
5812<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5813<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5814 target-specific value indicating the return address of the current function
5815 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5816
5817<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5818<p>The argument to this intrinsic indicates which function to return the address
5819 for. Zero indicates the calling function, one indicates its caller, etc.
5820 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5821
5822<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5823<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5824 indicating the return address of the specified call frame, or zero if it
5825 cannot be identified. The value returned by this intrinsic is likely to be
5826 incorrect or 0 for arguments other than zero, so it should only be used for
5827 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5828
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5829<p>Note that calling this intrinsic does not prevent function inlining or other
5830 aggressive transformations, so the value returned may not be that of the
5831 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5832
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5833</div>
5834
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5835<!-- _______________________________________________________________________ -->
5836<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5837 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5838</div>
5839
5840<div class="doc_text">
5841
5842<h5>Syntax:</h5>
5843<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5844 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5845</pre>
5846
5847<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5848<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5849 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5850
5851<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5852<p>The argument to this intrinsic indicates which function to return the frame
5853 pointer for. Zero indicates the calling function, one indicates its caller,
5854 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5855
5856<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5857<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5858 indicating the frame address of the specified call frame, or zero if it
5859 cannot be identified. The value returned by this intrinsic is likely to be
5860 incorrect or 0 for arguments other than zero, so it should only be used for
5861 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5862
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5863<p>Note that calling this intrinsic does not prevent function inlining or other
5864 aggressive transformations, so the value returned may not be that of the
5865 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5866
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5867</div>
5868
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5869<!-- _______________________________________________________________________ -->
5870<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5871 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5872</div>
5873
5874<div class="doc_text">
5875
5876<h5>Syntax:</h5>
5877<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5878 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5879</pre>
5880
5881<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5882<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5883 of the function stack, for use
5884 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5885 useful for implementing language features like scoped automatic variable
5886 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5887
5888<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5889<p>This intrinsic returns a opaque pointer value that can be passed
5890 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5891 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5892 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5893 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5894 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5895 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5896
5897</div>
5898
5899<!-- _______________________________________________________________________ -->
5900<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5901 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5902</div>
5903
5904<div class="doc_text">
5905
5906<h5>Syntax:</h5>
5907<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5908 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5909</pre>
5910
5911<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5912<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5913 the function stack to the state it was in when the
5914 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5915 executed. This is useful for implementing language features like scoped
5916 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5917
5918<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5919<p>See the description
5920 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5921
5922</div>
5923
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5924<!-- _______________________________________________________________________ -->
5925<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5926 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5927</div>
5928
5929<div class="doc_text">
5930
5931<h5>Syntax:</h5>
5932<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5933 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]5934</pre>
5935
5936<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5937<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5938 insert a prefetch instruction if supported; otherwise, it is a noop.
5939 Prefetches have no effect on the behavior of the program but can change its
5940 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5941
5942<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5943<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5944 specifier determining if the fetch should be for a read (0) or write (1),
5945 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5946 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5947 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5948
5949<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5950<p>This intrinsic does not modify the behavior of the program. In particular,
5951 prefetches cannot trap and do not produce a value. On targets that support
5952 this intrinsic, the prefetch can provide hints to the processor cache for
5953 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5954
5955</div>
5956
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5957<!-- _______________________________________________________________________ -->
5958<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5959 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5960</div>
5961
5962<div class="doc_text">
5963
5964<h5>Syntax:</h5>
5965<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5966 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5967</pre>
5968
5969<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5970<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5971 Counter (PC) in a region of code to simulators and other tools. The method
5972 is target specific, but it is expected that the marker will use exported
5973 symbols to transmit the PC of the marker. The marker makes no guarantees
5974 that it will remain with any specific instruction after optimizations. It is
5975 possible that the presence of a marker will inhibit optimizations. The
5976 intended use is to be inserted after optimizations to allow correlations of
5977 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5978
5979<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5980<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5981
5982<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5983<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5984 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5985
5986</div>
5987
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5988<!-- _______________________________________________________________________ -->
5989<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5990 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5991</div>
5992
5993<div class="doc_text">
5994
5995<h5>Syntax:</h5>
5996<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5997 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5998</pre>
5999
6000<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6001<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6002 counter register (or similar low latency, high accuracy clocks) on those
6003 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6004 should map to RPCC. As the backing counters overflow quickly (on the order
6005 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6006
6007<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6008<p>When directly supported, reading the cycle counter should not modify any
6009 memory. Implementations are allowed to either return a application specific
6010 value or a system wide value. On backends without support, this is lowered
6011 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6012
6013</div>
6014
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6015<!-- ======================================================================= -->
6016<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6017 <a name="int_libc">Standard C Library Intrinsics</a>
6018</div>
6019
6020<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6021
6022<p>LLVM provides intrinsics for a few important standard C library functions.
6023 These intrinsics allow source-language front-ends to pass information about
6024 the alignment of the pointer arguments to the code generator, providing
6025 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6026
6027</div>
6028
6029<!-- _______________________________________________________________________ -->
6030<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6031 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6032</div>
6033
6034<div class="doc_text">
6035
6036<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6037<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6038 integer bit width and for different address spaces. Not all targets support
6039 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6040
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6041<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6042 declare void @llvm.memcpy.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6043 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6044 declare void @llvm.memcpy.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6045 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6046</pre>
6047
6048<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6049<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6050 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6051
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6052<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6053 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6054 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6055
6056<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6057
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6058<p>The first argument is a pointer to the destination, the second is a pointer
6059 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6060 number of bytes to copy, the fourth argument is the alignment of the
6061 source and destination locations, and the fifth is a boolean indicating a
6062 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6063
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6064<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]6065 then the caller guarantees that both the source and destination pointers are
6066 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6067
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6068<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6069 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6070 The detailed access behavior is not very cleanly specified and it is unwise
6071 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6072
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6073<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6074
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6075<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6076 source location to the destination location, which are not allowed to
6077 overlap. It copies "len" bytes of memory over. If the argument is known to
6078 be aligned to some boundary, this can be specified as the fourth argument,
6079 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6080
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6081</div>
6082
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6083<!-- _______________________________________________________________________ -->
6084<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6085 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6086</div>
6087
6088<div class="doc_text">
6089
6090<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6091<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]6092 width and for different address space. Not all targets support all bit
6093 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6094
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6095<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6096 declare void @llvm.memmove.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6097 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6098 declare void @llvm.memmove.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6099 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6100</pre>
6101
6102<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6103<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6104 source location to the destination location. It is similar to the
6105 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6106 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6107
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6108<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6109 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6110 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6111
6112<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6113
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6114<p>The first argument is a pointer to the destination, the second is a pointer
6115 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6116 number of bytes to copy, the fourth argument is the alignment of the
6117 source and destination locations, and the fifth is a boolean indicating a
6118 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6119
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6120<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]6121 then the caller guarantees that the source and destination pointers are
6122 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6123
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6124<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6125 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6126 The detailed access behavior is not very cleanly specified and it is unwise
6127 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6128
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6129<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6130
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6131<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6132 source location to the destination location, which may overlap. It copies
6133 "len" bytes of memory over. If the argument is known to be aligned to some
6134 boundary, this can be specified as the fourth argument, otherwise it should
6135 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6136
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6137</div>
6138
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6139<!-- _______________________________________________________________________ -->
6140<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6141 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6142</div>
6143
6144<div class="doc_text">
6145
6146<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6147<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]6148 width and for different address spaces. Not all targets support all bit
6149 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6150
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6151<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6152 declare void @llvm.memset.p0i8.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6153 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6154 declare void @llvm.memset.p0i8.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6155 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6156</pre>
6157
6158<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6159<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6160 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6161
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6162<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6163 intrinsic does not return a value, takes extra alignment/volatile arguments,
6164 and the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6165
6166<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6167<p>The first argument is a pointer to the destination to fill, the second is the
6168 byte value to fill it with, the third argument is an integer argument
6169 specifying the number of bytes to fill, and the fourth argument is the known
6170 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6171
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6172<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]6173 then the caller guarantees that the destination pointer is aligned to that
6174 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6175
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6176<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6177 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6178 The detailed access behavior is not very cleanly specified and it is unwise
6179 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6180
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6181<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6182<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6183 at the destination location. If the argument is known to be aligned to some
6184 boundary, this can be specified as the fourth argument, otherwise it should
6185 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6186
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6187</div>
6188
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6189<!-- _______________________________________________________________________ -->
6190<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6191 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6192</div>
6193
6194<div class="doc_text">
6195
6196<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6197<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6198 floating point or vector of floating point type. Not all targets support all
6199 types however.</p>
6200
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6201<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6202 declare float @llvm.sqrt.f32(float %Val)
6203 declare double @llvm.sqrt.f64(double %Val)
6204 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6205 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6206 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6207</pre>
6208
6209<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6210<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6211 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6212 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6213 behavior for negative numbers other than -0.0 (which allows for better
6214 optimization, because there is no need to worry about errno being
6215 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]6216
6217<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6218<p>The argument and return value are floating point numbers of the same
6219 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6220
6221<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6222<p>This function returns the sqrt of the specified operand if it is a
6223 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6224
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6225</div>
6226
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6227<!-- _______________________________________________________________________ -->
6228<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6229 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6230</div>
6231
6232<div class="doc_text">
6233
6234<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6235<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6236 floating point or vector of floating point type. Not all targets support all
6237 types however.</p>
6238
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6239<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6240 declare float @llvm.powi.f32(float %Val, i32 %power)
6241 declare double @llvm.powi.f64(double %Val, i32 %power)
6242 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6243 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6244 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6245</pre>
6246
6247<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6248<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6249 specified (positive or negative) power. The order of evaluation of
6250 multiplications is not defined. When a vector of floating point type is
6251 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6252
6253<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6254<p>The second argument is an integer power, and the first is a value to raise to
6255 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6256
6257<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6258<p>This function returns the first value raised to the second power with an
6259 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6260
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6261</div>
6262
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6263<!-- _______________________________________________________________________ -->
6264<div class="doc_subsubsection">
6265 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6266</div>
6267
6268<div class="doc_text">
6269
6270<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6271<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6272 floating point or vector of floating point type. Not all targets support all
6273 types however.</p>
6274
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6275<pre>
6276 declare float @llvm.sin.f32(float %Val)
6277 declare double @llvm.sin.f64(double %Val)
6278 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6279 declare fp128 @llvm.sin.f128(fp128 %Val)
6280 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6281</pre>
6282
6283<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6284<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6285
6286<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6287<p>The argument and return value are floating point numbers of the same
6288 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6289
6290<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6291<p>This function returns the sine of the specified operand, returning the same
6292 values as the libm <tt>sin</tt> functions would, and handles error conditions
6293 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6294
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6295</div>
6296
6297<!-- _______________________________________________________________________ -->
6298<div class="doc_subsubsection">
6299 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6300</div>
6301
6302<div class="doc_text">
6303
6304<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6305<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6306 floating point or vector of floating point type. Not all targets support all
6307 types however.</p>
6308
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6309<pre>
6310 declare float @llvm.cos.f32(float %Val)
6311 declare double @llvm.cos.f64(double %Val)
6312 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6313 declare fp128 @llvm.cos.f128(fp128 %Val)
6314 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6315</pre>
6316
6317<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6318<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6319
6320<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6321<p>The argument and return value are floating point numbers of the same
6322 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6323
6324<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6325<p>This function returns the cosine of the specified operand, returning the same
6326 values as the libm <tt>cos</tt> functions would, and handles error conditions
6327 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6328
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6329</div>
6330
6331<!-- _______________________________________________________________________ -->
6332<div class="doc_subsubsection">
6333 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6334</div>
6335
6336<div class="doc_text">
6337
6338<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6339<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6340 floating point or vector of floating point type. Not all targets support all
6341 types however.</p>
6342
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6343<pre>
6344 declare float @llvm.pow.f32(float %Val, float %Power)
6345 declare double @llvm.pow.f64(double %Val, double %Power)
6346 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6347 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6348 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6349</pre>
6350
6351<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6352<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6353 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6354
6355<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6356<p>The second argument is a floating point power, and the first is a value to
6357 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6358
6359<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6360<p>This function returns the first value raised to the second power, returning
6361 the same values as the libm <tt>pow</tt> functions would, and handles error
6362 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6363
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6364</div>
6365
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6366<!-- ======================================================================= -->
6367<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6368 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6369</div>
6370
6371<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6372
6373<p>LLVM provides intrinsics for a few important bit manipulation operations.
6374 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6375
6376</div>
6377
6378<!-- _______________________________________________________________________ -->
6379<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6380 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6381</div>
6382
6383<div class="doc_text">
6384
6385<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6386<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6387 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6388
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6389<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6390 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6391 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6392 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6393</pre>
6394
6395<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6396<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6397 values with an even number of bytes (positive multiple of 16 bits). These
6398 are useful for performing operations on data that is not in the target's
6399 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6400
6401<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6402<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6403 and low byte of the input i16 swapped. Similarly,
6404 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6405 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6406 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6407 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6408 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6409 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6410
6411</div>
6412
6413<!-- _______________________________________________________________________ -->
6414<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6415 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6416</div>
6417
6418<div class="doc_text">
6419
6420<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6421<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]6422 width. Not all targets support all bit widths however.</p>
6423
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6424<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6425 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6426 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6427 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6428 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6429 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6430</pre>
6431
6432<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6433<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6434 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6435
6436<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6437<p>The only argument is the value to be counted. The argument may be of any
6438 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6439
6440<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6441<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]6442
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6443</div>
6444
6445<!-- _______________________________________________________________________ -->
6446<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6447 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6448</div>
6449
6450<div class="doc_text">
6451
6452<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6453<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6454 integer bit width. Not all targets support all bit widths however.</p>
6455
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6456<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6457 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6458 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6459 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6460 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6461 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6462</pre>
6463
6464<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6465<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6466 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6467
6468<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6469<p>The only argument is the value to be counted. The argument may be of any
6470 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6471
6472<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6473<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6474 zeros in a variable. If the src == 0 then the result is the size in bits of
6475 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6476
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6477</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6478
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6479<!-- _______________________________________________________________________ -->
6480<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6481 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6482</div>
6483
6484<div class="doc_text">
6485
6486<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6487<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6488 integer bit width. Not all targets support all bit widths however.</p>
6489
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6490<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6491 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6492 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6493 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6494 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6495 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6496</pre>
6497
6498<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6499<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6500 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6501
6502<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6503<p>The only argument is the value to be counted. The argument may be of any
6504 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6505
6506<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6507<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6508 zeros in a variable. If the src == 0 then the result is the size in bits of
6509 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6510
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6511</div>
6512
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6513<!-- ======================================================================= -->
6514<div class="doc_subsection">
6515 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6516</div>
6517
6518<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6519
6520<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6521
6522</div>
6523
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6524<!-- _______________________________________________________________________ -->
6525<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6526 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6527</div>
6528
6529<div class="doc_text">
6530
6531<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6532<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]6533 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6534
6535<pre>
6536 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6537 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6538 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6539</pre>
6540
6541<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6542<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6543 a signed addition of the two arguments, and indicate whether an overflow
6544 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6545
6546<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6547<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]6548 be of integer types of any bit width, but they must have the same bit
6549 width. The second element of the result structure must be of
6550 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6551 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6552
6553<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6554<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6555 a signed addition of the two variables. They return a structure &mdash; the
6556 first element of which is the signed summation, and the second element of
6557 which is a bit specifying if the signed summation resulted in an
6558 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6559
6560<h5>Examples:</h5>
6561<pre>
6562 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6563 %sum = extractvalue {i32, i1} %res, 0
6564 %obit = extractvalue {i32, i1} %res, 1
6565 br i1 %obit, label %overflow, label %normal
6566</pre>
6567
6568</div>
6569
6570<!-- _______________________________________________________________________ -->
6571<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6572 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6573</div>
6574
6575<div class="doc_text">
6576
6577<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6578<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]6579 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6580
6581<pre>
6582 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6583 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6584 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6585</pre>
6586
6587<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6588<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6589 an unsigned addition of the two arguments, and indicate whether a carry
6590 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6591
6592<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6593<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]6594 be of integer types of any bit width, but they must have the same bit
6595 width. The second element of the result structure must be of
6596 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6597 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6598
6599<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6600<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6601 an unsigned addition of the two arguments. They return a structure &mdash;
6602 the first element of which is the sum, and the second element of which is a
6603 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6604
6605<h5>Examples:</h5>
6606<pre>
6607 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6608 %sum = extractvalue {i32, i1} %res, 0
6609 %obit = extractvalue {i32, i1} %res, 1
6610 br i1 %obit, label %carry, label %normal
6611</pre>
6612
6613</div>
6614
6615<!-- _______________________________________________________________________ -->
6616<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6617 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6618</div>
6619
6620<div class="doc_text">
6621
6622<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6623<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]6624 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6625
6626<pre>
6627 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6628 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6629 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6630</pre>
6631
6632<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6633<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6634 a signed subtraction of the two arguments, and indicate whether an overflow
6635 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6636
6637<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6638<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]6639 be of integer types of any bit width, but they must have the same bit
6640 width. The second element of the result structure must be of
6641 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6642 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6643
6644<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6645<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6646 a signed subtraction of the two arguments. They return a structure &mdash;
6647 the first element of which is the subtraction, and the second element of
6648 which is a bit specifying if the signed subtraction resulted in an
6649 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6650
6651<h5>Examples:</h5>
6652<pre>
6653 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6654 %sum = extractvalue {i32, i1} %res, 0
6655 %obit = extractvalue {i32, i1} %res, 1
6656 br i1 %obit, label %overflow, label %normal
6657</pre>
6658
6659</div>
6660
6661<!-- _______________________________________________________________________ -->
6662<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6663 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6664</div>
6665
6666<div class="doc_text">
6667
6668<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6669<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]6670 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6671
6672<pre>
6673 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6674 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6675 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6676</pre>
6677
6678<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6679<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6680 an unsigned subtraction of the two arguments, and indicate whether an
6681 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6682
6683<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6684<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]6685 be of integer types of any bit width, but they must have the same bit
6686 width. The second element of the result structure must be of
6687 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6688 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6689
6690<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6691<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6692 an unsigned subtraction of the two arguments. They return a structure &mdash;
6693 the first element of which is the subtraction, and the second element of
6694 which is a bit specifying if the unsigned subtraction resulted in an
6695 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6696
6697<h5>Examples:</h5>
6698<pre>
6699 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6700 %sum = extractvalue {i32, i1} %res, 0
6701 %obit = extractvalue {i32, i1} %res, 1
6702 br i1 %obit, label %overflow, label %normal
6703</pre>
6704
6705</div>
6706
6707<!-- _______________________________________________________________________ -->
6708<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6709 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6710</div>
6711
6712<div class="doc_text">
6713
6714<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6715<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]6716 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6717
6718<pre>
6719 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6720 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6721 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6722</pre>
6723
6724<h5>Overview:</h5>
6725
6726<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6727 a signed multiplication of the two arguments, and indicate whether an
6728 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6729
6730<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6731<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]6732 be of integer types of any bit width, but they must have the same bit
6733 width. The second element of the result structure must be of
6734 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6735 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6736
6737<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6738<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6739 a signed multiplication of the two arguments. They return a structure &mdash;
6740 the first element of which is the multiplication, and the second element of
6741 which is a bit specifying if the signed multiplication resulted in an
6742 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6743
6744<h5>Examples:</h5>
6745<pre>
6746 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6747 %sum = extractvalue {i32, i1} %res, 0
6748 %obit = extractvalue {i32, i1} %res, 1
6749 br i1 %obit, label %overflow, label %normal
6750</pre>
6751
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6752</div>
6753
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6754<!-- _______________________________________________________________________ -->
6755<div class="doc_subsubsection">
6756 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6757</div>
6758
6759<div class="doc_text">
6760
6761<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6762<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]6763 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6764
6765<pre>
6766 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6767 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6768 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6769</pre>
6770
6771<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6772<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6773 a unsigned multiplication of the two arguments, and indicate whether an
6774 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6775
6776<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6777<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]6778 be of integer types of any bit width, but they must have the same bit
6779 width. The second element of the result structure must be of
6780 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6781 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6782
6783<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6784<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6785 an unsigned multiplication of the two arguments. They return a structure
6786 &mdash; the first element of which is the multiplication, and the second
6787 element of which is a bit specifying if the unsigned multiplication resulted
6788 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6789
6790<h5>Examples:</h5>
6791<pre>
6792 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6793 %sum = extractvalue {i32, i1} %res, 0
6794 %obit = extractvalue {i32, i1} %res, 1
6795 br i1 %obit, label %overflow, label %normal
6796</pre>
6797
6798</div>
6799
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6800<!-- ======================================================================= -->
6801<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6802 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6803</div>
6804
6805<div class="doc_text">
6806
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6807<p>Half precision floating point is a storage-only format. This means that it is
6808 a dense encoding (in memory) but does not support computation in the
6809 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6810
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6811<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6812 value as an i16, then convert it to float with <a
6813 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6814 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6815 double etc). To store the value back to memory, it is first converted to
6816 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6817 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6818 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6819</div>
6820
6821<!-- _______________________________________________________________________ -->
6822<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6823 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6824</div>
6825
6826<div class="doc_text">
6827
6828<h5>Syntax:</h5>
6829<pre>
6830 declare i16 @llvm.convert.to.fp16(f32 %a)
6831</pre>
6832
6833<h5>Overview:</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
6836 floating point format.</p>
6837
6838<h5>Arguments:</h5>
6839<p>The intrinsic function contains single argument - the value to be
6840 converted.</p>
6841
6842<h5>Semantics:</h5>
6843<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6844 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6845 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6846 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6847
6848<h5>Examples:</h5>
6849<pre>
6850 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6851 store i16 %res, i16* @x, align 2
6852</pre>
6853
6854</div>
6855
6856<!-- _______________________________________________________________________ -->
6857<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6858 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6859</div>
6860
6861<div class="doc_text">
6862
6863<h5>Syntax:</h5>
6864<pre>
6865 declare f32 @llvm.convert.from.fp16(i16 %a)
6866</pre>
6867
6868<h5>Overview:</h5>
6869<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6870 a conversion from half precision floating point format to single precision
6871 floating point format.</p>
6872
6873<h5>Arguments:</h5>
6874<p>The intrinsic function contains single argument - the value to be
6875 converted.</p>
6876
6877<h5>Semantics:</h5>
6878<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6879 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6880 precision floating point format. The input half-float value is represented by
6881 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6882
6883<h5>Examples:</h5>
6884<pre>
6885 %a = load i16* @x, align 2
6886 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6887</pre>
6888
6889</div>
6890
6891<!-- ======================================================================= -->
6892<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6893 <a name="int_debugger">Debugger Intrinsics</a>
6894</div>
6895
6896<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6897
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6898<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6899 prefix), are described in
6900 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6901 Level Debugging</a> document.</p>
6902
6903</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6904
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6905<!-- ======================================================================= -->
6906<div class="doc_subsection">
6907 <a name="int_eh">Exception Handling Intrinsics</a>
6908</div>
6909
6910<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6911
6912<p>The LLVM exception handling intrinsics (which all start with
6913 <tt>llvm.eh.</tt> prefix), are described in
6914 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6915 Handling</a> document.</p>
6916
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6917</div>
6918
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6919<!-- ======================================================================= -->
6920<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6921 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6922</div>
6923
6924<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6925
6926<p>This intrinsic makes it possible to excise one parameter, marked with
6927 the <tt>nest</tt> attribute, from a function. The result is a callable
6928 function pointer lacking the nest parameter - the caller does not need to
6929 provide a value for it. Instead, the value to use is stored in advance in a
6930 "trampoline", a block of memory usually allocated on the stack, which also
6931 contains code to splice the nest value into the argument list. This is used
6932 to implement the GCC nested function address extension.</p>
6933
6934<p>For example, if the function is
6935 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6936 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6937 follows:</p>
6938
6939<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6940<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6941 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6942 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6943 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6944 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6945</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6946</div>
6947
6948<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6949 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6950
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6951</div>
6952
6953<!-- _______________________________________________________________________ -->
6954<div class="doc_subsubsection">
6955 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6956</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6957
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6958<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6959
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6960<h5>Syntax:</h5>
6961<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6962 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]6963</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6964
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6965<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6966<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6967 function pointer suitable for executing it.</p>
6968
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6969<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6970<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6971 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6972 sufficiently aligned block of memory; this memory is written to by the
6973 intrinsic. Note that the size and the alignment are target-specific - LLVM
6974 currently provides no portable way of determining them, so a front-end that
6975 generates this intrinsic needs to have some target-specific knowledge.
6976 The <tt>func</tt> argument must hold a function bitcast to
6977 an <tt>i8*</tt>.</p>
6978
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6979<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6980<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6981 dependent code, turning it into a function. A pointer to this function is
6982 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6983 function pointer type</a> before being called. The new function's signature
6984 is the same as that of <tt>func</tt> with any arguments marked with
6985 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6986 is allowed, and it must be of pointer type. Calling the new function is
6987 equivalent to calling <tt>func</tt> with the same argument list, but
6988 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6989 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6990 by <tt>tramp</tt> is modified, then the effect of any later call to the
6991 returned function pointer is undefined.</p>
6992
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6993</div>
6994
6995<!-- ======================================================================= -->
6996<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6997 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6998</div>
6999
7000<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7001
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7002<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7003 hardware constructs for atomic operations and memory synchronization. This
7004 provides an interface to the hardware, not an interface to the programmer. It
7005 is aimed at a low enough level to allow any programming models or APIs
7006 (Application Programming Interfaces) which need atomic behaviors to map
7007 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7008 hardware provides a "universal IR" for source languages, it also provides a
7009 starting point for developing a "universal" atomic operation and
7010 synchronization IR.</p>
7011
7012<p>These do <em>not</em> form an API such as high-level threading libraries,
7013 software transaction memory systems, atomic primitives, and intrinsic
7014 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7015 application libraries. The hardware interface provided by LLVM should allow
7016 a clean implementation of all of these APIs and parallel programming models.
7017 No one model or paradigm should be selected above others unless the hardware
7018 itself ubiquitously does so.</p>
7019
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7020</div>
7021
7022<!-- _______________________________________________________________________ -->
7023<div class="doc_subsubsection">
7024 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7025</div>
7026<div class="doc_text">
7027<h5>Syntax:</h5>
7028<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7029 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]7030</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7031
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7032<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7033<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7034 specific pairs of memory access types.</p>
7035
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7036<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7037<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7038 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7039 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7040 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7041
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7042<ul>
7043 <li><tt>ll</tt>: load-load barrier</li>
7044 <li><tt>ls</tt>: load-store barrier</li>
7045 <li><tt>sl</tt>: store-load barrier</li>
7046 <li><tt>ss</tt>: store-store barrier</li>
7047 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7048</ul>
7049
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7050<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7051<p>This intrinsic causes the system to enforce some ordering constraints upon
7052 the loads and stores of the program. This barrier does not
7053 indicate <em>when</em> any events will occur, it only enforces
7054 an <em>order</em> in which they occur. For any of the specified pairs of load
7055 and store operations (f.ex. load-load, or store-load), all of the first
7056 operations preceding the barrier will complete before any of the second
7057 operations succeeding the barrier begin. Specifically the semantics for each
7058 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7059
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7060<ul>
7061 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7062 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7063 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7064 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7065 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7066 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7067 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7068 load after the barrier begins.</li>
7069</ul>
7070
7071<p>These semantics are applied with a logical "and" behavior when more than one
7072 is enabled in a single memory barrier intrinsic.</p>
7073
7074<p>Backends may implement stronger barriers than those requested when they do
7075 not support as fine grained a barrier as requested. Some architectures do
7076 not need all types of barriers and on such architectures, these become
7077 noops.</p>
7078
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7079<h5>Example:</h5>
7080<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7081%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7082%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7083 store i32 4, %ptr
7084
7085%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
7086 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
7087 <i>; guarantee the above finishes</i>
7088 store i32 8, %ptr <i>; before this begins</i>
7089</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7090
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7091</div>
7092
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7093<!-- _______________________________________________________________________ -->
7094<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7095 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7096</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7097
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7098<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7099
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7100<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7101<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7102 any integer bit width and for different address spaces. Not all targets
7103 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7104
7105<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7106 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
7107 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
7108 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
7109 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]7110</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7111
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7112<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7113<p>This loads a value in memory and compares it to a given value. If they are
7114 equal, it stores a new value into the memory.</p>
7115
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7116<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7117<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7118 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7119 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7120 this integer type. While any bit width integer may be used, targets may only
7121 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7122
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7123<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7124<p>This entire intrinsic must be executed atomically. It first loads the value
7125 in memory pointed to by <tt>ptr</tt> and compares it with the
7126 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7127 memory. The loaded value is yielded in all cases. This provides the
7128 equivalent of an atomic compare-and-swap operation within the SSA
7129 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7130
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7131<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7132<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7133%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7134%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7135 store i32 4, %ptr
7136
7137%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7138%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7139 <i>; yields {i32}:result1 = 4</i>
7140%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7141%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7142
7143%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7144%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7145 <i>; yields {i32}:result2 = 8</i>
7146%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7147
7148%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7149</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7150
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7151</div>
7152
7153<!-- _______________________________________________________________________ -->
7154<div class="doc_subsubsection">
7155 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7156</div>
7157<div class="doc_text">
7158<h5>Syntax:</h5>
7159
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7160<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7161 integer bit width. Not all targets support all bit widths however.</p>
7162
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7163<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7164 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
7165 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
7166 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
7167 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]7168</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7169
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7170<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7171<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7172 the value from memory. It then stores the value in <tt>val</tt> in the memory
7173 at <tt>ptr</tt>.</p>
7174
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7175<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7176<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7177 the <tt>val</tt> argument and the result must be integers of the same bit
7178 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7179 integer type. The targets may only lower integer representations they
7180 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7181
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7182<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7183<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7184 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7185 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7186
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7187<h5>Examples:</h5>
7188<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7189%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7190%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7191 store i32 4, %ptr
7192
7193%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7194%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7195 <i>; yields {i32}:result1 = 4</i>
7196%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7197%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7198
7199%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7200%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7201 <i>; yields {i32}:result2 = 8</i>
7202
7203%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7204%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7205</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7206
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7207</div>
7208
7209<!-- _______________________________________________________________________ -->
7210<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7211 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7212
7213</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7214
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7215<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7216
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7217<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7218<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7219 any integer bit width. Not all targets support all bit widths however.</p>
7220
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7221<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7222 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7223 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7224 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7225 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]7226</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7227
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7228<h5>Overview:</h5>
7229<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7230 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7231
7232<h5>Arguments:</h5>
7233<p>The intrinsic takes two arguments, the first a pointer to an integer value
7234 and the second an integer value. The result is also an integer value. These
7235 integer types can have any bit width, but they must all have the same bit
7236 width. The targets may only lower integer representations they support.</p>
7237
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7238<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7239<p>This intrinsic does a series of operations atomically. It first loads the
7240 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7241 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]7242
7243<h5>Examples:</h5>
7244<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7245%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7246%ptr = bitcast i8* %mallocP to i32*
7247 store i32 4, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7248%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7249 <i>; yields {i32}:result1 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7250%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7251 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7252%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7253 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7254%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7255</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7256
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7257</div>
7258
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7259<!-- _______________________________________________________________________ -->
7260<div class="doc_subsubsection">
7261 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7262
7263</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7264
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7265<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7266
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7267<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7268<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7269 any integer bit width and for different address spaces. Not all targets
7270 support all bit widths however.</p>
7271
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7272<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7273 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7274 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7275 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7276 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]7277</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7278
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7279<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7280<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7281 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7282
7283<h5>Arguments:</h5>
7284<p>The intrinsic takes two arguments, the first a pointer to an integer value
7285 and the second an integer value. The result is also an integer value. These
7286 integer types can have any bit width, but they must all have the same bit
7287 width. The targets may only lower integer representations they support.</p>
7288
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7289<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7290<p>This intrinsic does a series of operations atomically. It first loads the
7291 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7292 result to <tt>ptr</tt>. It yields the original value stored
7293 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7294
7295<h5>Examples:</h5>
7296<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7297%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7298%ptr = bitcast i8* %mallocP to i32*
7299 store i32 8, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7300%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7301 <i>; yields {i32}:result1 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7302%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7303 <i>; yields {i32}:result2 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7304%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7305 <i>; yields {i32}:result3 = 2</i>
7306%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7307</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7308
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7309</div>
7310
7311<!-- _______________________________________________________________________ -->
7312<div class="doc_subsubsection">
7313 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7314 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7315 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7316 <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]7317</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7318
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7319<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7320
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7321<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7322<p>These are overloaded intrinsics. You can
7323 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7324 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7325 bit width and for different address spaces. Not all targets support all bit
7326 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7327
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7328<pre>
7329 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7330 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7331 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7332 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]7333</pre>
7334
7335<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7336 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7337 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7338 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7339 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]7340</pre>
7341
7342<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7343 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7344 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7345 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7346 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]7347</pre>
7348
7349<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7350 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7351 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7352 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7353 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]7354</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7355
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7356<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7357<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7358 the value stored in memory at <tt>ptr</tt>. It yields the original value
7359 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7360
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7361<h5>Arguments:</h5>
7362<p>These intrinsics take two arguments, the first a pointer to an integer value
7363 and the second an integer value. The result is also an integer value. These
7364 integer types can have any bit width, but they must all have the same bit
7365 width. The targets may only lower integer representations they support.</p>
7366
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7367<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7368<p>These intrinsics does a series of operations atomically. They first load the
7369 value stored at <tt>ptr</tt>. They then do the bitwise
7370 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7371 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7372
7373<h5>Examples:</h5>
7374<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7375%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7376%ptr = bitcast i8* %mallocP to i32*
7377 store i32 0x0F0F, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7378%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7379 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7380%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7381 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7382%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7383 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7384%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7385 <i>; yields {i32}:result3 = FF</i>
7386%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7387</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7388
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7389</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7390
7391<!-- _______________________________________________________________________ -->
7392<div class="doc_subsubsection">
7393 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7394 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7395 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7396 <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]7397</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7398
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7399<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7400
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7401<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7402<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7403 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7404 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7405 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7406
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7407<pre>
7408 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7409 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7410 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7411 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]7412</pre>
7413
7414<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7415 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7416 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7417 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7418 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]7419</pre>
7420
7421<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7422 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7423 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7424 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7425 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]7426</pre>
7427
7428<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7429 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7430 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7431 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7432 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]7433</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7434
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7435<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7436<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7437 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7438 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7439
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7440<h5>Arguments:</h5>
7441<p>These intrinsics take two arguments, the first a pointer to an integer value
7442 and the second an integer value. The result is also an integer value. These
7443 integer types can have any bit width, but they must all have the same bit
7444 width. The targets may only lower integer representations they support.</p>
7445
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7446<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7447<p>These intrinsics does a series of operations atomically. They first load the
7448 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7449 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7450 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7451
7452<h5>Examples:</h5>
7453<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7454%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7455%ptr = bitcast i8* %mallocP to i32*
7456 store i32 7, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7457%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7458 <i>; yields {i32}:result0 = 7</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7459%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7460 <i>; yields {i32}:result1 = -2</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7461%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7462 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7463%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7464 <i>; yields {i32}:result3 = 8</i>
7465%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7466</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7467
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7468</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7469
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7470
7471<!-- ======================================================================= -->
7472<div class="doc_subsection">
7473 <a name="int_memorymarkers">Memory Use Markers</a>
7474</div>
7475
7476<div class="doc_text">
7477
7478<p>This class of intrinsics exists to information about the lifetime of memory
7479 objects and ranges where variables are immutable.</p>
7480
7481</div>
7482
7483<!-- _______________________________________________________________________ -->
7484<div class="doc_subsubsection">
7485 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7486</div>
7487
7488<div class="doc_text">
7489
7490<h5>Syntax:</h5>
7491<pre>
7492 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7493</pre>
7494
7495<h5>Overview:</h5>
7496<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7497 object's lifetime.</p>
7498
7499<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7500<p>The first argument is a constant integer representing the size of the
7501 object, or -1 if it is variable sized. The second argument is a pointer to
7502 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7503
7504<h5>Semantics:</h5>
7505<p>This intrinsic indicates that before this point in the code, the value of the
7506 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]7507 never be used and has an undefined value. A load from the pointer that
7508 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7509 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7510
7511</div>
7512
7513<!-- _______________________________________________________________________ -->
7514<div class="doc_subsubsection">
7515 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7516</div>
7517
7518<div class="doc_text">
7519
7520<h5>Syntax:</h5>
7521<pre>
7522 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7523</pre>
7524
7525<h5>Overview:</h5>
7526<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7527 object's lifetime.</p>
7528
7529<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7530<p>The first argument is a constant integer representing the size of the
7531 object, or -1 if it is variable sized. The second argument is a pointer to
7532 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7533
7534<h5>Semantics:</h5>
7535<p>This intrinsic indicates that after this point in the code, the value of the
7536 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7537 never be used and has an undefined value. Any stores into the memory object
7538 following this intrinsic may be removed as dead.
7539
7540</div>
7541
7542<!-- _______________________________________________________________________ -->
7543<div class="doc_subsubsection">
7544 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7545</div>
7546
7547<div class="doc_text">
7548
7549<h5>Syntax:</h5>
7550<pre>
7551 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7552</pre>
7553
7554<h5>Overview:</h5>
7555<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7556 a memory object will not change.</p>
7557
7558<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7559<p>The first argument is a constant integer representing the size of the
7560 object, or -1 if it is variable sized. The second argument is a pointer to
7561 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7562
7563<h5>Semantics:</h5>
7564<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7565 the return value, the referenced memory location is constant and
7566 unchanging.</p>
7567
7568</div>
7569
7570<!-- _______________________________________________________________________ -->
7571<div class="doc_subsubsection">
7572 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7573</div>
7574
7575<div class="doc_text">
7576
7577<h5>Syntax:</h5>
7578<pre>
7579 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7580</pre>
7581
7582<h5>Overview:</h5>
7583<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7584 a memory object are mutable.</p>
7585
7586<h5>Arguments:</h5>
7587<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7588 The second argument is a constant integer representing the size of the
7589 object, or -1 if it is variable sized and the third argument is a pointer
7590 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7591
7592<h5>Semantics:</h5>
7593<p>This intrinsic indicates that the memory is mutable again.</p>
7594
7595</div>
7596
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7597<!-- ======================================================================= -->
7598<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7599 <a name="int_general">General Intrinsics</a>
7600</div>
7601
7602<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7603
7604<p>This class of intrinsics is designed to be generic and has no specific
7605 purpose.</p>
7606
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7607</div>
7608
7609<!-- _______________________________________________________________________ -->
7610<div class="doc_subsubsection">
7611 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7612</div>
7613
7614<div class="doc_text">
7615
7616<h5>Syntax:</h5>
7617<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]7618 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]7619</pre>
7620
7621<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7622<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7623
7624<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7625<p>The first argument is a pointer to a value, the second is a pointer to a
7626 global string, the third is a pointer to a global string which is the source
7627 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7628
7629<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7630<p>This intrinsic allows annotation of local variables with arbitrary strings.
7631 This can be useful for special purpose optimizations that want to look for
7632 these annotations. These have no other defined use, they are ignored by code
7633 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7634
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7635</div>
7636
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7637<!-- _______________________________________________________________________ -->
7638<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7639 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7640</div>
7641
7642<div class="doc_text">
7643
7644<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7645<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7646 any integer bit width.</p>
7647
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7648<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]7649 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7650 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7651 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7652 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7653 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]7654</pre>
7655
7656<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7657<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7658
7659<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7660<p>The first argument is an integer value (result of some expression), the
7661 second is a pointer to a global string, the third is a pointer to a global
7662 string which is the source file name, and the last argument is the line
7663 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7664
7665<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7666<p>This intrinsic allows annotations to be put on arbitrary expressions with
7667 arbitrary strings. This can be useful for special purpose optimizations that
7668 want to look for these annotations. These have no other defined use, they
7669 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7670
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7671</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7672
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7673<!-- _______________________________________________________________________ -->
7674<div class="doc_subsubsection">
7675 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7676</div>
7677
7678<div class="doc_text">
7679
7680<h5>Syntax:</h5>
7681<pre>
7682 declare void @llvm.trap()
7683</pre>
7684
7685<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7686<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7687
7688<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7689<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7690
7691<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7692<p>This intrinsics is lowered to the target dependent trap instruction. If the
7693 target does not have a trap instruction, this intrinsic will be lowered to
7694 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7695
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7696</div>
7697
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7698<!-- _______________________________________________________________________ -->
7699<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7700 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7701</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7702
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7703<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7704
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7705<h5>Syntax:</h5>
7706<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7707 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7708</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7709
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7710<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7711<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7712 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7713 ensure that it is placed on the stack before local variables.</p>
7714
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7715<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7716<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7717 arguments. The first argument is the value loaded from the stack
7718 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7719 that has enough space to hold the value of the guard.</p>
7720
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7721<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7722<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7723 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7724 stack. This is to ensure that if a local variable on the stack is
7725 overwritten, it will destroy the value of the guard. When the function exits,
7726 the guard on the stack is checked against the original guard. If they're
7727 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7728 function.</p>
7729
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7730</div>
7731
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7732<!-- _______________________________________________________________________ -->
7733<div class="doc_subsubsection">
7734 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7735</div>
7736
7737<div class="doc_text">
7738
7739<h5>Syntax:</h5>
7740<pre>
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7741 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7742 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7743</pre>
7744
7745<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7746<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7747 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7748 operation like memcpy will either overflow a buffer that corresponds to
7749 an object, or b) to determine that a runtime check for overflow isn't
7750 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7751 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7752
7753<h5>Arguments:</h5>
7754<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7755 argument is a pointer to or into the <tt>object</tt>. The second argument
7756 is a boolean 0 or 1. This argument determines whether you want the
7757 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7758 1, variables are not allowed.</p>
7759
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7760<h5>Semantics:</h5>
7761<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7762 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7763 (depending on the <tt>type</tt> argument if the size cannot be determined
7764 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7765
7766</div>
7767
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7768<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7769<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7770<address>
7771 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7772 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7773 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7774 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]7775
7776 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7777 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7778 Last modified: $Date$
7779</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7780
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7781</body>
7782</html>